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  • 1.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Nonparametric structural damage detection algorithm for ambient vibration response: utilizing artificial neural networks and self-organizing maps2016In: Journal of Architectural Engineering, ISSN 1076-0431, E-ISSN 1943-5568, Vol. 22, no 2Article in journal (Refereed)
    Abstract [en]

    This study presentes a new nonparametric structural damage detection algorithm that integrates self-organizing maps with a pattern-recognition neural network to quantify and locate structural damage. In this algorithm, self-organizing maps are used to extract a number of damage indices from the ambient vibration response of the monitored structure. The presented study is unique because it demonstrates the development of a nonparametric vibration-based damage detection algorithm that utilizes self-organizing maps to extract meaningful damage indices from ambient vibration signals in the time domain. The ability of the algorithm to identify damage was demonstrated analytically using a finite-element model of a hot-rolled steel grid structure. The algorithm successfully located the structural damage under several damage cases, including damage resulting from local stiffness loss in members and damage resulting from changes in boundary conditions. A sensitivity study was also conducted to evaluate the effects of noise on the computed damage indices. The algorithm was proved to be successful even when the signals are noise-contaminated.

  • 2.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Do, Ngoan Tien
    University of Alberta, Canada.
    Gul, Mustafa
    University of Alberta, Canada.
    Celik, Ozan
    University of Central Florida, USA.
    Catbas, Necati
    University of Central Florida, USA.
    Quantification of Structural Damage with Self-Organizing Maps2016In: Structural Health Monitoring, Damage Detection & Mechatronics: Proceedings of the 34th IMAC, A Conference and Exposition on Structural Dynamics 2016, Springer, 2016, Vol. 7, p. 47-57Conference paper (Other academic)
    Abstract [en]

    One of the main tasks in structural health monitoring process is to create reliable algorithms that are capable of translating the measured response into meaningful information reflecting the actual condition of the monitored structure. The authors have recently introduced a novel unsupervised vibration-based damage detection algorithm that utilizes self-organizing maps to quantify structural damage and assess the overall condition of structures. Previously, this algorithm had been tested using the experimental data of Phase II Experimental Benchmark Problem of Structural Health Monitoring, introduced by the IASC (International Association for Structural Control) and ASCE (American Society of Civil Engineers). In this paper, the ability of this algorithm to quantify structural damage is tested analytically using an experimentally validated finite element model of a laboratory structure constructed at Qatar University.

  • 3.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Active vibration control of flexible cantilever plates using piezoelectric materials and artificial neural networks2016In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 363, p. 33-53Article in journal (Refereed)
    Abstract [en]

    The study presented in this paper introduces a new intelligent methodology to mitigate the vibration response of flexible cantilever plates. The use of the piezoelectric sensor/actuator pairs for active control of plates is discussed. An intelligent neural network based controller is designed to control the optimal voltage applied on the piezoelectric patches. The control technique utilizes a neurocontroller along with a Kalman Filter to compute the appropriate actuator command. The neurocontroller is trained based on an algorithm that incorporates a set of emulator neural networks which are also trained to predict the future response of the cantilever plate. Then, the neurocontroller is evaluated by comparing the uncontrolled and controlled responses under several types of dynamic excitations. It is observed that the neurocontroller reduced the vibration response of the flexible cantilever plate significantly; the results demonstrated the success and robustness of the neurocontroller independent of the type and distribution of the excitation force.

  • 4.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Genetic algorithm use for internally resonating lattice optimization: case of a beam-like metastructure2016In: Dynamics of Civil Structures: Proceedings of the 34th IMAC, A Conference and Exposition on Structural Dynamics 2016 / [ed] Shamim Pakzad, Caicedo Juan, Springer, 2016, p. 289-295Conference paper (Other academic)
    Abstract [en]

    Metamaterial inspired structures, or metastructures, are structural members that incorporate periodic or non-periodic inserts. Recently, a new class of metastructures has been introduced which feature chiral lattice inserts. It was found that this type of inserts has frequency bandgaps which can be tuned by altering the geometry of the chiral lattice. Previous studies have shown that inserting non-periodic chiral lattices inside a beam-like structure results in efficient vibration attenuation at low frequencies. In the study presented in this paper, a genetic algorithm based optimization technique is developed to automatically generate chiral lattices which are tuned to suppress vibration in a flexible beam-like structure. Several parameters are incorporated in the optimization process such as the radius of circular nodes and characteristic angle as well as the spacing and distribution of circular inserts. The efficiency of the …

  • 5.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Optimization of chiral lattice based metastructures for broadband vibration suppression using genetic algorithms2016In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 369, p. 50-62Article in journal (Refereed)
    Abstract [en]

    One of the major challenges in civil, mechanical, and aerospace engineering is to develop vibration suppression systems with high efficiency and low cost. Recent studies have shown that high damping performance at broadband frequencies can be achieved by incorporating periodic inserts with tunable dynamic properties as internal resonators in structural systems. Structures featuring these kinds of inserts are referred to as metamaterials inspired structures or metastructures. Chiral lattice inserts exhibit unique characteristics such as frequency bandgaps which can be tuned by varying the parameters that define the lattice topology. Recent analytical and experimental investigations have shown that broadband vibration attenuation can be achieved by including chiral lattices as internal resonators in beam-like structures. However, these studies have suggested that the performance of chiral lattice inserts can be maximized by utilizing an efficient optimization technique to obtain the optimal topology of the inserted lattice. In this study, an automated optimization procedure based on a genetic algorithm is applied to obtain the optimal set of parameters that will result in chiral lattice inserts tuned properly to reduce the global vibration levels of a finite-sized beam. Genetic algorithms are considered in this study due to their capability of dealing with complex and insufficiently understood optimization problems. In the optimization process, the basic parameters that govern the geometry of periodic chiral lattices including the number of circular nodes, the thickness of the ligaments, and the characteristic angle are considered. Additionally, a new set of parameters is introduced to enable the optimization process to explore non-periodic chiral designs. Numerical simulations are carried out to demonstrate the efficiency of the optimization process.

  • 6.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Boashash, Boualem
    Qatar University, Qatar; The University of Queensland, Herston, Australia.
    Sodano, Henry
    University of Michigan, USA.
    Inman, Daniel
    University of Michigan, USA.
    1-D CNNs for structural damage detection: verification on a structural health monitoring benchmark data2018In: Neurocomputing, ISSN 0925-2312, E-ISSN 1872-8286, Vol. 275, p. 1308-1317Article in journal (Refereed)
    Abstract [en]

    Structural damage detection has been an interdisciplinary area of interest for various engineering fields. While the available damage detection methods have been in the process of adapting machine learning concepts, most machine learning based methods extract “hand-crafted” features which are fixed and manually selected in advance. Their performance varies significantly among various patterns of data depending on the particular structure under analysis. Convolutional neural networks (CNNs), on the other hand, can fuse and simultaneously optimize two major sets of an assessment task (feature extraction and classification) into a single learning block during the training phase. This ability not only provides an improved classification performance but also yields a superior computational efficiency. 1D CNNs have recently achieved state-of-the-art performance in vibration-based structural damage detection; however, it has been reported that the training of the CNNs requires significant amount of measurements especially in large structures. In order to overcome this limitation, this paper presents an enhanced CNN-based approach that requires only two measurement sets regardless of the size of the structure. This approach is verified using the experimental data of the Phase II benchmark problem of structural health monitoring which had been introduced by IASC-ASCE Structural Health Monitoring Task Group. As a result, it is shown that the enhanced CNN-based approach successfully estimated the actual amount of damage for the nine damage scenarios of the benchmark study.

  • 7.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Gabbouj, Moncef
    Tampere University of Technology, Finland.
    Inman, Daniel
    University of Michigan, USA.
    Real-time vibration-based structural damage detection using one-dimensional convolutional neural networks2017In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 388, p. 154-170Article in journal (Refereed)
    Abstract [en]

    Structural health monitoring (SHM) and vibration-based structural damage detection have been a continuous interest for civil, mechanical and aerospace engineers over the decades. Early and meticulous damage detection has always been one of the principal objectives of SHM applications. The performance of a classical damage detection system predominantly depends on the choice of the features and the classifier. While the fixed and hand-crafted features may either be a sub-optimal choice for a particular structure or fail to achieve the same level of performance on another structure, they usually require a large computation power which may hinder their usage for real-time structural damage detection. This paper presents a novel, fast and accurate structural damage detection system using 1D Convolutional Neural Networks (CNNs) that has an inherent adaptive design to fuse both feature extraction and classification blocks into a single and compact learning body. The proposed method performs vibration-based damage detection and localization of the damage in real-time. The advantage of this approach is its ability to extract optimal damage-sensitive features automatically from the raw acceleration signals. Large-scale experiments conducted on a grandstand simulator revealed an outstanding performance and verified the computational efficiency of the proposed real-time damage detection method.

  • 8.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Optimization of linear zigzag insert metastructures for low-frequency vibration attenuation using genetic algorithms2017In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 84, no Part A, p. 625-641Article in journal (Refereed)
    Abstract [en]

    Vibration suppression remains a crucial issue in the design of structures and machines. Recent studies have shown that with the use of metamaterial inspired structures (or metastructures), considerable vibration attenuation can be achieved. Optimization of the internal geometry of metastructures maximizes the suppression performance. Zigzag inserts have been reported to be efficient for vibration attenuation. It has also been reported that the geometric parameters of the inserts affect the vibration suppression performance in a complex manner. In an attempt to find out the most efficient parameters, an optimization study has been conducted on the linear zigzag inserts and is presented here. The research reported in this paper aims at developing an automated method for determining the geometry of zigzag inserts through optimization. This genetic algorithm based optimization process searches for optimal zigzag designs which are properly tuned to suppress vibrations when inserted in a specific host structure (cantilever beam). The inserts adopted in this study consist of a cantilever zigzag structure with a mass attached to its unsupported tip. Numerical simulations are carried out to demonstrate the efficiency of the proposed zigzag optimization approach.

  • 9.
    Abdula, Sham
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oksman, Dan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Attefallshus som komplementbostadshus: Drömhus eller mardröm?2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den 2 juli 2014 blev det enligt lag tillåtet för en- och tvåbostadshusägare att uppföra en bygglovsbefriad komplementbyggnad på max 25 kvadratmeter på den egna fastigheten. Rapporten undersöker vilket genomslag lagändringen har haft i Stor-Stockholm, Stor-Göteborg och Stor-Malmö. Undersökningen visar att lagändringen ännu inte har haft något stort genomslag. I rapporten undersöks även en utvald del av marknadsaktörers utbud av attefallshus avsett som komplementbostadshus. 

    Ett attefallshus utformas med miljövänligt hållbara material och inspireras av Vitruvius tre principer för god arkitektur. Huset konstrueras med avsikt att uppfylla kraven som ställs i PBL, PBF, BBR och EKS. Målet med de framtagna bygghandlingarna är att få startbesked från byggnadsnämnden i Växjö. 

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  • 10.
    Andersson, Bernt-Ove
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Malmstedt, Anthon
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Innovativa boendeformer för unga vuxna: En möjlig väg in på den svenska bostadsmarknaden2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This work concerns the examination of the interest and awareness of three innovative forms of housing that target young adults between the ages of 18 and 35 in the Swedish housing market. It also describes the existing stock of housing and highlights the most serious obstacles for the target group to obtain an accommodation. The work takes it’s starting point in the current housing shortage in Sweden where many groups for various reasons are hindered from the housing market for various reasons. The market is in need for public actors and various housing developers to find new ways to remedy the problem of obtaining an accommodation for these vulnerable groups. The study is based on previous research, surveys with young adults and interviews with intermediaries from different parts of the industry as a methodology. The results show an interest for, but low knowledge about the three types of housing: rent purchases, youth sets and cooperative rental apartments adapted for young adults. These are all adapted to reduce the problem for some persons within the target group to enter the housing market.

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  • 11.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Self-organizing maps for structural damage detection: a novel unsupervised vibration-based algorithm2016In: Journal of performance of constructed facilities, ISSN 0887-3828, E-ISSN 1943-5509, Vol. 30, no 3Article in journal (Refereed)
    Abstract [en]

    The study presented in this paper is arguably the first study to use a self-organizing map (SOM) for global structural damage detection. A novel unsupervised vibration-based damage detection algorithm is introduced using SOMs in order to quantify structural damage. In this algorithm, SOMs are used to extract a number of damage indices from the random acceleration response of the monitored structure in the time domain. The summation of the indices is used as an indicator which reflects the overall condition of the structure. The ability of the algorithm to quantify the overall structural damage is demonstrated using experimental data of Phase II experimental benchmark problem of structural health monitoring.

  • 12.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Boashash, Boualem
    University of Queensland, Australia.
    Sodano, Henry
    University of Michigan, USA.
    Inman, Daniel
    University of Michigan, USA.
    Efficiency Validation of One Dimensional Convolutional Neural Networks for Structural Damage Detection Using A SHM Benchmark Data2018In: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling, International Institute of Acoustics and Vibration (IIAV) , 2018, p. 4600-4607Conference paper (Other academic)
    Abstract [en]

    In this paper, a novel one dimensional convolution neural network (1D-CNN) based structural damage assessment technique is validated with a benchmark study published by IASC-ASCE Structural Health Monitoring Task Group in 2003. In contrast with predominant machine learning based structural damage detection techniques of the literature, the technique shown in this paper runs without manual feature extraction or preprocessing stages. It runs directly on the raw vibration data. In CNNs, the stages of feature extraction and feature classification are merged into one stage; therefore, the proposed technique is efficient, feasible and economical. Utilizing the optimal features learned by 1D CNNs, the proposed CNN-based technique considerably improves the classification efficiency and accuracy. The performance improvement of the proposed technique is assessed by calculating the “Probability of Damage” values for damage estimations. The unseen structural damage cases between the two extreme end structural cases (zero damage and total damage) were successfully identified. Consequently, it is validated that the improved CNN-based technique is efficient since it predicted the level of damage consistently with the structural damage cases defined in the existing benchmark.

  • 13.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Hussein, Mohammed
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Wireless and real-time structural damage detection: a novel decentralized method for wireless sensor networks2018In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 424, p. 158-172Article in journal (Refereed)
    Abstract [en]

    Being an alternative to conventional wired sensors, wireless sensor networks (WSNs) are extensively used in Structural Health Monitoring (SHM) applications. Most of the Structural Damage Detection (SDD) approaches available in the SHM literature are centralized as they require transferring data from all sensors within the network to a single processing unit to evaluate the structural condition. These methods are found predominantly feasible for wired SHM systems; however, transmission and synchronization of huge data sets in WSNs has been found to be arduous. As such, the application of centralized methods with WSNs has been a challenge for engineers. In this paper, the authors are presenting a novel application of 1D Convolutional Neural Networks (1D CNNs) on WSNs for SDD purposes. The SDD is successfully performed completely wireless and real-time under ambient conditions. As a result of this, a decentralized damage detection method suitable for wireless SHM systems is proposed. The proposed method is based on 1D CNNs and it involves training an individual 1D CNN for each wireless sensor in the network in a format where each CNN is assigned to process the locally-available data only, eliminating the need for data transmission and synchronization. The proposed damage detection method operates directly on the raw ambient vibration condition signals without any filtering or preprocessing. Moreover, the proposed approach requires minimal computational time and power since 1D CNNs merge both feature extraction and classification tasks into a single learning block. This ability is prevailingly cost-effective and evidently practical in WSNs considering the hardware systems have been occasionally reported to suffer from limited power supply in these networks. To display the capability and verify the success of the proposed method, large-scale experiments conducted on a laboratory structure equipped with a state-of-the-art WSN are reported.

  • 14.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Control of Plate Vibrations with Artificial Neural Networks and Piezoelectricity2020In: Sensors and Instrumentation, Aircraft/Aerospace, Energy Harvesting & Dynamic Environments Testing: Proceedings of the 37th IMAC, A Conference and Exposition on Structural Dynamics 2019 / [ed] Chad WalberPatrick WalterSteve Seidlitz, Springer, 2020, p. 293-301Conference paper (Other academic)
    Abstract [en]

    This paper presents a method for active vibration control of smart thin cantilever plates. For model formulation needed for controller design and simulations, finite difference technique is used on the cantilever plate response calculations. Piezoelectric patches are used on the plate, for which a neural network based control algorithm is formed and a neurocontroller is produced to calculate the required voltage to be applied on the actuator patch. The neurocontroller is trained and run with a Kalman Filter for controlling the structural response. The neurocontroller performance is assessed by comparing the controlled and uncontrolled structural responses when the plate is subjected to various excitations. It is shown that the acceleration response of the cantilever plate is suppressed considerably validating the efficacy of the neurocontroller and the success of the proposed methodology.

  • 15.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Convolutional Neural Networks for Real-Time and Wireless Damage Detection2020In: Dynamics of Civil Structures: Proceedings of the 37th IMAC, A Conference and Exposition on Structural Dynamics 2019 / [ed] Shamim Pakzad, Springer, 2020, p. 129-136Conference paper (Other academic)
    Abstract [en]

    Structural damage detection methods available for structural health monitoring applications are based on data preprocessing, feature extraction, and feature classification. The feature classification task requires considerable computational power which makes the utilization of centralized techniques relatively infeasible for wireless sensor networks. In this paper, the authors present a novel Wireless Sensor Network (WSN) based on One Dimensional Convolutional Neural Networks (1D CNNs) for real-time and wireless structural health monitoring (SHM). In this method, each CNN is assigned to its local sensor data only and a corresponding 1D CNN is trained for each sensor unit without any synchronization or data transmission. This results in a decentralized system for structural damage detection under ambient environment. The performance of this method is tested and validated on a steel grid laboratory structure.

  • 16.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Structural Damage Detection in Real Time: Implementation of 1D Convolutional Neural Networks for SHM Applications2017In: Structural Health Monitoring & Damage Detection, Volume 7: Proceedings of the 35th IMAC, A Conference and Exposition on Structural Dynamics 2017 / [ed] Christopher Niezrecki, Springer, 2017, Vol. 7, p. 49-54Conference paper (Other academic)
    Abstract [en]

    Most of the classical structural damage detection systems involve two processes, feature extraction and feature classification. Usually, the feature extraction process requires large computational effort which prevent the application of the classical methods in real-time structural health monitoring applications. Furthermore, in many cases, the hand-crafted features extracted by the classical methods fail to accurately characterize the acquired signal, resulting in poor classification performance. In an attempt to overcome these issues, this paper presents a novel, fast and accurate structural damage detection and localization system utilizing one dimensional convolutional neural networks (CNNs) arguably for the first time in SHM applications. The proposed method is capable of extracting optimal damage-sensitive features automatically from the raw acceleration signals, allowing it to be used for real-time damage detection. This paper presents the preliminary experiments conducted to verify the proposed CNN-based approach.

  • 17.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    University of Michigan, USA.
    Inman, Daniel
    University of Michigan, USA.
    Structural Health Monitoring with Self-Organizing Maps and Artificial Neural Networks2020In: Topics in Modal Analysis & Testing: Proceedings of the 37th IMAC, A Conference and Exposition on Structural Dynamics 2019, Springer, 2020, p. 237-246Conference paper (Other academic)
    Abstract [en]

    The use of self-organizing maps and artificial neural networks for structural health monitoring is presented in this paper. The authors recently developed a nonparametric structural damage detection algorithm for extracting damage indices from the ambient vibration response of a structure. The algorithm is based on self-organizing maps with a multilayer feedforward pattern recognition neural network. After the training of the self-organizing maps, the algorithm was tested analytically under various damage scenarios based on stiffness reduction of beam members and boundary condition changes of a grid structure. The results indicated that proposed algorithm can successfully locate and quantify damage on the structure.

  • 18.
    Avci, Onur
    et al.
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Inman, Daniel
    University of Michigan, USA.
    Vibration suppression in metastructures using zigzag inserts optimized by genetic algorithms2017In: Shock & Vibration, Aircraft/Aerospace, Energy Harvesting, Acoustics & Optics: Proceedings of the 35th IMAC, A Conference and Exposition on Structural Dynamics, 2017 / [ed] Harvie J., Baqersad J., Springer, 2017, p. 275-283Conference paper (Other academic)
    Abstract [en]

    Metastructures are known to provide considerable vibration attenuation for mechanical systems. With the optimization of the internal geometry of metastructures, the suppression performance of the host structure increases. While the zigzag inserts have been shown to be efficient for vibration attenuation, the geometric properties of the inserts affect the suppression performance in a complex manner when attached to the host structure. This paper presents a genetic algorithm based optimization study conducted to come up with the most efficient geometric properties of the zigzag inserts. The inserts studied in this paper are simply cantilever zigzag structures with a mass attached to the unsupported tips. Numerical simulations are run to show the efficiency of the optimization process.

  • 19.
    Balladares, Yandra
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gomez, Matitas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mehmeti, Melis
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utveckling av ett online verktyg för beräkning av träkonstruktioner2019Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    The building sector in Sweden has a big impact on the environment and new methods as well as new technology need to be developed in order to improve the situation. An online tool can be used as an aid in learning and to improve the knowledge. The thesis work comprises the development of an online tool and furthermore an investigation of how other online tools work and how they are designed.The goal and the purpose of the thesis was to create an online tool that can be implemented in the course Steel and Timber Structural Engineering at Linnaeus University. In order to help students with learning and to check calculations.The program that has been developed offers the ability to calculate the load bearing capacity of beams, pillars and connections with metal fasteners. The online tool is in an early stage and needs further. The surveys and interviews gave an insight to what functions need to be implemented in the future.

  • 20.
    Bengtsson, Magnus
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Nilsson, Jens
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Klimatsimulering av ett kyrktorn uppfört i sten2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete syftar till att utreda klimatsimuleringsprogrammen IDA-ICE och WUFI, hur dessa program kan komplettera varandra och användas till simulering av kyrktorn som blivit byggda i sten. IDA-ICE har av tidigare utredningar klargjort att detta program inte redovisa fuktlagring i konstruktioner vilket WUFI gör, därav valet till dessa program. Klimatsimuleringarna utförs i Nässjö gamla kyrkas torn som är byggt av stenblock som sammanfogats med kalkbruk.

    Utredningen görs med hjälp av klimatloggar som mäter temperatur och relativ fuktighet. Dessa mätinstrument placeras ut i Nässjö gamla kyrkas torn för mätning. Värdena för klimatloggarna jämförs med simuleringarnas värden från IDA-ICE och WUFI.

    Klimatsimuleringarna visar sig inte ge samma värden av temperatur eller relativ fuktighet gentemot klimatloggarnas uppmätta värden. Klimatdatan i IDA-ICE skiljer sig mycket från verkligheten vilket bland annat påverkar resultatet. WUFI simulerar endimensionella punkter för konstruktioner vilket innebär att uppbyggnaden av ytterväggarna i programmet inte ger en rättvis bild mot verkligheten, vilket också påverkar resultatet. Resultatet ger därför en bristfällighet till användning av dessa simuleringsprogram, för utredning av klimatet i kyrktorn som är byggda i sten. Det är istället säkrare att använda klimatloggar vid utredningar av klimat, för denna typ av byggnad, då dessa, rätt kalibrerade är tillförlitliga.

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  • 21.
    Briggert, Andreas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fibres orientation on sawn surfaces: Can fibre orientation on sawn surfaces be determined by means of high resolution scanning2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2013 the European journal of wood and wood products published an article regarding a new method to predict strength in structural timber (Olsson et al 2013). By determining the fibres orientation on all four surfaces of each board in sample of timber using a high resolution scanner the authors were able to achieve a coefficient of determination, R2, as high as 0.71 between bending strength and a new indicating property (IP). For the same sample of timber Olsson et al (2013) determined the R2 by axial dynamic excitation as 0.59. However, all boards used in their investigation were planed before scanning. This study examines if a high resolution scanner could be used to determine the fibre orientation on the surfaces of sawn timber boards of Norway spruce. Both band sawn surfaces and circular sawn surfaces were examined. The procedure in this investigation is described as follows. Firstly, both the band sawn and the circular sawn boards were scanned by a WoodEye® scanner and together with dimensions, weight and the first longitudinal resonance frequency, a modulus of elasticity (MOE) profile was calculated for each board. The MOE profiles were calculated according to Olsson et al (2013) i.e. by a transformation matrix based upon the fibres orientation and a compliance matrix based on material parameters for Norway spruce. Secondly, the corresponding MOE profiles were then determined after the boards had been planed. As a result two MOE profiles were determined for each board. An indicating property (IP) was defined as the lowest value along each MOE profile. To compare the results a regression analysis was performed in which the IPs defined before planing worked as predictor variable and IPs defined after planing worked as response variable. The band sawn band boards yielded an R2 = 0.94 and the circular sawn boards an R2 = 0.93. Further the standard error of estimate was SEE = 829.1 MPa and SEE = 640.9 MPa respectively. As a last step in this investigation the SEE values achieved in this study where implemented on to the sample Olsson et al (2013) used in their investigation.

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  • 22.
    Briggert, Andreas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Modelling and strength grading of structural timber and glulam lamellae on the basis of optical scanning and dynamic excitation2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Machine strength grading of sawn timber is a sawmill process in which density, modulus of elasticity (MOE) and bending or tensile strength are predicted such that the timber can be assigned to strength classes. The predictions of these properties are performed using one or several so-called indicating properties (IPs), which represent a board property, or combination of board properties, measured non-destructively. A limitation of today’s strength grading is that the IPs applied in the industry for prediction of strength, in general, are based on rather weak statistical relationships between IPs and strength properties, which in turn results in poor material utilisation. It is well known that the strength of sawn timber is associated with the presence of knots and their surrounding fibre disorientations. Local fibre direction at surfaces of softwood can be determined by means of the light scattering that occur when a wood surface is illuminated by a dot-laser, i.e. by application of the so-called tracheid effect. Lately, IPs based on such measurements have been developed, and some of the suggested IPs have a strong statistical relationship to bending strength. The purposes of the research presented in this thesis are to contribute with knowledge of possibilities and limitations of the tracheid effect and of data of fibre directions in the vicinity of knots, to evaluate if information of fibre directions at surfaces of Norway spruce sawn timber can be used to achieve a better material utilisation of glulam lamellae and finger-jointed timber, and to provide insight regarding the grading regulations in Europe. Results presented herein show that knots and fibre direction within the interior of boards can be modelled on the basis of data obtained by means of the tracheid effect, but also that a previously proposed method to determine out-of-plane fibre angles gives poor accuracy. As regards grading of glulam lamellae, an IP based on fibre directions and dynamic MOE is proposed for prediction of tensile strength. The latter is used when grading glulam lamellae. Application of the proposed IP resulted in substantially increased yield in strength classes. It is also shown that this IP is applicable for boards with sawn as well as with planed surface finish. Regarding current regulations for machine strength grading in Europe, results indicate that grading based on global board properties give higher yield than what is appropriate.

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  • 23.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Hu, Min
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Evaluation of three dimensional fibre orientation in Norway spruce using a laboratory laser scanner2016In: WCTE 2016: World Conference on Timber Engineering, Vienna: Vienna University of Technology , 2016Conference paper (Refereed)
    Abstract [en]

    This paper addresses laser scanning and utilization of the tracheid effect for determination of local fibre orientation, which is decisive for strength and stiffness of timber. A newly developed laboratory laser scanner that can be used for high resolution and high precision scanning of wood surfaces is used for in-depth assessment of a single Norway spruce specimen that contains a knot. It is assumed that the specimen has a plane of symmetry, through the knot, and by splitting the specimen in two parts it is possible to determine fibre orientation on orthogonal planes. Hence, by relying on the assumption of symmetry, the fibre orientation in 3D space can also be determined. The results are used to evaluate the possibility of utilizing the tracheid effect for determination of the out-of-plane fibre angle of an investigated surface. Furthermore, the results are used for verification of a theoretical fibre orientation model that has often been used by researchers.

  • 24.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Modelling 3D orientation of knots in timber on the basis of dot laser scanning and the tracheid effect2015In: / [ed] Josef Eberhardsteiner and Michael Kaliske, 2015Conference paper (Refereed)
    Abstract [en]

    Ongoing research concerns the possibility of determining the 3D orientation of wood fibres within the entire volume of a wooden board using surface information from laser scanning. Previous research, Olsson and Oscarsson [1], has shown that the fibre orientation of side boards can be determined on the basis of such information. The present research is extended to also comprise boards cut from the centre of the log and a first step in this work is to establish 3D models of knots in boards on the basis of information from dot laser scanning of surfaces.

    In comparison with other approaches aiming at 3D models of knots and wood fibre orientation, e.g. Guindos and Guaita[2] and Hackspiel et al. [3], the present model relies to a larger extent on the actual fibre orientation measured on each individual board, rather than on general assumption and mathematical models of typical fibre orientation alone.  

    The fact that all data needed for the model can be sampled in sawmill production speed means that developed models could be used as a basis for advanced strength grading methods, for grading with respect to shape stability and for other purposes of industrial interest.

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  • 25.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Prediction of tensile strength of sawn timber: definitions and performance of indicating properties based on surface laser scanning and dynamic excitation2020In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 53, p. 1-20, article id 54Article in journal (Refereed)
    Abstract [en]

    The presence of wood irregularities such as knots are decisive for the mechanical properties of sawn timber, and efficient utilisation of timber requires methods by which grade determining properties can be predicted with high accuracy. In the glulam and sawmilling industries today, there is a potential and a need for more accurate prediction methods. This paper concerns the performance of a set of indicating properties calculated by means of data from surface laser scanning, dynamic excitation and X-ray scanning, the latter used to obtain boards’ average density. A total number of 967 boards of Norway spruce originating from Finland, Norway and Sweden were used to determine statistical relationships between the indicating properties and the grade determining properties used to grade sawn timber into T-classes. Results show that the indicating properties give coefficients of determination to tensile strength as high as 0.70. Furthermore, results also show that laser scanning of boards with sawn surface finish give basis for almost as accurate grading as what scanning of planed boards do. The results imply that more accurate grading of timber into T-classes is possible by application of a new set of indicating properties. This paper is part one of a series of two papers. In the second paper, two models to derive settings and calculate yield in different strength classes using the indicating properties presented herein are compared and discussed.

  • 26.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Prediction of tensile strength of sawn timber: models for calculation of yield in strength classes2020In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 53, p. 1-15, article id 55Article in journal (Refereed)
    Abstract [en]

    In Europe, strength classes for structural timber and glulam lamellae are defined by minimum requirements of characteristic values of the grade determining properties (GDPs). To fulfill these minimum requirements of characteristic values in the daily production at sawmills, indicating properties (IPs) to GDPs are calculated for each board and based on predetermined limits of the IPs (settings) boards are assigned to the graded class, or rejected. The aims of this paper is to address and discuss two different grading procedures/models that can be applied when settings for IPs that reflects a local board property are derived and to show how the yield in different T-classes depend on the model applied. It is not always that a board’s weakest cross-section is evaluated in a destructive test. An IP representing a local board property can therefore be determined either as the lowest property of the tested part of the board or as the lowest property along the whole board when applied to derive settings. Results presented in this paper show that too low settings and too large yields are obtained when the latter IP is employed. Similarly, IPs reflecting a global board property, like axial dynamic MOE, also give too low settings and too high yield in strength classes. This paper is the second and closing part of a series of two paper on prediction of GDPs and procedures for grading sawn timber into T-classes.

  • 27.
    Briggert, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Three dimensional knot models based on surface laser scanning2015In: Proceedings 19th International Nondestructive Testing and Evaluation of Wood Symposium Rio de Janeiro, Brazil, 23-25 September, 2015. / [ed] Ross, Robert J.; Gonçalves, Raquel; Wang, Xiping,, Madison, USA: USDA, Forest Service, Forest Products Laboratory , 2015, Vol. 19, p. 83-90Conference paper (Refereed)
    Abstract [en]

    Most machine strength grading methods of today result in limited grading accuracy and poor yield in higher strength classes. A new and more accurate grading method utilizing laser scanning technique to determine the in-plane fibre directions on board surfaces was recently approved for the European market. In this, however, no consideration is taken to the out-of-plane direction of the fibres. A first step towards scanning-based 3D models of the fibre orientation is the establishment of 3D knot models. In this investigation laser scanning was used to identify knot surfaces on longitudinal board surfaces. By means of developed algorithms knot surfaces that belonged to the same physical knot visible on different sides of the board were identified. All knots with surface areas larger than 100 mm2 were correctly identified and modeled in 3D. This is a promising starting point for further development of the new grading method based on laser scanning.

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  • 28.
    Catbas, Catbas
    et al.
    University of Central Florida, USA.
    Celik, Ozan
    University of Central Florida, USA.
    Avci, Onur
    Qatar University, Qatar.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Gul, Mustafa
    University of Alberta, Canada.
    Do, Ngoan
    University of Alberta, Canada.
    Sensing and monitoring for stadium structures: a review of recent advances and a forward look2017In: Frontiers in built environment, E-ISSN 2297-3362, Vol. 38, no 3Article in journal (Refereed)
    Abstract [en]

    Stadiums like those used for sporting or concert events are distinct from other civil engineering structures due to several different characteristics. Some challenges mainly originate from the interaction with the human factor, as stadiums are subjected to both synchronized and random motion of large crowds. The investigations in the literature on this topic clearly state that stadiums designs are in urgent need of more reliable load quantification and modeling strategies, deeper understanding of structural response, generation of simple but efficient human–structure interaction models, and more accurate criteria for vibration acceptability. Although many esthetically pleasing and technologically advanced stadiums have been designed and constructed using structurally innovative methods, recent research on this field still calls for less conservative and more realistic designs. This article aims to highlight the recent advances in this field and to provide a follow-up to the literature review covering until 2008 (Jones et al., 2011a) on vibration serviceability of stadiums structures. The article will also discuss new sensing and monitoring techniques on load-time history measurements and their regeneration, as well as crowd motion, stadium health monitoring, and human comfort analysis. Operational effects of crowds on the dynamic properties are also discussed. The article concludes with a forward look on the recommended work and research for dynamic assessment of stadiums.

  • 29.
    Dahl, Arvid
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lindström, Charlie
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mekanisk prestanda hos traditionella träfogar kontra samtida byggbeslag2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Societies demand for environmentally friendly and sustainable construction is ever increasing. One way to meet these new demands on environmentally friendly construction is to use more wood which decreases carbon emissions through the substitution effect. This report aims to research whether traditional joinery techniques entirely executed in wood can replace contemporary joinery techniques in future construction. The goal is to show whether this is possible from a strength standpoint. The research will be limited in that it will strictly seek to study a pillar-beamconnection where the traditional joint researched will be three varying mortise and tenon joints and the contemporary joint is a joist hanger. The joints will be analyzed with calculation and experimentation where the load case aims to produce mainly shear in the joint. The results point towards it being possible to introduce this traditional joint in contemporary construction.

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    Mekanisk prestanda hos traditionella träfogar kontra samtida byggbeslag
  • 30.
    Do, Ngoan T.
    et al.
    University of Alberta, Canada.
    Gül, Mustafa
    University of Alberta, Canada.
    Abdeljaber, Osama
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Novel framework for vibration serviceability assessment of stadium grandstands considering durations of vibrations2018In: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 144, no 2Article in journal (Refereed)
    Abstract [en]

    Annoying vibrations in grandstand structures have been receiving more attention due to the increasing slenderness of the architectural components and the complexity of the crowd loading for engineers. The vibration serviceability checks under these conditions become a challenge in the design and operation stages. Regarding human comfort, excessive vibrations due to occupant activities may affect comfort and/or cause panic, especially for passive occupants who do not participate in generating excitations. Although durations of excessive vibrations have been considered as one of the most important factors affecting occupant comfort, incorporating the vibration duration in the occupant comfort analysis has not been addressed yet. In addition, the currently available approaches using raw acceleration, weighted RMS acceleration, vibration dose values (VDV), and so on may not always be sufficient for serviceability assessment due to the lack of guided procedure for calculating the integration time and implementing the duration of vibration into the process. Therefore this study proposes a new parameter and framework for assessing human comfort which incorporates the duration of vibration with conventional data processing. The aim is to better examine vibration levels and the corresponding occupant response focusing on grandstand structures. A new parameter, the area of RMS (ARMS), is introduced using the running RMS values of acceleration weighted by the frequency weighting functions. Furthermore, perception ranges for human comfort levels based on the proposed parameter are presented. The experimental study reveals that the proposed framework can successfully address the impact of duration time on determining the levels of vibrations and comfort using the proposed parameter.

  • 31.
    Edvardsson, Ida
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Martinsson, Ida
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jämförelse mellan beräknad och verklig energiförbrukning på Östra Lugnet2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Undersökningen som görs i det här examensarbetet följer upp energianvändningen på delar av området Östra Lugnet i Växjö. Energianvändningen jämförs mot de energikrav som BBR och Växjö kommun ställer.

    Arbetet tar också fram differenserna mellan faktisk och beräknad energianvändning, utifrån den specifika energianvändningen för bostäderna för år 2015. De differenser som resultatet visar jämförs sedan mot olika faktorer som kan påverka att det finns en skillnad. De faktorer den här undersökningen studerar närmare är framförallt energiberäkningsprogrammen som används i projekteringen, men också boendevanor och vad för typ av människor som brukar bostäderna.

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  • 32.
    El-Homsi, Patric
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fredrik, Bramstedt
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Energikartläggning av ett bostadshus från 20162018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The building in this survey was completed in October 2016 and is located at Kvarnvägen 31 in Gemla. The purpose of the study is to map the energy consumption and determine whether the installation of solar collectors is beneficial or not. The goal is to map the energy use in the building, report improvement measures and analyse the technical installations.

    The qualitative methods consisted of a study visit, site visits, review of drawings and an ocular survey of the building with a thermal camera. In order to calculate and analyse the building´s energy use, modelling of the building envelope components and technical installations were performed in VIP-Energy.

    The results of the energy survey shows that the calculated energy use for the building is similar to the projected energy use and the energy declaration places the building in energy class B. Many factors are of significant importance in optimizing solar collectors such as inclination angle, orientation and installation type. Having solar collectors installed proved to be beneficial both in terms of energy and cost if they are connected as proposed. HSB FTX is theoretically advantageous for both preheating of supply air and defrosting of the building's ventilation system.

    The enhancement proposals are to adjust the inclination angle of the solar collectors and to reconnect the heat input obtained from the solar collectors.

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  • 33.
    Elvingson, Vera
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Generationsboende – ett anpassat flerbostadshus där alla generationer kan trivas2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten omfattar en utredning av intresset för den nya boendeformen generationsboende, som är ett flerbostadshus anpassat för att alla generationer ska kunna bo och trivas. Bostadsbrist råder på många platser i Sverige. Befolkningen åldras och behöver tillgänglighetsanpassade alternativ till att bo kvar i sitt gamla boende eller flytta in på ett boende med bara andra äldre. Unga behöver hjälp ut på bostadsmarknaden och småbarnsfamiljer behöver ett boendealternativ som kan spara dem tid.

    Syftet är att utreda hur ett generationsboende på bästa sätt bör utformas och målet är att ta fram ett förslag baserat på den data som samlats in. Data samlades in genom informationssökning, enkäter, djupintervjuer och studiebesök. Resultatet visade att den önskade gemenskapen med grannarna låg på 5,37 på en tiogradig skala och att det var viktigt att lägenheterna var klimateffektiva och kvadratoptimerat utformade med bra ljusinsläpp. Gemensamma utrymmen väckte stort intresse hos respondenterna men vilka typer av utrymmen som föredrogs varierade beroende på ålder.

    Slutligen ritades ett förslag på ett generationsboende upp baserat på resultaten. Slutsatsen är att ett generationsboende är en god idé då det fick bra respons.

  • 34.
    Eriksson, Christoffer
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Implementering av färgfilosofi i bostäder2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Arbetet behandlar färgers betydelse för att förbättra bostadskvalité genom att implementera specifika färger i bostadens interiöra väggar till samtliga rum. Rummen i bostaden har olika funktioner. Funktionerna kan förbättras genom tillämpning av färgers psykologiska egenskaper. En ökad bostadskvalité leder till ökat välbefinnande hos individer och är en av många faktorer som påverkar den sociala, ekologiska och ekonomiska hållbarheten i samhället.

    Arbetets förslag tas fram genom studiens enkätundersökning som underlag. Enkätundersökningen grundar sig i färgteorier och dess psykologiska egenskaper. Resultaten visar att det finns en okunskap om färgers funktionella betydelse i bostaden och att individer ändrar sina färgval efter förmedlad kunskap. Förslaget bör ses som rekommendationer till färgsättning på interiöra väggar i förhållande till rummets funktion.

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  • 35.
    Gustafsson, Fredrik
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Industriell Ekonomi.
    Söderström, Henrik
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Industriell Ekonomi.
    Industriellt synsätt på värdeflödet vid anläggningsarbeten genom visuell styrning2016Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att studera vilka möjligheter arbetsledningen på svenska byggföretag har, att på ett effektivare sätt styra värdeflödet av resurser med visuell styrning. Målet med studien är att identifiera förbättringsförslag och fördelar som finns och som kan skapas med visuell styrning för arbetsledningen vid anläggningsarbeten.Studien bygger på mätningar som har genomförts på ett anläggningsarbete av en cirkulationsplats i Ullared under 7 dagar där Skanska AB var entreprenör.Under mätningarna har författarna tagit fram fördelar och förbättringsförslag som finns eller kan skapas med visuell styrning. Slutsats och diskussion ska ge en indikation till svenska byggföretag om vad de kan göra för att tillgodogöra sig framstegen från tillverkningsindustrin.

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    Examensarbete i Industriell Ekonomi vid Linnéuniversitetet VT16 16-06-2016 Fredrik Gustafsson & Henrik Söderström
  • 36.
    Haavik, Trond
    et al.
    Segel As, Norway.
    Tommerup, Henrik
    Technical University of Denmark.
    Svendsen, Svend
    Danish Technical University, Lyngby, Denmark.
    Paiho, Satu
    VTT, Espoo, Finland.
    Ala-Juusela, Mia
    VTT, Espoo, Finland.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Gustavsson, Leif
    Mid Sweden University.
    Aabrekk, Synnøve
    Segel As, Norway.
    Næsje, Peik
    Mlecnik, E.
    Cré, Johan
    Vrijders, Jeroen
    New business models for holistic renovation solutions of single family houses2011Conference paper (Refereed)
    Abstract [en]

    Single family houses represent the biggest potential for energy savings within residential buildingsin the Nordic countries. In earlier research project [1] it highlighted that there is a missing linkbetween the single family house owner and various segregated offers of single solutions forrenovation and/or energy efficiency installations. In the two international research projectsSuccessFamiles and One Stop Shop, establishment of new business models as pilots for bridgingthis gap are now being monitored.Two of the pilots as “one stop shops”, a retailer chain in Finland and a daughter company of aNorwegian manufacturer of insulation, are described and discussed.A key issue for any business model which offers an integrated service from analysis of the houseand recommendations for measures is the trustworthiness of the supplier.As a holistic energy efficient renovation project is a “new” and unknown service to single familyhouse owner and at same time a costly investment, it is important for the suppliers to findadequate ways of communicating through each phase of the buying process. There are variouschallenges in each of the phases which have to be solved differently.

  • 37.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Comparing the profitability of various renovation packages in Swedish residential building sector: case study2019In: Sustainable built environment conference (SBE 2019). 6-7 August, Tokyo, Japan, 2019Conference paper (Refereed)
    Abstract [en]

    Swedish government adopted national targets to reduce total energy consumption and mitigate environmental impacts. At this point, detached houses play an important role, since they account for a large share of dwelling stock in this country. The majority of these buildings are affected by technical deteriorations in building envelopes and heating, ventilation and air condition systems. Accordingly, there is a need for a deep renovation strategy, which covers both energy efficiency measures and economic issues. Additionally, a deep renovation can improve indoor climate, which contributes to the enhanced health and wellbeing. Thus, the aim of this study is to compare the efficiency of eight different renovation packages in reducing energy consumption and providing economic benefits in a detached house in Sweden. The renovation packages include 1) improving the U-value of building envelopes; 2) adding a heat recovery for ventilation system; 3) installing a ground source heat pomp for supporting heat demand and domestic hot water; 4) combination of renovation package 1 and 2; 5) combination of renovation package 1 and 3; 6) combination of renovation package 2 and 3; 7) combination of renovation package 1, 2 and 3; and 8) combination of renovation package 1, 2, 3 along with installing photovoltaic cells for producing electricity. The reduction in energy consumption was calculated in kWh/m². year for each renovation package, while the economic benefit was obtained by calculating the payback period during a lifespan of 50 years and internal rate of return with interest rates of 1%, 3% and 6%. The results indicate that renovation package 8 has the highest potential in reducing total energy consumption, while renovation package 3 is the most profitable solution since it provides the shortest payback period with the highest internal rate of return. The results help to define and project efficient energy policies in Sweden.

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  • 38.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Pardalis, Georgios
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Vadiee, Amir
    Mälardalen University, Sweden.
    Profitability of various energy supply systems in light of their different energy prices and climate conditions2020In: Buildings, ISSN 2075-5309, E-ISSN 2075-5309Article in journal (Refereed)
    Abstract [en]

    The majority of the single-family houses in Sweden are affected by deteriorations in building envelopes as well as heating, ventilation and air conditioning system. These dwellings are therefore in need of extensive renovation, which provides an excellent opportunity to install renewable energy supply systems to reduce the total energy consumption. The high investment costs of the renewable energy supply systems was previously distinguished as the main barrier in the installation of these systems in Sweden. House-owners should therefore compare the profitability of the energy supply systems and select the one, which will allow them to reduce their operational costs. This study analyses the profitability of a ground source heat pump, photovoltaic solar panels, and an integrated ground source heat pump with a PV system, as three energy supply systems for a single-family house in Sweden. The profitability of the supply systems was analysed by calculating the payback period (PBP) and internal rate of return (IRR) for these systems. Three different energy prices, three different interest rates, and two different lifespans were considered when calculating the IRR and PBP. In addition, the profitability of the supply systems was analysed for four Swedish climate zones. The analyses of results show that the ground source heat pump system was the most profitable energy supply system, since it provided a short PBP and high IRR in all climate zones when compared with the other energy supply systems. Furthermore, results show that increasing the energy price improved the profitability of the supply systems in all climate zones.

  • 39.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Pardalis, Georgios
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Vadiee, Amir
    Mälardalen University, Sweden.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Profitability of various energy supply systems when renovating a single-family house in Sweden: case study2019In: International Conference on Applied Energy (ICAE 2019). August 12-15, Västerås, Sweden, 2019Conference paper (Refereed)
    Abstract [en]

    The majority of single-family houses in Sweden are affected by deteriorations in building envelopes as well as heating, ventilation and air conditioning systems, since they are about 30 years old. Theses house are therefore in need of extensive renovation, which provides an excellent opportunity to incorporate energy efficiency measures to reduce both the energy consumption and also operational. Although former studies analyzed the cost effectiveness of various renovation packages, they mainly excluded the evaluation of energy price implications on cost effectiveness of different renovation package in Sweden. Accordingly, this study considers three energy prices and quantifies the payback period (PBP) and internal rate of return (IRR) of the packages, when renovating a single-family house in Sweden. The renovation packages included three distinct energy supply systems, commonly installed when implementing energy renovations: ground source heat pump (GSHP), photovoltaic solar panels (PV), and an integrated GSHP and PV system. The analyses of results show that a the GSHP system provides higher IRR and the lowest PBP compared to the other two renovation packages, due to its high performance in reducing energy consumption and its relatively low investment cost. Furthermore, results show that raising the energy price can increase the IRR and reduce the PBP of the renovation packages and respectively. Moreover, increasing the interest rate adds on PBP of renovation packages, since it depreciates the cost for saved energy. 

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    Abstract
  • 40.
    Jalilzadehazhari, Elaheh
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Vadiee, Amir
    Mälardalen University, Sweden.
    Johansson, Peter
    Jönköping University, Sweden.
    The profitability of various energy supply systems considering variations in future climate conditions2019In: International Conference on Applied Energy (ICAE 2019). August 12-15, Västerås, Sweden, 2019Conference paper (Refereed)
    Abstract [en]

    Ambitious targets were set in Sweden to increase the share of renewable energy resources and reduce greenhouse gas emissions. Renovating old detached houses can assist in achieving the abovementioned targets, since they make up a great share of the final energy consumption and carbon dioxide emissions in Sweden. Although, several attempts were taken to improve the energy performance of the detached houses, the implementation of energy efficient renovation is yet low due to mainly high investment cost. Former studies evaluated the cost effectiveness of various energy efficient renovations in renovating detached houses in Sweden, but they provided no information how possible climate futures affect the determination and adoption of energy efficiency policies, such as monetary instruments. Accordingly, this study considered three distinct energy renovation packages and analyzed the subsidies required for implementing renovation packages for given interest rates and lifetimes. Furthermore, three different climate scenarios were considered to analyze the effect of possible climate futures on subsidies required. The analyses of results show that increasing the lifetime have greater impact on required subsidies than increasing the interest rate. Furthermore, the results show that variation in future climate conditions changes the required subsidies when implementing energy efficiency renovations. Results can be used as an aid when adopting energy efficiency policies. 

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    Abstract
  • 41.
    Jensén, Nils
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Alfsson, Sofia
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vad tjänar att hyckla,tids nog får man cykla: Att skapa goda förutsättningar för cykeltrafiken på Växjö stationsområde2014Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete syftar till att utreda vilka faktorer som möjliggör ökade flöden av cykeltrafik på Växjö stationsområde. Arbetets genomförandemoment utgår i aktuell teori och forskning inom området.

    Utifrån Växjös ambitiösa miljömål och vilja att skapa goda förutsättningar för cyklister (tillsammans med projektledningens önskemål om förslag på detta) bedöms ett stort behov finnas av att hitta lämpliga platser för nya cykelparkeringar och en byggnation av ett nytt cykelgarage. Placeringen för cykelgaraget kommer att utgå från de visioner och planer som finns för tidigare nämnd ombyggnation på Växjö stationsområde.

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    Rapport
  • 42.
    Johansson, Marie
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Blom, Åsa
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Expert competence for sustainable timber engineering: a master program in close cooperation between industry and academia2014In: WCTE 2014 - World Conference on Timber Engineering, Proceedings, 2014Conference paper (Refereed)
    Abstract [en]

    From a legislative point of view it has been possible to build timber buildings with arbitrary number of storeys in Sweden during almost two decades. Several buildings up to eight storeys have been completed during that time, but the competence for planning and building such structures are limited to a handful of actors. This fact has been recognized by funders of research/education and an educational program for spreading the knowledge within the industry led by Linnaeus University is financed since about two years. Particularly interesting in the programme is that the courses are developed in cooperation between the industry and the academia. The courses are to fulfil needs with respect to knowledge, but also with respect to format so that the main target group, skilled engineers within the industry, can find the motivation to follow a course or lager parts of the program.

  • 43.
    Karakas, Berhan
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Stempnik, Aleksandra
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Framtagning av bedömningsmall av produktleverantörer i stålbyggnadsbranschen: Fallstudie på Llentab AB2017Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Inköp och leverantörsval påverkar företags konkurrenskraftighet. För att behålla sin position på marknaden och skapa långsiktiga relationer måste företag välja rätt partnerföretag. Företag kan uppnå sitt mål med leverantörsrelationer med hjälp av begränsat antal samarbetspartner, rätt bedömning och segmentering av leverantörer.

    Inköpsprocess och bedömningsmetod studerades på ett fallföretag för att erhålla information om ett nuvarande läge som sedan med hjälp av teori kunde operationaliseras och analyseras. Detta görs i huvudsak med hjälp av Multi-Criteria Decision Making, Kraljic matris och inköpspolicy.

    Resultatet presenterades med hjälp av sex leverantörer. För att leverantörerna ska vara godtagbar skall alla ‘obligatoriska’ krav uppfyllas i inköpspolicyn och erhålla ett önskat läge i Kraljic matris.

    Nyckelord: Kraljic matris, leverantörsbedömning, standardiserad bedömningsmall, inköpsprocess, Multi-Criteria Decision Making, Analytical Hierarchical Process, BFP-Bedömningsmall för produktleverantörer.

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  • 44.
    Karlsson, Ellen
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Rönnbäck, Maria
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Den offentliga miljöns inverkan på trygghet och social hållbarhet i ett särskilt utsatt område2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study is analyzing how well executed community planning might minimize crime and increase safety in segregated city areas. The importance of actively involving citizens in decision making is vital to achieve social sustainability in a community. The purpose of the study is to create an exemplifying idea of how the district area could develop and excel in a positive way. The study is based on opinions from adolescents living in the area in question and will be compared and used in relation to police officers needs to be able to do their job in the area. To reach the results, workshops with the adolescents and an interview with a police officer took place. The goal is to develop an example of how to minimize crime in a segregated city district.

    The proposal of how to design the area is focused on the need for lighting, openness and sightlines as is asked for. It also includes places to gather, which also is needed in the area. The study can be used to form ideas of ways to form public spaces in socially problematic areas.

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  • 45.
    Koubek, Radek
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dedicova, Karolina
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Friction of wood on steel2014Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    This thesis deals with the experimental description of friction between steel and wood materials, specifically laminated veneer lumber (LVL) and pine wood with two types of annual rings. It studies the influence of a number of different parameters on the coefficient of friction such as contact pressure, moisture content, fiber orientation in relation to the load direction, steel surface roughness, and horizontal load rate. First, the theoretical mechanical and physical properties as well as the coefficient of friction itself are described. This is followed by the description of the test setup including the test method and how the obtained data is exported, handled and processed and how the coefficient of friction is determined.

    The results study the influence of different parameters and show that the coefficients of friction for the smooth sliding plate tests vary in between 0.1 and 0.3, whereas tests with the rough sliding plate vary around 0.7.

    Factors influencing the coefficient of friction were found to be the different moisture content under all tested pressures, the different fiber direction under low contact pressure, the contact pressure itself, though under higher pressures the influence was found to be low, and the horizontal load rate under low pressures. The outcomes are further discussed in the discussion chapter.

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  • 46.
    Larsson, Beatrice
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Bergman, Adam
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Korslimmat trä av sidobrädor: En hållbar framtid2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Korslimmat trä, KLT, är byggelement av trä vars efterfrågan ökat de senaste åren och som fortsätter öka. Därför ligger det i sågverksindustrins intresse att kunna använda sig av billigt råmaterial i konstruktionen av KLT-elementen då skulle öka lönsamheten för sågutbytet. Syftet med detta arbetet är därför att konstruera och pröva hållfasthets- och styvhetsegenskaper för KLT-element konstruerade med ej hållfasthetsklassade sidobrädor. Idag får nämligen bara hållfasthetsklassade brädor används i konstruktionen. I detta arbetet prövas två olika konstruktioner av KLT-element i böjtest vilka båda visar goda resultat för de studerade hållfasthets- och styvhetsparametrarna. De uppnådda värdena för parametrarna jämförs med teoretiskt beräknade värden för ett KLT-element av råmaterial med hållfasthetsklassen C24. Variation finns dock mellan de olika testelementen vilket är en orsak av att trä är ett heterogent material. Värdena mellan olika testelement skiljer ibland markant. Däremot visar till och med det testelement med sämst hållfasthets- och styvhetsegenskaper högre värden för de studerade parametrarna än de teoretiskt beräknade. Därför kan sidobrädor som råmaterial till KLT-produkter konstateras som ett bra konstruktionsmaterial.

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  • 47.
    Lindblad, Fredrik
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Summary of research result from the “City development project Torparängen”2019Report (Other academic)
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  • 48.
    Linderholt, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Olsson, Jörgen
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Combining testing and calculation for of low frequency sound and vibrations in timber buildings2018In: Forum Wood Building Nordic 2018, 27-28 September 2018, Växjö, Sweden, 2018Conference paper (Other (popular science, discussion, etc.))
  • 49.
    Mahapatra, Krushna
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Nair, Gireesh
    Department of Engineering and Sustainable Development, Mid Sweden University.
    System analysis of and stakeholders’ perceptions on end-use energy efficiency measures for existing Swedish multi-family buildings2012In: COBEE 12, International Conference on Building Energy and Environment. Boulder, Colorado, USA, August 1-4, 2012Conference paper (Refereed)
    Abstract [en]

    In Sweden, there is opportunity to implement energy efficiency measures in about one million existing apartments that are likely to be refurbished within the next 20 years. System analyses of installation of energy efficient windows, and increased insulation in attic and in exterior walls for an existing multi-story building showed that the primary energy savings for the measures depend on the energy supply system. Energy efficiency potential was higher with installation of efficient windows than improved attic insulation. Responses of 673 chairpersons of co-operative hosing associations to a mail-in survey in 2010 also showed that greater proportion of respondents perceived that energy efficient windows had advantages over insulation improvements. However, majority had no intention to implement such measures during next 10 years and economic factors guide their decisions. Lack of expertise to assess the benefits of energy efficiency measures was the most cited hindrances to energy efficiency investments.

  • 50.
    Mainali, Brijesh
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Pardalis, Georgios
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Criteria based approach for assessment of policy instruments for deep renovation of residential building in the Netherlands2019In: ECEEE Summer Study proceedings: eceee 2019 Summer Study on energy efficiency: Is efficient sufficient?, European Council for an Energy Efficient Economy (ECEEE), 2019, p. 599-606, article id 3-352-19Conference paper (Refereed)
    Abstract [en]

    The building sector is responsible for more than 40 % of the energy use and 32 % of carbon dioxide emissions in the European Union (EU). Previous research has shown that the present rate of energy retrofit and refurbishment in Europe is far below (<50 %) than that is required to meet the EU's building related energy efficiency goals for 2020. Appropriate policy interventions for deep renovation is perceived as a catalytic agent in promoting energy efficiency and leveraging more investments in the building sector. EU directives regarding Energy Efficiency reflects in various member states' national targets and policy measures to improve the energy performance of the existing building stocks. Economic policy instruments seem to be influential in steering the deep renovation market, but this alone may not be sufficient for the sustainable growth of the market. There is a need for market-based approach to enhance the private sector involvement, both in terms of technical and financial capabilities. This paper evaluates the policy instrument used for promoting deep renovation of residential buildings in the Netherlands. A "Theory-based evaluation" technique has been used in analyzing the content of the policy instrument, and the underlying theories and policies, at output and impact level. A set of the evaluation criteria have been applied for assessing such policy instruments in leveraging energy efficiency investments and their effectiveness in terms of energy savings. The assessments are done based on the meta-analysis of relevant literature and data sources, and finalized in consultation with the Dutch partners from INNOVATE (Integrated solutions for ambitious energy refurbishment of private housing) project under Horizon 2020. Further, the challenges for scaling up such existing effort for the sustainable growth of the deep renovation market has been explored.

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