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Linderholt, A. & Olsson, J. (2018). Combining testing and calculation for of low frequency sound and vibrations in timber buildings. In: Forum Wood Building Nordic 2018, 27-28 September 2018, Växjö, Sweden: . Paper presented at Forum Wood Building Nordic 2018, 27-28 September 2018, Växjö, Sweden.
Open this publication in new window or tab >>Combining testing and calculation for of low frequency sound and vibrations in timber buildings
2018 (English)In: Forum Wood Building Nordic 2018, 27-28 September 2018, Växjö, Sweden, 2018Conference paper, Oral presentation only (Other (popular science, discussion, etc.))
Keywords
Impact sound, simulations, measurements
National Category
Other Civil Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering; Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-78076 (URN)
Conference
Forum Wood Building Nordic 2018, 27-28 September 2018, Växjö, Sweden
Available from: 2018-09-28 Created: 2018-09-28 Last updated: 2018-10-04Bibliographically approved
Landel, P., Linderholt, A. & Johansson, M. (2018). Dynamical properties of a large glulam truss for a tall timber building. In: : . Paper presented at 2018 World Conference on Timber Engineering, August 20 - 23, 2018 i Seoul, Republic of Korea. , Article ID S747.
Open this publication in new window or tab >>Dynamical properties of a large glulam truss for a tall timber building
2018 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

When designing a tall timber building, the accelerations due to wind loads are in many cases decisive. The parameters governing the dynamic behaviour of the building are the structure’s stiffness, damping and mass together with the loads. The first two parameters are not well-known during the serviceability limit state of timber structures generally and of timber connections specifically.

In this study, dynamical properties of a large glulam truss, a part of the vertical and horizontal structural system in a residential six-storey timber building, are estimated from measurements made in the manufacturing plant. The timber members of the truss are joined with slotted-in steel plates and dowels. Forced vibrational test data are used to extract the dynamical properties. Finite element (FE) models, supported by the experimental results, were developed and simulations, to study the influence of the connection stiffnesses on the total behaviour, were performed. The vibration test results of measurements made on separate structural parts give valuable input to model timber structures and better possibilities to simulate the dynamic behaviour of tall timber buildings as well as the load distribution in wooden structures in the serviceability limit state.

Keywords
Vibrational testing, experimental modal analysis, stiffness and damping, timber joints, slotted-in steel plates with dowels connection
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering; Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-76789 (URN)
Conference
2018 World Conference on Timber Engineering, August 20 - 23, 2018 i Seoul, Republic of Korea
Projects
Tall Timber Buildings – concept studies
Funder
Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, 942-2015-115
Available from: 2018-07-11 Created: 2018-07-11 Last updated: 2018-09-03Bibliographically approved
Olsson, J. & Linderholt, A. (2018). Low-frequency impact sound pressure fields in small rooms within lightweight timber buildings - suggestions for simplified measurement procedures. Noise Control Engineering Journal, 66(4), 324-339
Open this publication in new window or tab >>Low-frequency impact sound pressure fields in small rooms within lightweight timber buildings - suggestions for simplified measurement procedures
2018 (English)In: Noise Control Engineering Journal, ISSN 0736-2501, E-ISSN 2168-8710, Vol. 66, no 4, p. 324-339Article in journal (Refereed) Published
Abstract [en]

Low-frequency impact sound insulation, down to 20 Hz, has a significant effect on humans' dissatisfaction due to noise in timber buildings. Today, the low-frequency procedure of the ISO 16283-2:2015 impact sound measurement standard covers the frequency range down to 50 Hz for the use of an ISO tapping machine, but does not yet cover the use of an ISO rubber ball. Here, microphone grid measurements were made in two small rooms that were excited by an ISO rubber ball from the rooms above. In each grid, 936 microphone positions were used to capture data representing the full spatial fields of impact sound pressures from 10 to 500 Hz for one excitation location for each room. The data show that the positions at the radiating ceiling surfaces have low maximum sound pressure levels compared to the pressure levels at the floors, especially in the floor corners. First, a measurement procedure to predict the maximum exposure of low-frequency sound in a room is proposed It is suggested that the maximum values for each frequency band in the corners opposite to the partition being excited (i.e., the floor corners) be used. Second, a procedure to predict the room average sound pressure level and the prediction's normal distribution is suggested. Iterative measurements with random microphone locations and random excitation locations are used. The advantage of this method is that the required precision and information about the sensitivity due to different excitation points are obtained. (c) 2018 Institute of Noise Control Engineering.

National Category
Mechanical Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-77898 (URN)10.3397/1/376628 (DOI)000444002100004 ()
Available from: 2018-09-20 Created: 2018-09-20 Last updated: 2018-09-20Bibliographically approved
Olsson, J. & Linderholt, A. (2018). Measurements of low frequency impact sound transfer functions of light weight timber floors, utilizing the ISO rubber ball. In: Proceedings of the 25th International Congress on Sound and Vibration: . Paper presented at ICSV25, 25th International Congress on Sound and Vibration, Hiroshima, Japan, July 8-12, 2018 (pp. 1-8). The International Institute of Acoustics and Vibration
Open this publication in new window or tab >>Measurements of low frequency impact sound transfer functions of light weight timber floors, utilizing the ISO rubber ball
2018 (English)In: Proceedings of the 25th International Congress on Sound and Vibration, The International Institute of Acoustics and Vibration , 2018, p. 1-8Conference paper, Published paper (Other academic)
Abstract [en]

Impact sound below 100 Hz is an important issue for light weight timber buildings. It is also well known that finite element model simulations are more beneficial in the low frequency range than in higher frequencies due to the longer wavelengths allowing the element meshes to be coarser. Utilizing transfer functions to describe impact sound would imply simplifications to correlate data stemming from measurements and low frequency finite element models. If the impact force is known, the simulations become easier since there would not be any need for the modelling of the impact mechanisms, just calculations of the transfer functions which are then combined with the force spectrum to give the resulting sound pressure. The impact ball has shown to be in close resemblance with a human's excitation in the low frequency range which makes it a suitable excitation device. However, when its force spectrum is needed, it may be hard in practice to achieve that during a regular measurement since the ball is not easily equipped with a force gauge. Here, two different methods are investigated. An investigation of the repeatability of the force spectrum of the rubber ball in the low frequency range for floors having different mobilities is made. To enable this, an equipment for field measurements of impact force spectrum and potentially point mobilities using an ISO ball, is designed, manufactured and evaluated. Impact force measurements are made on lightweight timber as well as concrete floors, with different properties for comparisons. Within the lowest frequencies it is potentially possible to use one given force spectrum from the ISO ball together with impact sound measurements for the creation of impact force to sound transfer functions on different floors.

Place, publisher, year, edition, pages
The International Institute of Acoustics and Vibration, 2018
Keywords
impact sound, low frequency, ball, transfer functions, timber, floors
National Category
Fluid Mechanics and Acoustics
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-73802 (URN)
Conference
ICSV25, 25th International Congress on Sound and Vibration, Hiroshima, Japan, July 8-12, 2018
Projects
Urban Tranquillity
Funder
Interreg Öresund-Kattegat-Skagerrak
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-09-03Bibliographically approved
Kodakadath Premachandran, R., Linderholt, A., Håkansson, L. & Gothberg, M. (2018). Numerical 1D and 3D models representing a DTH drilling system: A comparison of accuracy and computational speed. In: The International Institute of Acoustics and Vibration , 2018. (Ed.), Proceedings of the 25th International Congress on Sound and Vibration, The International Institute of Acoustics and Vibration , 2018: . Paper presented at The International Institute of Acoustics and Vibration , 2018. International Institute of Acoustics and Vibration (IIAV)
Open this publication in new window or tab >>Numerical 1D and 3D models representing a DTH drilling system: A comparison of accuracy and computational speed
2018 (English)In: Proceedings of the 25th International Congress on Sound and Vibration, The International Institute of Acoustics and Vibration , 2018 / [ed] The International Institute of Acoustics and Vibration , 2018., International Institute of Acoustics and Vibration (IIAV) , 2018Conference paper, Published paper (Refereed)
Abstract [en]

The drilling industry is steadily moving towards automation. To have a better control over the drilling operation and to optimize the drilling performance, it is necessary to have a good understanding of the physics involved in the process. A good simulation model of the drilling process/system would be of great value in assisting this and in enabling the development of strategies to optimize it. A representative simulation model can provide insights into various phenomena that appear during drilling for different drilling conditions. Such a model is also likely to be of assistance in preparing various measurements. Issues such as choosing the type of sensors, their positions and which quantities to measure are supported by a model. A well calibrated model in combination with information extracted from measured data are hence likely to assist in selecting control strategies for optimized drilling performance. In this paper we present a MATLAB based 1D simulation model of a Down The Hole (DTH) drill and compare it with an existing 1D model in terms of computational speed and accuracy. The emphasis is to make a 3D model of a DTH system that is computationally efficient and accurate.

Place, publisher, year, edition, pages
International Institute of Acoustics and Vibration (IIAV), 2018
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-73954 (URN)
Conference
The International Institute of Acoustics and Vibration , 2018
Note

Ej belagd 181017

Available from: 2018-05-05 Created: 2018-05-05 Last updated: 2018-10-17Bibliographically approved
Linderholt, A. & Olsson, J. (2017). A simulation based study of low frequency transient sound radiation from floors: a concrete vs. a hybrid floor. In: Proceedings of the 24th International Congress on Sound and Vibration: . Paper presented at The 24th International Congress on Sound and Vibration (ICSV), London, 23-27 July, 2017. Curran Associates, Inc.
Open this publication in new window or tab >>A simulation based study of low frequency transient sound radiation from floors: a concrete vs. a hybrid floor
2017 (English)In: Proceedings of the 24th International Congress on Sound and Vibration, Curran Associates, Inc., 2017Conference paper, Published paper (Other academic)
Abstract [en]

Timber is a renewable and human friendly construction material and thereby a potential solution toachieve life cycle sustainable buildings. However, it is clear that impact sound and vibrations withinthe low frequency range still are challenges for wooden joist floors. Another challenge is the,mostly, larger building heights of wooden or hybrid floors compared to the heights of concretefloors. Using timber as the structural joist floor material could imply fewer stories due to maximumallowed building heights, which renders in less income in a building project. Accurate simulationsof impact sound may decrease the need for prototypes; thus saving money and time in the timberbuilding industry. Here, a hybrid joist floor consisting of wood, sand and steel is compared to aconcrete floor in terms of radiated impact sound into a rectangular cavity. The hybrid floor is designedsuch that its mass distribution and global stiffness are close to the same properties of theconcrete floor. Finite element models are used for simulations of the radiated transient sound inducedby impact forces having the characteristics of human walking. The simulations indicate thatsimilar surface mass and bending stiffness of a floor intersection give similar impact sound transmissionproperties around the first bending mode, while it is not necessary so at higher frequencies.Keywords: timber buildings, impact sound, simulation

Place, publisher, year, edition, pages
Curran Associates, Inc., 2017
Keywords
timber buildings, impact sound, simulation
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-67181 (URN)
Conference
The 24th International Congress on Sound and Vibration (ICSV), London, 23-27 July, 2017
Available from: 2017-08-07 Created: 2017-08-07 Last updated: 2017-09-07Bibliographically approved
Kodakadath Premachandran, R., Linderholt, A., Håkansson, L. & Gothberg, M. (2017). An initial investigation of the correlation between a number of drilling related quantities measured during down the hole drilling. In: Proceedings of the 24th International Congress on Sound and Vibration: . Paper presented at The 24th International Congress on Sound and Vibration (ICSV), London. 23-27 July, 2017. Curran Associates, Inc.
Open this publication in new window or tab >>An initial investigation of the correlation between a number of drilling related quantities measured during down the hole drilling
2017 (English)In: Proceedings of the 24th International Congress on Sound and Vibration, Curran Associates, Inc., 2017Conference paper, Published paper (Other academic)
Abstract [en]

Optimizing the performance for down the hole (DTH) drills is becoming increasingly important. This is due to that the industry is becoming highly competitive and therefore there is an ever-increasing demand for improving the efficiency of the drilling process. To do this, it is important to have a robust monitoring system in place that should be based on in-depth knowledge of the underlying physics of the drilling system and process. Such a system will assist drillers in improving the perfor-mance e.g. by providing recommendations concerning the settings of the drilling. To understand the performance of the system, it is very important to understand the information that can be extracted from different drilling related quantities. In this work, information obtained from the pressure signals from the feed/holdback line, impact pressure line and rotation line together with vibration signals measured with the aid of accelerometers mounted at specific locations on the drill rig are discussed. For instance, spectral properties of these quantities for good and bad drilling cases are investigated. The results indicate correlations, to some extent, between the spectral properties and the quality of the drilling.

Place, publisher, year, edition, pages
Curran Associates, Inc., 2017
Keywords
DTH, Performance monitoring
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-67182 (URN)
Conference
The 24th International Congress on Sound and Vibration (ICSV), London. 23-27 July, 2017
Available from: 2017-08-07 Created: 2017-08-07 Last updated: 2018-05-17Bibliographically approved
Chen, Y., Linderholt, A. & Abrahamsson, T. (2017). Experimental Validation of a Nonlinear Model Calibration Method Based on Multiharmonic Frequency Responses. Journal of Computational and Nonlinear Dynamics, 12(4), Article ID 041014.
Open this publication in new window or tab >>Experimental Validation of a Nonlinear Model Calibration Method Based on Multiharmonic Frequency Responses
2017 (English)In: Journal of Computational and Nonlinear Dynamics, ISSN 1555-1415, E-ISSN 1555-1423, Vol. 12, no 4, article id 041014Article in journal (Refereed) Published
Abstract [en]

Correlation and calibration using test data are natural ingredients in the process of validating computational models. Model calibration for the important subclass of nonlinear systems which consists of structures dominated by linear behavior with the presence of local nonlinear effects is studied in this work. The experimental validation of a nonlinear model calibration method is conducted using a replica of the École Centrale de Lyon (ECL) nonlinear benchmark test setup. The calibration method is based on the selection of uncertain model parameters and the data that form the calibration metric together with an efficient optimization routine. The parameterization is chosen so that the expected covariances of the parameter estimates are made small. To obtain informative data, the excitation force is designed to be multisinusoidal and the resulting steady-state multiharmonic frequency response data are measured. To shorten the optimization time, plausible starting seed candidates are selected using the Latin hypercube sampling method. The candidate parameter set giving the smallest deviation to the test data is used as a starting point for an iterative search for a calibration solution. The model calibration is conducted by minimizing the deviations between the measured steady-state multiharmonic frequency response data and the analytical counterparts that are calculated using the multiharmonic balance method. The resulting calibrated model's output corresponds well with the measured responses.

Place, publisher, year, edition, pages
ASME Press, 2017
Keywords
nonlinear model calibration, multiharmonic frequency response, identifiability analysis, Fisher information matrix
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-60552 (URN)10.1115/1.4035670 (DOI)000401803900015 ()
Funder
VINNOVA, NFFP5
Available from: 2017-02-07 Created: 2017-02-07 Last updated: 2017-07-19Bibliographically approved
Chen, Y., Linderholt, A., Abrahamsson, T., Xia, Y. & Friswell, M. I. (2016). A Pretest Planning Method for Model Calibration for Nonlinear Systems. In: Model Validation and Uncertainty Quantification, Volume 3: Proceedings of the 34th IMAC, A Conference and Exposition on Structural Dynamics 2016. Paper presented at The 34th IMAC, Conference and Exposition on Structural Dynamics 2016 (pp. 371-379). Springer, 3
Open this publication in new window or tab >>A Pretest Planning Method for Model Calibration for Nonlinear Systems
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2016 (English)In: Model Validation and Uncertainty Quantification, Volume 3: Proceedings of the 34th IMAC, A Conference and Exposition on Structural Dynamics 2016, Springer, 2016, Vol. 3, p. 371-379Conference paper, Published paper (Other academic)
Abstract [en]

With increasing demands on more flexible and lighter engineering structures, it has been more common to take nonlinearity into account. Model calibration is an important procedure for nonlinear analysis in structural dynamics with many industrial applications. Pretest planning plays a key role in the previously proposed calibration method for nonlinear systems, which is based on multi-harmonic excitation and an effective optimization routine. This paper aims to improve the pretest planning strategy for the proposed calibration method. In this study, the Fisher information matrix (FIM), which is calculated from the gradients with respect to the chosen parameters with unknown values, is used for determining the locations, frequency range, and the amplitudes of the excitations as well as the sensor placements. This pretest planning based model calibration method is validated by a structure with clearance nonlinearity. Synthetic test data is used to simulate the test procedure. Model calibration and K-fold cross validation are conducted for the optimum configurations selected from the pretest planning as well as three other configurations. The calibration and cross validation results show that a more accurate estimation of parameters can be obtained by using test data from the optimum configuration.

Place, publisher, year, edition, pages
Springer, 2016
Series
Conference Proceedings of the Society for Experimental Mechanics Series, ISSN 2191-5644
Keywords
Nonlinear model calibration, pretest planning, clearance, multi-harmonic excitation, Fisher information matrix
National Category
Other Mechanical Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-51449 (URN)10.1007/978-3-319-29754-5_36 (DOI)000389798700036 ()2-s2.0-84978701119 (Scopus ID)978-3-319-29753-8 (ISBN)978-3-319-29754-5 (ISBN)
Conference
The 34th IMAC, Conference and Exposition on Structural Dynamics 2016
Available from: 2016-03-28 Created: 2016-03-28 Last updated: 2017-01-10Bibliographically approved
Gustafsson, P. & Linderholt, A. (2016). A Study of the Accuracy of Ground Vibration Test Data Using a Replica of the GARTEUR SM-AG19 Testbed Structure. In: The International Council of the Aeronautical Sciences (Ed.), Proceedings of the 30th Congress of the International Council of the Aeronautical Sciences: . Paper presented at The 30th Congress of the International Council of the Aeronautical Sciences, September 25-30, 2016, Daejeon, Korea. International Council of the Aeoronautical Sciences
Open this publication in new window or tab >>A Study of the Accuracy of Ground Vibration Test Data Using a Replica of the GARTEUR SM-AG19 Testbed Structure
2016 (English)In: Proceedings of the 30th Congress of the International Council of the Aeronautical Sciences / [ed] The International Council of the Aeronautical Sciences, International Council of the Aeoronautical Sciences , 2016Conference paper, Published paper (Other academic)
Abstract [en]

Ground Vibration Tests have been performed on a replica of the Group for Aeronautical Research and Technology in Europe (GARTEUR) testbed structure SM-AG19. The aim of the Ground Vibration Tests was to study the impact on modal data stemming from the test data, from the boundary conditions used to mimic a free-free condition. For the tests an air-spring support system was designed with the aim to give a behaviour that is in resemblance with the behaviour of real aircraft test conditions.

To eliminate a potential, unwanted, impact on the test results generated by the wing to fuselage interface as it was designed for the original structure (SM-AG19), a deviation from the original interface has been made on the structure for this particular study.

Place, publisher, year, edition, pages
International Council of the Aeoronautical Sciences, 2016
Keywords
GVT, vibrational test, suspension, air-spring, damping, eigenmodes, structural dynamics
National Category
Aerospace Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-56978 (URN)978-3-932182-85-3 (ISBN)
Conference
The 30th Congress of the International Council of the Aeronautical Sciences, September 25-30, 2016, Daejeon, Korea
Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-04-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4404-5708

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