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Olsson, J. & Linderholt, A. (2019). Force to sound pressure frequency response measurements using a modified tapping machine on timber floor structures. Engineering structures, 196, Article ID 109343.
Open this publication in new window or tab >>Force to sound pressure frequency response measurements using a modified tapping machine on timber floor structures
2019 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 196, article id 109343Article in journal (Refereed) Published
Abstract [en]

In recent years, research has shown that the lower frequency portion of impact sound, down to 20 Hz, is of significant importance to residents' perception in buildings that have lightweight timber floors. At low frequencies, the finite element method is a useful tool for predictive analysis. Impact sound frequency response functions, which are easily calculated using finite element software, are useful as they offer a common ground for studies of correlations between measurements and analyzes. On the measurement side, the tapping machine is well defined and has become the standard excitation device for building acoustics. When using a tapping machine, the excitation force spectrum generated - necessary to achieving experimental frequency force to sound response functions - is unknown. Different equipment may be used for excitation and force measurements and if a structure behaves linearly, the use of any excitation devices should result in the same frequency response functions. Here, an ISO tapping machine hammer is fitted with an accelerometer, enabling estimates of input force spectra. In combination with measurements of the sound in the receiver room, frequency response functions are then achieved using an ISO tapping machine. Various excitation devices have been used on a floor partition in a timber building and on a cross-laminated timber (CLT) lab. floor in order to compare the resulting frequency response functions. Structural nonlinearities are evident, implying that for accurate frequency response measurements in acoustically low frequencies, excitation magnitudes and characteristics that are similar to these which stem from human excitations, should preferably be used.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Low-frequency, Impact sound, Frequency response functions, Measurements, vibrations, Timber buildings
National Category
Mechanical Engineering
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-89254 (URN)10.1016/j.engstruct.2019.109343 (DOI)000482518700069 ()
Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Roettgen, D. & Linderholt, A. (2019). Planning of a Black-box Benchmark Structure for Dynamic Substructuring. In: The International Modal Analysis Conference; IMAC XXXVII: . Paper presented at The International Modal Analysis Conference; IMAC XXXVII, January 28-31, 2019, Orlando, Florida.
Open this publication in new window or tab >>Planning of a Black-box Benchmark Structure for Dynamic Substructuring
2019 (English)In: The International Modal Analysis Conference; IMAC XXXVII, 2019Conference paper, Published paper (Other academic)
Abstract [en]

Experimental Analytical substructuring has been a popular field of research for several years and has seen many great advances for both frequency based substructuring (FBS) and component mode synthesis (CMS) techniques. To examine these technical advances, a new benchmark structure is being designed through the SEM Dynamic Substructuring technical division to act as a black-box study for anyone researching in the field. This black-box challenge will include experimental subcomponents and a finite element model to which these experimental results are to be connected. We often know the truth target when completing substructuring research; however, this challenge allows researchers to test their techniques without the aid of a truth measurement. IMAC XXXVII attendees are encouraged to contact the authors in order to join the team designing the black-box hardware and/or eventually have their institution participate in this challenge. The results from the assembled truth measurement will be presented at IMAC XXXIX.

National Category
Applied Mechanics
Identifiers
urn:nbn:se:lnu:diva-80177 (URN)
Conference
The International Modal Analysis Conference; IMAC XXXVII, January 28-31, 2019, Orlando, Florida
Available from: 2019-02-03 Created: 2019-02-03 Last updated: 2019-08-28
Landel, P., Linderholt, A. & Johansson, M. (2019). Test-analyses comparisons of a stabilizing glulam truss for a tall building. In: Book of abstracts: CompWood June 17-19, 2019, Växjö, Sweden: International Conference on Computational Methods in Wood Machanics - from Material Properties to Timber Structure. Paper presented at CompWood 2019, June 17-19, Växjö. Linnaeus University
Open this publication in new window or tab >>Test-analyses comparisons of a stabilizing glulam truss for a tall building
2019 (English)In: Book of abstracts: CompWood June 17-19, 2019, Växjö, Sweden: International Conference on Computational Methods in Wood Machanics - from Material Properties to Timber Structure, Linnaeus University , 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Linnaeus University, 2019
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-85543 (URN)978-91-88898-64-7 (ISBN)
Conference
CompWood 2019, June 17-19, Växjö
Funder
Swedish Research Council Formas, 942-2015-115
Available from: 2019-06-18 Created: 2019-06-18 Last updated: 2019-08-27Bibliographically approved
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)2-s2.0-85058173513 (Scopus ID)
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: 2019-05-27Bibliographically 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.

Place, publisher, year, edition, pages
Institute of Noise Control Engineering, 2018
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 ()2-s2.0-85052959047 (Scopus ID)
Available from: 2018-09-20 Created: 2018-09-20 Last updated: 2019-08-29Bibliographically 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)2-s2.0-85058680787 (Scopus ID)9781510868458 (ISBN)
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: 2019-05-27Bibliographically 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: 25th International Congress on Sound and Vibration 2018 (ICSV 25): Hiroshima Calling. Proceedings of a meeting held 8-12 July 2018, Hiroshima, Japan. Paper presented at 25th International Congress on Sound and Vibration 2018 (ICSV 25) (pp. 394-401). Auburn, AL: International Institute of Acoustics & Vibration, 1
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: 25th International Congress on Sound and Vibration 2018 (ICSV 25): Hiroshima Calling. Proceedings of a meeting held 8-12 July 2018, Hiroshima, Japan, Auburn, AL: International Institute of Acoustics & Vibration , 2018, Vol. 1, p. 394-401Conference 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
Auburn, AL: International Institute of Acoustics & Vibration, 2018
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-73954 (URN)2-s2.0-85058711131 (Scopus ID)9781510868458 (ISBN)
Conference
25th International Congress on Sound and Vibration 2018 (ICSV 25)
Available from: 2018-05-05 Created: 2018-05-05 Last updated: 2019-05-24Bibliographically 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)2-s2.0-85029438254 (Scopus ID)
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: 2019-05-28Bibliographically 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)2-s2.0-85029422414 (Scopus ID)
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: 2019-06-11Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4404-5708

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