| 1. |
- Bard, Delphine, et al.
(author)
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Challenges for acoustic calculation models in "silent timber build", Part 1- FEM
- 2014
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In: INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering : Improving the World Through Noise Control - Improving the World Through Noise Control. - 9781634398091 - 9780909882037 ; , s. 4424-4429
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Conference paper (peer-reviewed)abstract
- The project "Silent Timber Build" will develop new prediction tools for timber structures. There are several challenges that have to be overcome to provide a full prediction tool. The differences in weight, stiffness and density for wooden structures compared to traditional, heavy and more homogeneous structural material have repercussions on how the sound propagates throughout the structures, affecting the sound and vibration insulation performance and also theories to be used in prediction models. Finite element simulations have proved to be useful in the design phase in a certain low and very low frequency range. By further developing reliable finite element tools for low frequencies, the performance of future wooden constructions can be predicted in a full frequency range, saving both time and money as all calculations, and modifications can be done during the design phase. However the upper limit for using FEM has to be further investigated and then be merged with statistical methods. This article, following another article Part 2, will focus on medium and high frequency range calculations. For full-scale building, Virtual SEA method, as analytic and SEA approaches will be used in frequencies low enough in order to optimize the overlap to FEM.
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| 2. |
- Hagberg, Klas, et al.
(author)
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Low frequency sound transmission in multifamily wooden houses
- 2014
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In: INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering : Improving the World Through Noise Control - Improving the World Through Noise Control. - 9780909882037 - 9781634398091 ; , s. 4455-4461
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Conference paper (peer-reviewed)abstract
- In the recently finished research projects, AkuLite and AcuWood, it is clearly stated that low frequencies should be considered far more, prior to design new wooden structural building system. Lower than 50 Hz is preferable, and the most annoying frequencies appear between 20 and 50 Hz. However, it is still a long way to go in order to convince acousticians, the entire global industry and authorities that these frequencies have to be considered in order to build wooden structures which are experienced by the habitants as equally good as heavy structures. To "save" the industry, a lower limit of at least 50 Hz at least for impact sound should be mandatory in the near future globally, in spite of the fact that the new standard ISO 16717 will not be reality. This paper describes the main reasons why it is needed to include these low frequencies in residential buildings. It describes different constructions and their appearance due to low frequency impact sound transmission. The paper comprises some examples designed to fulfill the Swedish requirements, which equals Ln,Tw and Ln,Tw+CI,50-2500 ≤ 56 dB between dwellings. It comprises also a discussion regarding optimizing constructions for various uses, e.g. different types of housing.
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| 3. |
- Kouyoumji, Jean Luc, et al.
(author)
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Challenges for acoustic calculation models in "Silent Timber Build", Part 2
- 2014
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In: 43rd International Congress on Noise Control Engineering (INTERNOISE 2014) : Improving the World Through Noise Control - Improving the World Through Noise Control. - 9781634398091 - 9780909882037 ; , s. 3054-3061
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Conference paper (peer-reviewed)abstract
- The project "Silent Timber Build" will develop new prediction tools for timber structures. There are several challenges that have to be overcome to provide a full prediction tool. The differences in weight, stiffness and density for wooden structures compared to traditional, heavy and more homogeneous structural material have repercussions on how the sound propagates throughout the structures, affecting the sound and vibration insulation performance and also theories to be used in prediction models. The project will use Finite element simulations (FEM) and Statistical Energy Analysis (SEA) approaches to predict acoustical behavior of light weight timber constructions. This article, following another article Part 1, will focus on medium and high frequency range calculations. Statistical methods will be used in the medium and high frequency, where the acoustic performance of wooden building components (walls and floors) is generally limited by the presence of structural links and couplings. Statistical Energy Analysis (SEA) has proven to be an efficient approach, providing robust vibroacoustic models in this frequency region. The extension of statistical methods towards the low frequencies has to be evaluated, especially regarding time responses of impact noise on floor systems. For full-scale building, Virtual SEA method will be used as well as analytic SEA approach in frequencies low enough in order to optimize the overlap to FEM.
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| 4. |
- S.youssef, Rabab, et al.
(author)
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Acoustical quality assessment of lecture halls at Lund University, Sweden
- 2014
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In: 43rd International Congress and Exposition on Noise Control Engineering (Internoise 2014) : Improving the World Through Noise Control - Improving the World Through Noise Control. - 9781634398091 - 9780909882037 ; , s. 1382-1391
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Conference paper (peer-reviewed)abstract
- Noise control in buildings should aim at reducing disturbances caused by speech noise (i.e., improve speech privacy, speech intelligibility). Room acoustics can be controlled with high room absorption, high screens and bookcases, and sufficient masking sound. This research concerns as important aspect of room acoustic metrology, the ability to quantify the most relevant room acoustic parameters for academic purposes. In this proposed study we will focus on the lecturing rooms of Lund University, of which some have designed quite recently while others were constructed many years ago. As the use of audio- visual equipment as well as the use of enabling techniques for disabled students is continuingly increasing. Lecture halls, which have not been explicitly designed for the use of such equipment, are being fitted with an assortment of audio-visual fixtures. This can lead to far less environment profoundly impacts the outcome of the learning process it is performance to assess the current state of the situation with respect to the acoustic performance of lecture halls at Lund University.
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