| 1. |
- Bard, Delphine, et al.
(författare)
-
Measurements of vibration in wooden floor induced by walking
- 2009. - PART 3
-
Ingår i: 8th European Conference on Noise Control 2009, EURONOISE 2009. - 9781615676804 ; 31
-
Konferensbidrag (refereegranskat)abstract
- Timber floors receive a lot of attention nowadays because of their advantages, such as cost effectiveness, recyclability. On the other hand, more and more complains arise again this type of structures, related to the propagation of low frequency vibrations induced by human activities. Most problems are caused by human walking, more exactly foot impacts, which generate a harmonic force whose frequency is close to the natural frequency of the floor. The present investigation is focused on measurements and subjective tests; those were performed on an experimental wooden floor. The floor structure dimensions are 4.8 m by 2.4 m. The average spacing between the beams is 0.53 m and the height of the 6 supports is 4.5 cm. The subjective tests were performed according to Talja & Toratti's method. The measurements of accelerations induced by a walking person and the results from the subjective tests were then used to evaluate existing vibration criteria.
|
|
| 2. |
- Deckers, E., et al.
(författare)
-
A novel wave based prediction technique for the efficient dynamic modelling of poro-elastic materials
- 2009
-
Ingår i: 8th European Conference on Noise Control 2009, EURONOISE 2009 - Proceedings of the Institute of Acoustics. - 9781615676804
-
Konferensbidrag (refereegranskat)abstract
- The most commonly used prediction techniques to study the behaviour of poro-elastic materials are based on the finite element method (FEM). In the case of poro-elastic materials, certain material properties are frequency dependent. This implies that the system matrices have to be recalculated for each frequency, which is time consuming and disadvantageous for the method. As frequency increases, the model size increases drastically, such that these methods are restricted to low-frequency calculations. This paper presents a novel wave based prediction technique to solve the poro-elastic Biot wave equations in an efficient manner. wave functions that exactly satisfy the governing differential equations are used as an expansion set to describe the field variables. This leads to small model sizes and allows the method to be applied also at higher frequencies. The paper describes the basic concepts of the method and illustrates its potential through some dedicated two-dimensional validation calculations.
|
|
| 3. |
- Forssén, Jens, 1968, et al.
(författare)
-
Road traffic noise propagation to an inner yard – Measurements before and after the construction of gap filling buildings
- 2009
-
Ingår i: 8th European Conference on Noise Control 2009, EURONOISE 2009; Edinburgh; United Kingdom; 26 October 2009 through 28 October 2009. - 9781615676804 ; :PART 3, s. 7-
-
Konferensbidrag (refereegranskat)abstract
- The propagation of noise to inner yards is a subject of large interest, for instance due to new formulations of noise limits. The presented measurements were made within a larger research programme, in one of its application examples, for which also a perceptual study is ongoing. Here, the propagation of noise from the motorway nearby is investigated using acoustic measurements from both before and after gap filling buildings were constructed. As result of the construction, gaps between a row of housing buildings were sealed by additional housing units thus forming a continuous, tall and thick barrier along the motorway. It is shown that the row of separate buildings with gaps in-between, in the before-study, provided minor shielding of the yard behind, whereas, in the after-study, significantly lower noise levels were found. The reduction due to the gap filling buildings is estimated to reach 8-9 dB at most.
|
|
| 4. |
- Hellström, Björn, 1959-, et al.
(författare)
-
Room acoustic design in open-plan offices
- 2009
-
Ingår i: Proceedings of the Institute of Acoustics Volume 31 Pt.3. - St. Albans, United Kingdom : Institute of Acoustics. - 9781615676804 ; , s. 2954-2959
-
Konferensbidrag (refereegranskat)abstract
- In a Nordic cooperation project the acoustical conditions in open-plan offices was investigated. Measurements have been carried out in five open plan offices accompanied with an inquiry gathering the subjective judgments by the staff. A program for the acoustical measurements was designed specifying how to perform the measurements and which type of parameters to measure. The acoustical parameters included in the measurements are Reverberation time T20, Early Decay Time (EDT), Clarity (C50), Speech transmission index (STI), Speech intelligibility index (SII), Privacy Index (PI), Rate of spatial decay of sound pressure levels per distance doubling (DL2 ), Excess of sound pressure level with respect to a reference curve (DLf), background noise levels in occupied and unoccupied offices. In two of the offices are furbishment program was carried out. Measurements as well as questionnaire were accomplished after refurbishment. The effect on room acoustic parameters DL2 and DLf and on subjective judgments by the staff will be presented in this paper.
|
|
| 5. |
- Janssen, Sabine A., et al.
(författare)
-
Exposure-response relationships for annoyance by wind turbine noise : a comparison with other stationary sources
- 2009
-
Ingår i: 8th European Conference on Noise Control 2009 (EURONOISE 2009). - St. Albans Hertfordshire, UK : Institute of Acoustics. - 9781615676804 ; , s. 1472-1478
-
Konferensbidrag (refereegranskat)abstract
- There are indications that, given a certain level of noise exposure, the expected annoyance by wind turbine noise is higher than that by noise from other sources such as industrial noise or transportation noise. The aim of the present study was to establish the exposure-response relationship between wind turbine noise exposure and the expected percentage annoyed residents on the basis of available data. Data from two surveys in Sweden (N=341, N=754) and one survey in the Netherlands (N=725) were combined to achieve relationships between Lden and annoyance indoors as well as annoyance outdoors at the dwelling. In addition, the influence of several individual and situational factors was assessed. In particular, annoyance was lower in residents who received economical benefit from wind turbines, and higher in residents for whom the wind turbine was visible from the dwelling. Age and noise sensitivity had similar effects on annoyance to those found in research on annoyance by other sources. The exposure-response relationship for wind turbine noise is compared to previously established relationships for industrial noise.
|
|
| 6. |
- Jerson, T, et al.
(författare)
-
How does noise annoyance relate to traffic intensity?
- 2010
-
Ingår i: Proceedings of the 10th International Workshop on Railway Noise, 18-22 October 2010, Nagahama, Japan. - : Curran Associates, Inc.. - 9781615676804 ; , s. 1-7
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study is part of the Swedish research program TVANE, where a number of questionnaire surveys has been performed. A comparison between three areas demonstrate that the reported annoyance is higher where the traffic intensity is higher even if the equivalent noise level is the same. The traffic intensity varies with a factor of 7 between the areas, and the reported annoyance is increased 1.3 –2.5 times.
|
|
| 7. |
- Ögren, Mikael, et al.
(författare)
-
Effects of railway noise and vibrations on sleep : experimental studies within the Swedish research program TVANE
- 2009
-
Ingår i: 8th European Conference on Noise Control 2009 (EURONOISE 2009). - : Curran Associates, Inc.. - 9781615676804 ; , s. 1214-1221
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes a laboratory sleep study with an exposure situation corresponding to a dwelling close to a railway. Both noise and bed vibrations were generated for passing trains, and the sleep quality of the test subjects was evaluated using questionnaires before and after sleep. A total of 21 test subjects slept five nights in the laboratory, and three different exposure situations were presented in a randomized order after two nights for habituation. The three exposures were combined from two noise levels and two vibration amplitudes; one with high noise levels and strong vibrations, one with lower noise levels and strong vibrations and one with high noise levels and weaker vibrations. The results indicate that the perceived sleep disturbance from noise increased with increasing vibration amplitude. There was no such interaction effect for perceived sleep disturbance due to vibrations, i.e. sleep disturbance due to vibrations was the same irrespective of noise level. These results suggest that it will not be sufficient to reduce the noise levels to protect from sleep disturbances, e.g. by sound insulating windows and noise barriers, if vibration levels are high. The vibration levels must also be addressed.
|
|
