The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Alf Warnock - One of the best experts on this subject based on the ideXlab platform.
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Heavy and light impact sources to rate impact sound transmission and changes due to applied floor toppings
The Journal of the Acoustical Society of America, 2006Co-Authors: Alf Warnock, Trevor R.t. NightingaleAbstract:The magnitude and spectrum of the power injected by an impact source depends on the impedance of the source and floor. If standardized impact tests are meant to give ratings that correlate well with subjective impressions of footstep noise, it follows that the impact source used should have the same impedance as an average human foot at least over the range of test frequencies. The ISO Tapping Machine, the Japanese tire Machine, and an 18‐cm‐diam rubber ball do not satisfy this criterion. Consequently, their impact spectra differ from those from a live walker. Floor toppings, in particular, are ranked differently. Examples of discrepancies will be presented for direct transmission between vertically separated rooms. For horizontally and diagonally separated rooms, flanking transmission controls the impact sound pressure level. The sound pressure level depends not only on the power injected by the source, but also source location relative to the flanking junction because of propagation attenuation across the floor. Sensitivity to source location is similar for different sources (ISO Tapping Machine and Japanese ball), suggesting that the same source could be used for direct and flanking transmission measurements if the source adequately simulates the impedance of a human foot.
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Low‐frequency impact sound rating of floor systems
The Journal of the Acoustical Society of America, 2000Co-Authors: Alf WarnockAbstract:An extensive series of measurements of airborne and impact sound insulation on joist floors of various types was recently completed at NRC. About 190 floors with different joist types, subfloors, ceiling types, ceiling support systems, and type and thickness of sound absorber were constructed and sound insulation measured to frequencies lower than required by standards. The joist types comprised solid wood, wood trusses, I‐joists, and steel joists. Glass, rock, and cellulose fiber sound‐absorbing material were used. Three concrete slabs were included in the series and a few of the joist floors had concrete toppings installed. Impact devices used on the floors included the standard ISO/ASTM E492 Tapping Machine, a walker, a JIS 1419 tire impactor, and two experimental rubber balls. The impact measurements provide an extensive, consistent set for examining alternative impact tests and possible modifications to standard tests using the ISO Tapping Machine. Correlations among the sound levels from the different impactors show that levels from the ISO Tapping Machine correlate well with those from a walker at low frequencies, although the spectra are quite different in shape. An overview of the data and the prospects for a new test method and rating system will be presented.
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Low‐frequency impact sound transmission through floor systems
The Journal of the Acoustical Society of America, 1999Co-Authors: Alf WarnockAbstract:An extensive series of measurements of airborne and impact sound insulation on joist floors of various types was recently completed at NRC. About 190 floors with different joist types, subfloors, ceiling types, ceiling support systems, and type and thickness of sound absorber were constructed and sound insulation measured to frequencies lower than required by standards. The joist types comprised solid wood, wood trusses, I‐joists, and steel joists. Glass, rock, and cellulose fiber sound‐absorbing materials were used. Three concrete slabs were included in the series and a few of the joist floors had concrete toppings installed. Impact devices used on the floors included the standard ISO/ASTM E492 Tapping Machine, a walker, a JIS 1419 tire impactor, and two experimental rubber balls. The impact measurements provide an extensive, consistent set for examining alternative impact tests and possible modifications to standard tests using the ISO Tapping Machine. Correlations among the sound levels from the different impactors show that levels from the ISO Tapping Machine correlate well with those from a walker at low frequencies although the spectra are quite different in shape. The data and the prospects for a new test method and rating system will be discussed.
Ulrik Sundbäck - One of the best experts on this subject based on the ideXlab platform.
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An investigation of the characteristics of impact sound sources for impact sound insulation measurement
Applied Acoustics, 1997Co-Authors: Wanqing Shi, Carin Johansson, Ulrik SundbäckAbstract:At the assessment of the impact sound insulation of a construction, a standard Tapping Machine is used as sound source. However, the current standard Tapping Machine has been criticised especially for measurement of wooden joist floors since the sounds generated by a Tapping Machine differ from those generated by actual footfall. This study has investigated the waveform and frequency spectra of human footfall (walking, running and jumping), of sand balls, sand bags and dropped tires, and of the standard Tapping Machine. It is shown that the frequency spectra differ between the standard Tapping Machine and actual footfall, especially at low frequencies. Results from other excitation sources such as a sand ball falling from a certain height showed concordance with actual footfall. This means that a sand ball drop as an impact source provides a better representation of actual human footfall than the standard Tapping Machine.
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Assessment of the sound insulation of a wood joist construction due to different types of impact sources
Applied Acoustics, 1996Co-Authors: Shi Wanqing, Carin Johansson, Ulrik SundbäckAbstract:The ISO standard Tapping Machine was specified as an impact source to assess the sound insulation of floors. The problem is that the noise spectrum produced by the Tapping Machine does not give sim ...
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Comparison of the characteristics of the different impact force with standard Tapping Machine
1995Co-Authors: Wanqing Shi, Carin Johansson, Ulrik SundbäckAbstract:Comparison of the characteristics of the different impact force with standard Tapping Machine
Krister Larsson - One of the best experts on this subject based on the ideXlab platform.
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Influence of Tapping Machine position on timber joist floors on the low frequency impact sound
2012Co-Authors: Krister Larsson, Nata Amiryarahmadi, Christian Simmons, Xuetao ZhangAbstract:Influence of Tapping Machine position on timber joist floors on the low frequency impact sound
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Time-domain model of a Tapping Machine
2011Co-Authors: Nata Amiryarahmadi, Wolfgang Kropp, Delhpin, Krister LarssonAbstract:In the past few years the use of lightweight buildings made of prefabricated wooden elements has become more common. Ease of installation, high accuracy and lightness of such buildings has attracted builders and designers. Sweden, having a large coverage of renewable forests has an increasing interest in multi-storey wooden buildings. However noise and vibration in wooden buildings is an issue of concern especially low frequency impact sound due to footsteps. Impact sound insulation of floors can be measured based on ISO 140-7 using standardized Tapping Machine as excitation source. Experience has shown that in many cases the results obtained by this method do not correlate with annoyance experienced by inhabitants. On the other hand, the method presented in ISO 140-7 has usually shown to be relevant for the evaluation of impact sound transmission of concrete floors. Discovering the source of this contradiction requires deeper understanding of the impact process. A first step would be to find the difference between contact forces of the Tapping Machine on different floor materials. One could then correlate it with inhabitants’ perceived annoyance. This paper is the first step of this investigation which is a part of a Swedish research project called AkuLite. In this work a time-dependent model based on Hertz’s contact law is presented for the Tapping Machine. The model is validated by measurements on a homogeneous concrete floor. Also the contribution of parameters such as damping and stiffness of floor material on the resulting impact force and vibrations is studied.
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Measurements of structure-borne sound from building service equipment by a substitution method - Round robin comparisons
Noise Control Engineering Journal, 2011Co-Authors: Krister Larsson, Christian SimmonsAbstract:A pilot project has been performed with a round robin comparison (inter-laboratory test), where a modified heavy-duty washing Machine has been circulated for tests among 6 laboratories. The main goal of this pilot project was to find out whether a simple substitution method could be applied to estimate the structure-borne sound pressure level of some typical building service equipments. First, the vibration levels of a heavy low mobility test floor are measured when a Machine with high internal mobility operates on this floor. Then, the vibration levels are measured at the same positions on the same floor when a standardized Tapping Machine (ISO 140-7) operates in the same positions as the test Machine. The differences between the vibration level are then calculated. The difference may be used to compare the performance of different Machines at one site or to estimate the sound pressure level in other buildings with heavy floors. In its simplest form, this can be made in the same way as for floorings, i.e., first calculating the normalized impact sound pressure level (EN 12354-2) and then subtracting the vibration level difference of the actual Machine compared to the Tapping Machine. It remains to apply this method in the field and to compare estimated sound pressure levels with measured.
Yang Ming-liang - One of the best experts on this subject based on the ideXlab platform.
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Design of Compound Vibration Cold-extruding Tapping Machine
Hot Working Technology, 2011Co-Authors: Yang Ming-liangAbstract:The working principle and main features of compound vibration cold-extruding Tapping Machine and the structure and components of the control system were described.CNC technology was applied in the new type of Tapping Machine with the function of rotational vibration and axial vibration.The function of universal Tapping leading mould was realized,which could met the demands of the new technique in vibration extruding Tapping.
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Measurement of Vibration Parameters of Vibration Tapping Machine Based on Virtual Instrument
Journal of Mechanical Engineering, 2011Co-Authors: Yang Ming-liangAbstract:For the mechanical vibration Tapping Machine,it is hard to measure vibration parameter when spindle has rotary vibration as well as rotary motion and axial movement.The major difficulty is to pick up the vibration signals.The torsion vibration signals with changed amplitude and unchanged frequency are obtained by the sine derivative modulation of the constant amplitude.After the modulation,the torsional vibration signals contain the information of vibration frequency and amplitude.By using the virtual instrument technology,vibration frequency and amplitude can be obtained from the modulated signals.Because the measuring range of the displacement sensor is larger than the range of torsional vibration amplitude,a high accuracy of A/D converter is required.The instrument can realize online real-time calibration.By combining the signal modulation technology with the virtual instrument technology,the vibration parameter measurement problem of the vibration Tapping Machine is solved.This measurement principle is proved feasible by experiments.
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The research on cold-extruding Tapping process and equipment of compound vibration in difficult for Machine materials
Modern Manufacturing Engineering, 2011Co-Authors: Yang Ming-liangAbstract:Gave the difficulty of Tapping and the feasibility of extrusion Tapping instead of cutting on titanium,according to the performance of titanium.And developed extrusion Tapping Machine with composite vibration for difficult materials adapted to the Tapping a small screw on this basis.CNC technology is a Tapping applied,in the new type of Tapping Machine with function of rotational vibration and axial vibration,function of general Tapping leading model is realized,which has met the demands of the new technique in vibration extruding Tapping.
Jiho Lee - One of the best experts on this subject based on the ideXlab platform.
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The responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact sound: a pilot study
Annals of Occupational and Environmental Medicine, 2017Co-Authors: Seok Hyeon Yun, Sang Jin Park, Chang Sun Sim, Joo Hyun Sung, Ahra Kim, Jang Myeong Lee, Sang Hyun Lee, Jiho LeeAbstract:Background Recently, noise coming from the neighborhood via floor wall has become a great social problem. The noise between the floors can be a cause of physical and psychological problems, and the different types of floor impact sound (FIS) may have the different effects on the human’s body and mind. The purpose of this study is to assess the responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact. Methods Ten men and 5 women were enrolled in our study, and the English listening test was performed under the twelve different types of FIS, which were made by the combinations of bang Machine (B), Tapping Machine (T), impact ball (I) and sound-proof mattress (M). The 15 subjects were exposed to each FIS for about 3 min, and the subjective annoyance, performance ability (English listening test), cortisol level of urine/saliva and heart rate variability (HRV) were examined. The sound pressure level (SPL) and frequency of FIS were analyzed. Repeated-measures ANOVA, paired t-test, Wilcoxon signed rank test were performed for data analysis. Results The SPL of Tapping Machine (T) was reduced with the soundproof mattress (M) by 3.9–7.3 dBA. Impact ball (I) was higher than other FIS in low frequency (31.5–125 Hz) by 10 dBA, and Tapping Machine (T) was higher than other FIS in high frequency (2–4 k Hz) by 10 dBA. The subjective annoyance is highest in the combination of bang Machine and Tapping Machine (BT), and next in the Tapping Machine (T). The English listening score was also lowest in the BT, and next in T. The difference of salivary cortisol levels between various types of FIS was significant ( p = 0.003). The change of HRV parameters by the change of FIS types was significant in some parameters, which were total power (TP) ( p = 0.004), low frequency (LF) ( p = 0.002) and high frequency (HF) ( p = 0.011). Conclusions These results suggest that the human’s subjective and objective responses were different according to FIS types and those combinations.
