振動公害基準値に関する基礎的研究

II 振動解析と評価について

抄録

In this paper, the author reports his study of the measurement and the analysis methods of vibrations caused by the vehicular traffic, The paragraph of Vibration Level Meter with weighting circuits based on the standard of the Acoustical Society of Japan defining a similar frequency function as in the International Standard ISO-2631, has been already added to Japan Industrial Standard (JIS C-1510). In the case of the largely variable vibration level caused by the vehicular traffic, the typical level of the measurement point has been defined as the 10% upper level of readings obtained from 100 samples taken every 5 seconds by a Vibration Level Meter. But its measurement and analysis in regard to the vibration threshold problem are as yet doubtful for the lack of a probabilistic approarch to the evaluation of the data.
The author has discussed several problems of Vibration Level Meter and the basis of a probabilistic analysis method. The results obtained are as follows:
1. The difference of Vibration Level between “Fast” and “Slow” as a dynamic characteristic of the needle on Vibration Level Meter is 3∼4dB without considering the crest and level of vibrations.
2. Vibration Level and vibration velocity are relative in the frequency range above 8Hz, but are independent in the case when the frequency is below 8Hz.
3. The 10% upper level approximately agrees with the mean level of the maximum distribution of all variations as well as the mean plus the standard deviation of the peak distribution. This fact is useful in establishing a more exact evaluation method. But it is not always appropriate to use the 10% upper level obtained by reading one hundred Vibration Levels every 5 seconds because to do so leads to noticable errors (2∼3dB).