Maeda S, Griffin M J
Department of Industrial Engineering, Faculty of Science and Technology, Kinki University, Osaka, Japan.
Cent Eur J Public Health. 1995;3 Suppl:57-61.
The effect of shock repetition rate on the temporary threshold shifts (TTSs) in vibrotactile perception at the fingers has been studied with shocks having exponential decays and hanning waveforms. The repetition rate of shocks delivered at the hand varied from 2 shocks per second up to 64 shocks per second. Subjects were exposed to vertical hand-transmitted repetitive shock vibration of equal energy contents. The magnitudes of the stimuli were adjusted to 2.8 ms-2 r.m.s. so that they were all equally severe according to current standards for assessing the severity of hand-transmitted vibration (e.g. International Standard 5349, 1986). It was found that the TTS in vibrotactile perception decreased with decreasing shock repetition rate for both waveforms. The relation between the TTS, the logarithm of exposure time, and the logarithm of the ratio between the frequency-weighted r.m.s. acceleration and the peak amplitude was described by the relation TTS = 16.1 + 3.9log10T + 17.9log10 (RMS/PEAK), where TTS is the temporary threshold shift (in decibels), T is the exposure time, and RMS is the frequency-weighted r.m.s. acceleration according to BS 6842 and ISO 5349, and PEAK is the peak amplitude of the frequency-weighted acceleration. This shows that current standards are not appropriate for the prediction of the changes in vibrotactile perception produced by shocks such as those on many hand-held percussive tools.
研究了冲击重复率对手指振动触觉感知中暂时阈移（TTS）的影响，所使用的冲击具有指数衰减和汉宁波形。施加于手部的冲击重复率从每秒2次变化到每秒64次。受试者暴露于能量含量相等的垂直手部传递的重复性冲击振动中。将刺激强度调整为2.8 ms-2均方根值，以便根据当前评估手部传递振动严重程度的标准（例如国际标准5349，1986），所有刺激的严重程度都相同。结果发现，对于两种波形，振动触觉感知中的TTS都随着冲击重复率的降低而减小。TTS、暴露时间的对数以及频率加权均方根加速度与峰值幅度之比的对数之间的关系由TTS = 16.1 + 3.9log10T + 17.9log10（RMS/PEAK）表示，其中TTS是暂时阈移（以分贝为单位），T是暴露时间，RMS是根据BS 6842和ISO 5349的频率加权均方根加速度，PEAK是频率加权加速度的峰值幅度。这表明当前标准不适用于预测由诸如许多手持式冲击工具上的冲击所产生的振动触觉感知变化。
