Shibata Nobuyuki, Hosoya Naoki, Maeda Setsuo
Department of Research Planning and Coordination, National Institute of Occupational Safety and Health, Kawasaki, Japan.
Ind Health. 2008 Dec;46(6):629-34. doi: 10.2486/indhealth.46.629.
Prolonged exposure to hand-arm vibration (HAV) due to use of hand-held power tools leads to an increased occurrence of symptoms of disorders in the vascular, neurological, and osteo-articular systems of the upper limbs called hand-arm vibration syndrome (HAVS). Biodynamic responses of the hand-arm system to vibration can be suggestive parameters that give us better assessment of exposure to HAV and fundamental data for design of low-vibration-exposure power tools. Recently, a single axis hand-arm vibration system has been installed in the Japan National Institute of Occupational Safety and Health (NIOSH). The aims of this study were to obtain the fundamental dynamic characteristics of an instrumented handle and to validate the performance and measurement accuracy of the system applied to dynamic response measurement. A pseudo-random vibration signal with a frequency range of 5-1,250 Hz and a power spectrum density of 1.0 (m/s2)2/Hz was used in this study. First the dynamic response of the instrumented handle without any weight was measured. After this measurement, the dynamic response measurement of the handle with weights mounted on the handle was performed. The apparent mass of a weight itself was obtained by using the mass cancellation method. The mass of the measuring cap on the instrumented handle was well compensated by using the mass cancellation method. Based on the 10% error tolerance, this handle can reliably measure the dynamic response represented by an apparent mass with a minimum weight of 2.0 g in a frequency range of 10.0 to 1,000 Hz. A marked increase in the AM magnitude of the weights of 15 g and 20 g in frequency ranges greater than 800 Hz is attributed not to the fundamental resonance frequency of the handle with weights, but to the fixation of the weight to the measuring cap. In this aspect, the peak of the AM magnitude can be reduced and hence should not be an obstacle to the biodynamic response measurement of the human hand-arm system. On the basis of the results obtained in this study, we conclude that this hand-arm vibration test system can be used to measure biodynamic response parameters of the human hand-arm system.
由于使用手持式电动工具而长期暴露于手臂振动（HAV）会导致上肢血管、神经和骨关节系统出现疾病症状的几率增加，这种情况被称为手臂振动综合征（HAVS）。手臂系统对振动的生物动力学响应可以作为提示性参数，有助于我们更好地评估手臂振动暴露情况，并为低振动暴露电动工具的设计提供基础数据。最近，日本国家职业安全与健康研究所（NIOSH）安装了一个单轴手臂振动系统。本研究的目的是获取装有仪器的手柄的基本动态特性，并验证该系统用于动态响应测量的性能和测量精度。本研究使用了频率范围为5 - 1250 Hz、功率谱密度为1.0（m/s²）²/Hz的伪随机振动信号。首先测量了未加载任何重物的装有仪器的手柄的动态响应。在此测量之后，对手柄上安装了重物的情况进行动态响应测量。通过质量抵消法获得重物本身的表观质量。使用质量抵消法很好地补偿了装有仪器的手柄上测量帽的质量。基于10%的误差容限，该手柄能够在10.0至1000 Hz的频率范围内可靠地测量以表观质量表示的动态响应，最小重物质量为2.0 g。在频率大于800 Hz的范围内，15 g和20 g重物的AM幅值显著增加，这并非归因于装有重物的手柄的基本共振频率，而是由于重物与测量帽的固定。在这方面，AM幅值的峰值可以降低，因此不应成为人体手臂系统生物动力学响应测量的障碍。基于本研究获得的结果，我们得出结论，该手臂振动测试系统可用于测量人体手臂系统的生物动力学响应参数。
