Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, SO17 1BJ, UK.
Ind Health. 2010;48(5):538-49. doi: 10.2486/indhealth.mswbvi-05.
Fore-and-aft vibration of a backrest can influence discomfort and the risk of injury associated with whole-body vibration. Relevant standards (BS 6841:1987 and ISO2631-1:1997) recommend the W(c) frequency weighting for evaluating fore-and-aft vibration of backrests, but do not specify the precise location for measuring vibration. This study determined equivalent comfort contours for fore-and-aft vibration of the backs of seated persons from 2 to 80 Hz using the method of magnitude estimation, examining the effect of input location, contact area, and body posture. The equivalent comfort contours indicate decreased sensitivity to vibration acceleration at frequencies greater than 8 Hz. Equivalent comfort contours with a full backrest were similar to those with contact at only the highest location on the back. The derived frequency weightings are broadly consistent with frequency weighting W(c) but suggest somewhat greater sensitivity at frequencies greater than 30 Hz and vary in shape with changes in vibration magnitude. It is concluded that with low and moderate magnitudes of vibration the severity of fore-and-aft vibration of a backrest can be assessed from the frequency-weighted fore-and-aft acceleration measured at the highest point of contact between the backrest and the body if the frequency weighting W(c) is employed in the evaluation.
椅背的前后振动会影响全身振动相关的不适和受伤风险。相关标准（BS 6841:1987 和 ISO2631-1:1997）建议使用 W(c) 频率加权来评估椅背的前后振动，但并未指定测量振动的精确位置。本研究使用量级估计法，确定了从 2 到 80 Hz 频率下坐姿人员背部前后振动的等效舒适度轮廓，研究了输入位置、接触面积和身体姿势对振动的影响。等效舒适度轮廓表明，在高于 8 Hz 的频率下，对振动加速度的敏感性降低。有完整椅背的等效舒适度轮廓与仅在背部最高位置接触的轮廓相似。得出的频率加权与频率加权 W(c)大致一致，但在高于 30 Hz 的频率下灵敏度略高，并且随振动幅度的变化而变化。研究得出结论，如果在评估中使用频率加权 W(c)，则可以根据在椅背和身体之间的接触最高点测量的频率加权前后加速度来评估低强度和中等强度振动下椅背前后振动的严重程度。
