Development of frequency weighting function for Asian (Korean) people in vertical whole-body vibration; in comparison with ISO 2631-1

Abstract

In the field of ‘human vibration’, until now most frequency weighting functions have been derived from particular experiments whose subjects were only Western people. However, because of inherent differences (e.g., characteristic and shape of body parts, muscular and cellular tissue) between Western people and Asian people, frequency weighting function based on Asian people is required. An experiment was carried out to develop a frequency weighting function for the Korean people in vertical whole-body vibration, and to verify whether this weighting is acceptable in practical applications in comparison with ISO 2631-1. Ten male subjects of mean weight and height were tested for a posture similar to sitting in a passenger seat (footrest, upright and placement of the palms of hands on thighs, etc.) of a car. This experiment was performed using sinusoidal excitation in the range from 2 to 250 Hz, which was a combination of one-half and one-third octave bands at eight determined amplitudes. To guarantee the reliability and accuracy of the test, non-parametric statistics was adopted to resolve the fact that there was not enough of the sample. Furthermore, two methods were considered to make the frequency weighting function and equal sensation curves. The first method changes the amplitude at every fixed frequency, and the other assigns weighting values. Korean people showed the most sensitivity to vertical whole-body vibration at 6.3 Hz excitation, so much higher weighting factors than weighting factors of other frequencies must be assigned near that frequency.