MEASUREMENT AND INVESTIGATION OF APPARENT MASS OF A HUMAN BODY AT THE SITTING POSTURE IN A PASSENGER CAR

摘要

This study aims to measure an apparent mass of a seated human body at the sitting posture in a passenger car in the frequency range from 1 to 20 Hz and to compare the dynamic characteristics with those acquired from the erect posture. Thirty subjects joined the test where each of them were exposed to seven levels of acceleration from 0.2 m/s{sup}2 to 1.4 m/s{sup}2. Apparent mass curves measured at the hip contact point showed two peaks, of which frequencies are about 5 Hz and 12 Hz respectively. Frequency of the first peak was found to decrease with the increase of vibration magnitude. The second peak was dominant at the smallest vibration magnitude and got to disappear as vibration increases. The shape of the curve at the biggest vibration magnitude was very similar to that from the erect posture as sown in ISO 5982, but became different as the vibration level decreased.