THE EFFECTS OF VERTICAL AND HORIZONTAL VIBRATIONS ON THE HUMAN-BODY

Vertical and horizontal vibrations of a 700 kg human have been investi gated. A new mechanical model has been developed, and an analogous ele ctric simulation has been carried out, which in turn has been analysed by wing computer software (MICRO-CAP II). The vibration force comes f rom (a) hand, (b) seat and (c) a combination of the two. The theoretic al results obtained have been tabulated and are presented in a graphic al manner. It has been found that the body segments (lower arm, head, torso, cervical spine and lumbar spine) are affected by horizontal vib rations when the input force (F-i) comes from both hand and seat more than when (F-i) comes from the seat alone. Similar results have been f ound also for the case of the lower arms and torso when the body is su bjected to vertical vibrations. The head is affected by vertical vibra tions when (F-i) comes from the seat more than when (Fi) comes from bo th hand and seat. An experimental set-up has been designed and measure ments of vibrational signals from the human lower arm, head and torso have been carried out. Similar trends are shown for both theoretical r esults and experimental findings.