Vibration Effect on Human Subject in Different Postures using 4-Layered CAD Model

Abstract

A human body gets exposed to vibration in their daily life due to multiple works like working on the machines, traveling, riding, escalators etc. Due to which people feels discomfort during working that causes bad impact on human body in various ways i.e. back pain, headache, hand sensation etc. In this study, harmonic analysis has been performed on the 3D CAD model of the 76 kg 4-layer (bone, organs, muscle and skin) of human subject in standing and sitting posture by considering 95th percentile anthropometric data of Indian male population. In standing posture, the human subject has been standing on the floor at excitation magnitude of 1 m/s2 with damping ratio 0.337 between frequency ranges 0-20 Hz under vertical vibration. Feet to head transmissibility has been performed from feet to head in standing and seat to head transmissibility has been performed on the human subject in sitting posture in different inclination angle is 0˚, 12˚ and 21˚ on the automotive seat. The Polyurethane foam has been considered for the seat cushion as seat pan cushion and backrest cushion to increase the comfort level for human body during traveling. The biomechanical and physical properties of the human subject that include properties of bones, organs, muscles and skin along with other accessories i.e. seat and backrest cushion have been taken from existing literature. The maximum effect has been found at lower arm, head and organs of the human body between the frequency ranges 4-8 Hz and decreases continuously due to the biodynamic properties of the human solid model and seat cushion model. This study shows that results are approximately nearer to validated results and cushion material has good shock absorber property. There observed a less effect of vibration without seat suspension system and also, inclination of the backrest can improve the comfort level during riding by the vehicles.