A STUDY ON VIBRATING MODEL OF HUMAN BODY UNDER SITTING AND OTHER POSTURES

Abstract

In this thesis, modeling of vibratory system of human body and its study under sitting postures has been presented. The human body. is devloped as a spring-mass system. A generalized procedure for the vibratory modeling through anthropomorphic model and assumptions underlying are clearly stated. The inertial and stiffness values of the segments are obtained using anthropmetric data and elastic modulii of bones and tissues. The validation of our procedure is done by developing the model for a 50th percentile U.S. male and comparing the resonance frequency with some experimental data of U.S. male available in the literature. As an illustration of modelling procedure, two models of 16 degree of freedom of body corresponding to two sitting postures are considered. System natural frequencies and corresponding normal modes are evaluated by generalized Jacobi Method. Local natural frequencies are estimated by eigen vectors and verified by calculating frequencies. keeping other masses as fixed. In addition, this thesis presents frequency response of different parts of body due to constant amplitude excitation at the support in the vertical direction. In this thesis efforts have been made to refine the work of Dr. Nigam and Dr.Malik by taking suitale spring combination of the segments in the model and by hypothetical combination of elastic modulii of bones and tissues. Since In-vivo and In-vitro studies do have its obvious limitation. This has led to (v) (vi) development of analytical method. Therefore, the thesis seems to have achieved its objective with a fair success. However, there is further wide scope for refinement in future to take various consideration into account, since human body is a complicated biomechanical system