Industrial and Management Systems Engineering


Date of this Version



A Thesis Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Industrial and Management Systems Engineering, Under the supervision of Professor David Cochran. Lincoln, Nebraska: December, 2010
Copyright 2010 Mohamed Amar


This study attempted to estimate the damping properties of human tissue by using spring and damper system as a model. Data of impacting human tissue at the deltoid area was used to obtain a continuous, second order system to represent the mass-spring-damper system. A discrete ARMA(2,1) model was fitted using the data obtained from experiments in which the deceleration of a pendulum impacting human shoulders in the area of the deltoid muscle was measured. The data of the deceleration was integrated twice to obtain estimates of displacement. The integration was done until the maximum displacement occurred at zero velocity.

An ARMA (2, 1) model was then fitted on the displacement data using the Data-Dependent-System (DDS) technique. The results were then converted to a continuous second order autoregressive model A(2) using the concept of Green’s Function and the auto covariance. Utilizing the principles of a mass-spring-damper system enabled the estimation of the spring constant (K) and damper constant (C) for each trail of the experiment. Estimates for both constants were found to be highly correlated with the mass of the impacting pendulum. Explanations for this string relationship were investigated.