DEVELOPMENT OF OCCUPANT MULTIBODY MODEL FOR VEHICLE RESTRAINT SYSTEM IN FRONTAL IMPACT

Abstract

The thesis aims to study the theoretical model of vehicle occupant and to nd chances of injury using the passive safety component i.e. seat-belt and airbag. To reduce the e ect of injury key variable are force applied on the head and the chest thus giving head injury criterion and thorax injury criterion. Lagrangian dynamic equation is used to develop equation of motion of the vehicle occupant. The occupant head and thorax position is obtained based on the forces acting on the occupant during di erent phases in a crash. The seat-belt control force model is developed for sinusoidal vehicle collision, this is an important aspect as very large seat-belt force may cause head to rotate and injury parameters go beyond the safe limits of injury criterion. The occupant model is solved for time steps in MATLAB. Airbag plays an important role in protecting the occupant when seatbelt cannot restrain the occupant alone. So an e ort is made to study the dynamic behavior of occupant when it make an impact with the airbag as the demand of enhanced deceleration system capable of stopping occupant in shorter distance is very high. For this mathematical model of airbag and it's FEA simulation in ABAQUS is done. Mathematical modeling of elliptical and trapezoidal cross section is done for impact case in vertical direction. FEA simulation is performed by using shell element for the airbag. Velocity and acceleration pro le of impactor is obtained by using nodal values