The report is concerned with the performance of occupant restraint systems (for example seat belts, collapsible steering columns or yielding padding) under conditions of frontal impact. Conditions for optimum system performance are established on the basis that injury is related mainly to the peak deceleration of the occupant. A mathematical model is proposed which enables peak deceleration of the occupant to be estimated rapidly. Typical results from this model are presented on graphs from which, for given impact parameters such as restraint stiffness and slackness, this peak deceleration may be found.
By treating restraint stiffness as a subsidiary parameter, which can always be given its optimum value, the effect is examined of design changes in the vehicle or in the shape of the restraint characteristics, particular consideration being given to the maximum system performance achievable by optimisation of vehicle deceleration pulse shape.
Throughout the report, graphs and other results are given in general non-dimensional form, which allows their immediate application to the design of optimum forms of seat-belts, safety belts, collapsible steering columns and the like.
