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In vehicle crash tests, an unbelted occupant's kinetic energy is absorbed by the restraints such as an air bag and/or knee bolster and by the vehicle structure during occupant ride-down with the deforming structure. Both the restraint energy absorbed by the restraints and the ride-down energy absorbed by the structure through restraint coupling were studied in time and displacement domains using crash test data and a simple vehicle-occupant model. Using the vehicle and occupant accelerometers and/or load cell data from the 31 mph barrier crash tests, the restraint and ride-down energy components were computed for the lower extremity, such as the femur, for the light truck and passenger car respectively.

Computer simulations of occupant dynamics in frontal crashes have pretty much been done like sled tests, in that crash-induced deformation of the interior — which may be significant for the occupant — has usually not been accounted for. The object of occupant dynamics simulation studies is often to assess the effect of changes in vehicle front-end parameters on occupant response. But these parameter variations may influence the amount of interior deformation. In order to simulate more accurately occupant dynamics in very severe crashes, the interior deformation caused by engine intrusion should concurrently be simulated. Crash test results over a range of speeds were used in a computer simulation study of occupant compartment intrusion in high speed barrier crash tests. It was found that intrusion has a significant effect on occupant response and where appropriate should be included in crash simulations.

This paper describes an interactive graphics processor, VIEW2D, for the MVMA-2D occupant crash simulation model. VIEW2D simplifies the use and operation of the MVM-2D by processing and displaying any of the hundreds of input and output response variables. VXEW2D displays the occupant and vehicle interior on a graphics terminal before program execution for verifying or revising the input data file. It also displays the kinematics and the dynamic responses of the dummy and vehicle at times selected by the user. The main functions and features of V1EW2D are described, and the procedures to make animation on a graphics terminal with refresh mode are presented. Finally, to illustrate the applications of the MVMA-2D and VIEW2D, a study of front structure intrusion effects on occupant kinematics and dynamic responses is discussed.

The vehicle-occupant impact dynamics during a crash are studied using a simple mathematical model. The model yields explicit analytical relationships between occupant responses and physical parameters of the vehicle structure and occupant restraint system. These parametric relationships, verified by experimental crash tests of the total system, are useful in describing the physical concepts of the impact event, and predicting occupant dynamic behavior during a vehicle crash. The limitations of the model are discussed and the design procedures using the equations and “carpet” plots are presented to aid the designer in the selection of a restraint system and vehicle structural parameters to meet predetermined design criteria. The application of the “carpet” plot in studying the sensitivity of the occupant response to the vehicle structural parameters is also demonstrated.

It is frequently desirable to construct a characterization of vehicle deceleration which is significantly simplified from its actual time history. A number of interesting techniques have been developed to perform this characterization based upon polynomial and Fourier-type series approximations and utilizing goodness of fit criteria related to both least squared error and the satisfaction of boundary conditions. Extensive mathematical occupant simulations indicate that characterizations involving as few as four parameters are adequate to describe the primary effects of complex vehicle deceleration time histories as they influence occupant dynamics with conventional restraint systems.