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Stochastic simulation is used to account for the variation in the manufacturing and assembling processes of the vehicle structure and occupant restraint system. An integrated full vehicle model with belted driver, 50th percentile male Hybrid III dummy, subjected to a 35 mph zero degree impact test, is used to present the scatter in the vehicle crash and occupant restraint performance. Yield stress of a typical mild steel has scatter values between 10 to 20% and a coefficient of variation of 5% is derived for scaling the stress and strain curve. The thickness tolerance has scatter values specified between 5 to 10% and a coefficient of variation of 2% is used in the study. The material properties and thickness of major structural components for absorbing impact energies, such as the motor/occupant compartment rails and upper rails, bumper beam, cradle, and toe pan are the random input variables for the structure.

In quasi-static tension and compression tests of thermoplastics, full-field strain distribution on the gage section of the specimen can be captured using the two-dimensional digital image correlation method. By loading the test specimens made of a talc-filled and impact-modified polypropylene up to tensile failure and large compressive strains, this study has revealed that inhomogeneous deformation within the gage section occurs quite early for both test types. This leads to the challenge of characterizing the mechanical properties - some mechanical properties such as stress-strain relationship and fracture strain could depend on the measured section length and location. To study this problem, the true stress versus true strain curves determined locally in different regions within the gage length are compared.