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This report describes an experimental validation of an ellipsoid-to-foam contact model. A series of static foam tests was conducted using Side Impact Dummy rib cage, pelvis, upper leg, and wooden ellipsoids as impactors to validate a theoretical foam contact model previously developed. Predicted results of contact forces, calculated using the uni-axial stress-strain relationship and contact areas, yield good correlation with the test data. These studies used CFC foams and were conducted prior to switching to water-blown foam material development. The ellipsoid-to-foam contact model is being integrated into a MADYMO side impact model. The MADYMO/foam simulation model can then be used to help evaluate design variable tradeoffs (e.g., door thickness vs. body side structures and foam padding requirement vs. interior package) thereby reducing the current dependency on testing, bolster development time, and cost.

This paper deals with the constitutive modeling of energy absorbing foams. Two mechanical-analog hyper-elastoplastic models are constructed for simulating the characteristics of semi-rigid and rigid foams. These piecewise linear models are suitable for describing the loading as well as the unloading behavior of material. The result from quasi-static compression tests are used to determine the three parameters of the models. It is observed that the models can be used in the prediction of stress-strain behavior as well as the energy absorption characteristics.