Influence of Pre-stressed Parts in Dummy Modeling - Simple Considerations

New regulations and consumer tests for passive safety in passenger cars have increased the demand on accurate models for occupant analysis. Thus, effects that have been neglected or modeled rather coarsely in recent occupant models might necessitate a more detailed modeling in order to capture the dummy behavior sufficiently accurate. This paper contributes to the discussion of the importance and the modeling techniques of prestressed parts in dummy models for occupant analysis. The authors present solutions provided by LS-DYNA to handle the pre-stressed parts like mapping, pre-simulation, or implicit time-stepping for positioning. Finally, the paper discusses sources of pre-stress in different parts of side impact dummies (SID), Hybrid III adult and child dummies. With simple examples the influence of the pre-stress is estimated.