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In order to take into account the local material non-linear elastic-plastic effects generated by notches, Glinka proposed the equivalent strain energy density (ESED) Criterion which has been widely accepted and used in fatigue theory and calculation for the last few decades. In this paper, Glinka's criterion is applied to structural optimization design for elastic-plastic correction to consider material non-linear elastic-plastic effects. The equivalent (fictitious) stress was derived from Glinka's Criterion equation for the commonly used Ramberg-Osgood and bi-linear stress and strain relationships. This equivalent stress can be used as the stress boundary constraint threshold in structural optimization design to control the elastic-plastic stress or strain in nonlinear optimization.

What is described is a new tool for creating parametric, concept-level FEA body models without waiting for geometry created in a CAD system. This has the obvious advantage of putting CAE in a position to lead the design activity instead of reacting to it. The process for creating the concept FEA models will be described along with a verification test case in which crash and stiffness results from the concept modeler are compared with FEA results created in the more traditional way using CAD data.

The noise within a car interior affects the customers' perception of quality, hence the need for noise control in cars. The arrival of structural finite element analysis (FEA) and acoustic boundary element analysis (BEA) has created the possibility of quickly performing many computational design changes. Thus, effective noise control solutions can be predicted without many vehicle prototypes. Computational analysis of the passenger compartment of an existing four-door car was performed to predict and reduce road noise. This analysis guided the development of structural changes that would reduce the sound pressure levels at the driver's and rear passenger's ear locations. Laboratory tests of these structural modifications in a prototype vehicle confirmed that the sound levels were reduced.