Abstract:

Using the element strain energy density theory, combining with the real body-in-white(BIW) structure, a structure modification method based on the relative sensitivity,i.e., the ratio of the strain energy density to the mass sensitivity, was proposed. In accordance with a finite element model of a BIW, the relative sensitivities of the all thinwalled components of the BIW were calculated and the results were compared each other. The components with higher relative sensitivities need to increase their thickness, otherwise to decrease it, to achieve the structure with high stiffness and light weight. There modification schemes to achieve different targets were presented from the analysis based on the relative sensitivity:high stiffness scheme, light weight scheme, and tradeoff scheme. The comparison on the results of stalic sliffness calculation showed that the tradeoff scheme leads to a satisfactory modification results, is the best BIW structure model to neet the design requirements.

Key words: mechanical design, body in white, strain energy density, relative sensitivity, light weight structure