A method for optimal design of automotive body assembly using multi-material construction

This paper proposes a new method for designing lightweight automotive body assemblies using multi-material construction with low cost penalty. Current constructions of automotive structures are based on single types of materials, e.g., steel or aluminium. The principle of the multi-material construction concept is that proper materials are selected for their intended functions. The design problem is formulated as a multi-objective nonlinear mathematical programming problem involving both discrete and continuous variables. The discrete variables are the material types and continuous variables are the thicknesses of the panels. This problem is then solved using a multi-objective genetic algorithm. An artificial neural network is employed to approximate the constraint functions and reduce the number of finite element runs. The proposed method is illustrated through a case study of lightweight design of an automotive door assembly.