抄録
This paper presents an approach to minimize weight of structural material while keeping breaking strength base on a non-parametric shape optimization problem. As an index for the breaking strength evaluation, the maximum value of principle strain is used including large deformation range. Under assumption of monotonous loading, the hyper-elastic theory is applied in calculating the deformation of structural material in order to reduce computational time. To avoid difficulty of taking derivative, local functional are transposed to global integral functional using Kreisselmeier-Steinhauser (KS) functional. To improve convergence of the calculation, a new method to determine the parameter in KS functional which controls extraction ability of maximum principle strain value is introduced. The mass and the maximum principle strain evaluated by KS functional are chosen as an objective function and a constraint function, respectively. The shape derivatives of these functions are evaluated by the shape optimization theory. The traction method is employed to keep the smoothness of original boundary. An example of numerical calculation for a structural material model shows 10% of mass reduction while keeping the maximum principle strain constant.
