Shape optimal design of a spacer grid design

The full text follows. A shape optimal design method is adopted for a spacer grid strap. It is made of punched sheet metal process, functioning as springs and dimples supporting fuel rods. For stress analysis of the assembled fuel rod support, a typical cell out of the repeated pattern in the assembly is modeled using 4-node shell elements. A commercial code, ABAQUS, is used for detailed stress analysis. For the optimization, design variables are taken from geometric parameters representing the shape of the bent leaf spring part. Objective function is considered in relation to mechanical functions. Maximum von-Mises stress is also considered. (authors)