Shape optimization for two-dimensional continuum based on two-phase control strategy

Two-phase control means that middle-variables are inserted between natural design variables and nodes in the mesh. Two-phase control is established: 1) The coordinates of the key points are controlled by natural design variables; 2) The nodes in the FEM mesh are controlled by key points. The second control describes the design elements in terms of the shape function of FEM and the parameter coordinates are introduced. Then the sensitivity analysis, the control of change of structural shape and its mesh are realized. On the base of the two-phase control, some difficulties in the problem of shape optimization can be solved and the problem is approached as a Sequential Quadratic Programming problem to be solved. The program of shape optimization is carried out on MSC/PastraneV-Nastran platform and by using PCL language. The idea of the research is verified by some examples. The reliability, the accuracy and the high-efficiency of the program have been testified by the results of the examples.