Abstract: To overcome difficulty of high computational cost in difference sensitivity analysis, efficient derivatives are obtained using “approximate-difference” strategy based on combined approximation method. Combined approximation method is fit for reanalysis in both temperature and thermo-structural analy-sis models, and accurate sensitivity is obtained under small disturbance which is verified by numerical examples. Virtual displacements of control point are selected as design variables, shape optimization model of thermo-structural steady response is established. Some numerical examples are provided and re-sults are discussed. Results are shown to demonstrate the feasi-bility and validity of the proposed method and model.

Key words: Approximate reanalysis, Combined approximations, Sensitivity analysis, Shape optimization, Thermal response, Thermal stress