The sequential quadratic programming method is introduced in arch dam shape optimization design. In the optimization computation, the arch dam volume is taken as objective function, and the calculation is realized by automatically considering loading process, equivalent stress computation and simulation of shape optimization for arch dam based on FEM. A parabola arch dam is used as a numerical example. The result shows that the optimized figure is much safer and more practical, which indicates that the SQP method is an effective way for optimization design of arch dam shape.

To shorten calculation time in finite element simulation by using multithreading computer, a parallel algorithm for stiffness matrix decomposition based on threadpool method is proposed. Firstly, a decomposition method of applicability to parallel computation is put forward by transferring the Cholesky's LLT method. Then, the threadplool is employed to generate multithreading for repeating use and the optimization is conducted considering load-balancing of each thread. Finally, numerical tests by using proposed algorithm in decomposition of one-dimensional array stored stiffness matrix are carried out on different calculation platforms with multi-processors. It is shown that the parallel algorithm can overcome the limitations of OpenMP when being applied in nested loops and is of high efficiency on stiffness matrix decomposition with low platform demands. The algorithm has explicit concept and minor programming difficulty and is applicable to solve problems caused by limitation of OpenMP in particular.