13th International Conference on Fracture June 16–21, 2013, Beijing, China -3- this value is discrete for 10 steps as the coupled sub-timestep. The total time of the solid analysis and the fluid analysis should be same as the coupled time. 2.3. Process of Fluid-Solid Coupled Analysis Based on ALE ANSYS Coupling control MFX controler CFX_pre CFX.def Solid.cdb Solid.dat Fluid domain Boundary condition “Interface1” Solver control Output control Feature-based parametric FE modeling Solid domain “Interface1” Null DZ125 Solid 185 Surface shell 154 Coupling flag “1” Solver control Interface Remesh of fluid field Boundary condition Figure.1 Process of the fluid-solid closely coupled analysis Considering the inheritance of the analysis method, the paper establishes the flow of a fluid-solid closely coupled analysis on the turbine blade shown in figure 1, when the method of the parametric FE modeling based feature solves remeshing on the solid domain. The solid domain uses the ANSYS, while the fluid domain employs the CFX. The research process is steadily forward when every solver gets convergence. The mesh fairing method solves the mesh move. The coupled control does not only solve the conversion between the Eulerian coordinate system and the Lagrange coordinate system, but also transfers the pressure and the solid displacement. The MFX controller links solution files of two domains. The CFX.def contains fluid domain solver, while the solid domain file is divided into the model file (Solid.cdb) and the coupling file (Solid.dat). Finally, a batch is employed to call for each module of the process. 3. MDO technologies The basic idea of the VCM [11] is: how to effectively use various precise models and bring the feasible solution based on the less cost. The traditional VCM mainly concentrated in both of the high and low precise analysis. The low precise model could improve the optimization efficiency, while the high precise analysis is responsible for introducing the correction factors which would enhance the precision of the results from the low precision during the cycle. Meanwhile, the correction factor is updated after several optimization iterations called interval method [12]. Thus it could be seen that the traditional VCM mainly includes two kinds of precision, the correction factor and the interval method. The paper will modify these three aspects so as to enhance the model management ability and adapt the higher precise method. 3.1. Various precise models Set x as design variable. h( ) f x indicating the response of the coupled analysis in this paper is the high precise results; l ( ) f x on behalf of the single discipline analysis response is the moderate
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