| The problems of engineering structures can be better calculated with the advances in technology and the extensive application of computer-aided software. At the same time, more and more demands of the design, modification and optimization of large-scale engineering structures arise as the large-scale and complicated engineering structure are required. The reanalysis method can significantly reduce the computational cost of the design and optimization of the large-scale structure, thus it attracts much attention and gets rapid development. However, the specific applications of reanalysis method, especially the applications to practical engineering combined with large-scale finite element software are rare. This is mainly because the current finite element software seldom has the properties of rapid reanalysis. Although the properties of the design and optimization of some finite element software (such as ANSYS) are powerful, the reanalysis of them are basing on the Taylor series expansion method. The computational time of reanalysis is unbearable especially for the large-scale problem when the finite element software is directly employed for the design of the structure. Therefore, the seamless method which combined the popular reanalysis method with the finite element software is urgent and applies the reanalysis method to practical engineering problems with the minimal development costs.This thesis is focusing on the problem which seamlessly connects the reanalysis method with the popular finite element software. The method which seamlessly combined the preconditioned conjugate gradient (PCG ) method with ANSYS is proposed, and the analysis procedure which is carried out for reanalysis utilizing ANSYS is indicated in this paper. The necessary sub-module for static reanalysis under ANSYS environment is exploited. The main work is listed in the following:1. The method which applies UIDL to graphical user interface is given for facilitating designers to modify and design.2. The method which establishes the modeling by the parametric APDL is proposed for structural optimization.3. The reanalysis module which utilizes the PCG method with UPFs compilation by ANSYS is given for efficient reanalysis.The preconditioner is selected as the initial stiffness matrix in the PCG method.The PCG method which is programmed by FORTRAN 90 is seamlessly linked to ANSYS by utilizing the secondary development function of ANSYS in this thesis. The superiority of PCG method and the pre-and post processing function of ANSYS can be employed for dealing with the static reanalysis problem of large-scale and complicated structure in practice. The specific process is as follows: The details are in the following:①. Start ANSYS. Here the ANSYS program has already been linked to reanalysis module by utilizing UPFs after compiling.②. The finite element model is established for initial analysis, loaded and solved. The direct solution method is selected for obtaining the preconditioner K 0 in order to using reanalysis method.③. The structure is modified. The dynamic modification can be carried out by the user's own custom toolbar buttons. For example, the MATPROP buttons are given in the following figure:The stiffness matrix after modification is extracted. The command WRFULL is used before solving for the modified structure. This command is stopped after assembling stiffness matrix in ANSYS, and can obtain a file which has the suffix full.The storage of the file is the stiffness matrix K after modification.④The reanalysis is carried out by PCG module. The required preconditioner in this procedure is given in step②. The file which contains the displacements results has been obtained after reanalysis.⑤. The displacements results are obtained, analyzed and saved in the file which has the suffix full in order to be looked over or called.⑥. The displacements results are returned to ANSYS and post-processed. Numerical examples have illustrated that this method can efficiently and accurately deal with the reanalysis problem.
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