The automatization of crack expand simulation is carried out by the programmer, using the simulation technique of singular unit, base on the ANSYS software. The nodes are dispersed by crack front. The singular unit is using to radiate from the nodes. The restriction is used at the edge of model. The stress intensity factor is worked out. The expansion ratio is confirmed. Then the displacement of crack expansion of the nodes is resolved. The way of expansion of crack front is orthogonal. The semi-ellipse curve of crack expand is worked out by numeric analysis. The simulation of crack expansion is carried out. The system of MTS（Material test system）810 from USA is used. And the experiment of crack expand is carried out with the load of tension. On the other side, the new crack front is fitted to get continual extension simulation.

A method for combining the FEA softwares, I-DEAS and MSC.Marc, with the iSIGHT design platform is presented to optimize die –pressing (DP) process. In the optimization design, two kinds of optimization algorithms, genetic algorithm (GA) and sequential quadratic programming (SQP), are employed. The result reveals that the residual stress is minimum under conditions that die rake angel equals to 48.50, dieing depth1.9, and friction factor 0.065. The above results give preference to design dieing form tools and process parameters.

The 3D finite element simulations are conducted for the cold working of a fastener hole in a low carbon steel plate. The simulation models the actual cold working process where the hole edge is chamfered with die-press. The agreement of finite element method and experimental results is good enough. The residual stresses are analyzed under the different die-press parameters and contact conditions i.e. die-pressing depth, friction factor, the die taper. The main results in this work are as follows: With increasing in chamfer depth the maximum compressive residual stress shows an increasing within the chamfer range of C1.5; the compressive residual stress is decrease with increasing friction; with increase in die taper the maximum compressive residual stress shows the slow increase. The efficiency for enhancing the load-carrying capacity of structural components with cylindrical holes subjected to bending load has been proved by means of FE simulation. The study shows that the simulations of cold working are necessary for if predicted residual stresses are to be used to assess fatigue life and for design die-pressing tool, improvement of parameters of the process of DP working.