Some Applications Of Finite Element Method And FEM Software

This paper mainly presents the application of finite element method. Firstly it introduced the plastic buckling and post-buckling occurred in the transition region in pressure vessel, analyzed by FEM. The arc-length method and RIKS procedure was employed to simulate the deformation process, and an initial localized geometrical imperfection determined from the elasto-static deformation was introduced into the computational model. ABAQUS was used to analyze buckling pressure. The results shows, the initial buckling load is quite sensitive to the artificial geometrical imperfection, however, the post-buckling load is not so sensitive to it. After the first buckling initiated, the succeeding loading leads to more wrinkles within the compressive transition region, which is similar to what observed in the pressure test. The results also show that the radius of the transition region fairly affects the buckling load. The buckling load is larger with relatively bigger value of the radius.The paper also predicted the material elastic modulus and Poisson's ratio of lung tissue, an objective function for inverse analysis was set up, and an inverse analysis scheme of step-by-step gradient approximation was formulated. The gradients of the objective function were approximated by the relevant differences based on the results of finite element analysis. An example was presented to demonstrate the validity of the present method. From CT images, the 3D model of the lung tissue and tumor were re-constructed, and also the displacements of boundary points and those of internal sample points were separated. Reasonable results of the material parameters are obtained by the inverse analysis.