The Analysis Of Residual Stress For Functionally Graded Material

Composites have been widely used in actual engineering. The stress concentration problem appeared when the temperature changed a lot for some general composites. It comes from the different thermal expansion coefficients of the components. Functionally graded materials(FGM) continuously change their microstructure of components, which can make the interface between different components vanish, then, residual stresses are reduced, and the problem mentioned can be solved.Wakashima power function model was used for simulating the distribution of FGM's components in the thesis. Mixed-mode method and the improved method were used for predicting the valid elastic modulus and poisson ratio of FGM. Based on continuum mechanics and small deformation theory, establish thermoelastic analytical model of FGM, which is used for calculating the distribution of residual stresses.Applying the model, processing residual stresses of W/Cu FGM were calculated at different conditions including composition distribution, the number of graded layers and the thickness of pure metal layer. Then, the best composition distribution exponent of W/Cu FGM was given in the dissertation. Applying ANSYS, we obtained the similar results. Besides, we also considered the edge effect in the analysis.ANSYS can be used in analysing the residual stresses in FGM, material properties change with position continuously in FGM, which can be only approximatively simulated as many same properties layers in ANSYS programs. The analysis process need to set up the property parameters many times, which makes the analysis fussy. The method in this thesis is more suitable for those FGM with simple structure. By setting up some simple parameters, it can simulate the residual stresses of FGM with different laminated structures. All the results are valuable for FGM's design and optimization.