Coupled Elasto-Plastic And Damage Analysis Of Functionally Graded Material

With the progress of science and technology, the Functionally Graded Materials(FGM) made of metal and ceramic are paid more attention to. The FGM have the advantages of both the high strength and toughness of metals and the high temperature and corrosion resistance of ceramic. So, research about the FGM is more and more. Stepped construction is used in the most research about the FGM and the fracture behavior is the basic research content. Before the FGM get to the fracture failure, inner hypoplasticity damage plays an important role. In this paper, a method of damage mechanics which is closer to the actual failure process of materials is used in the analysis of FGM with continuously changeable material properties.The FEM software ABAQUS is fit for dealing with nonlinear problems, and there are some user subroutine interfaces with which the ABAQUS main programs can be expanded. For the FGM, there are no material properties and suitable damage constitutive model in ABAQUS. So, the UMAT interface is used in the secondary development of ABAQUS.Firstly, ABAQUS is used in the elastic-plastic analysis of metal materials and the results are compared with that calculated by UMAT program to analyze the feasibility and reliability of UMAT subroutine. Then, a more practical linear strain-hardening plastic analysis method is used in the strain analysis of FGM with specific gradient index. The analysis method which elements are analyzed before the entirety is used in the whole process of the elastic-plastic analysis of FGM to make sure the result is accurate. The elastic-plastic damage coupling analysis to FGM is carried on, and the degree of damage with different gradient indices is simulated. The primary works in this paper expand the range of applications of ABAQUS and provides a reference to the design of FGM.