Multi-scale Simulation Of Failure Of 2.5D C/SiC Composites With Perforated Joints

Owing to their high strength,high modulus,low density,high temperature resistance and ablation resistance,ceramic matrix composites(CMCs)are the materials with high potential for use in high-temperature parts of aeronautical vehicles,e.g.,exhaust cone of engine.Due to the different functions of the various components in the aero-engine,the CMCs need to be connected to the metal structure,and the strength problems of the CMCs and the metal connection structure need to be studied.Mechanical connection is the main connection method between the CMCs and the metal connection structure,where CMCs need to be opened.The strength and failure modes of CMCs perforated joints need to be studied.In view of the research status of the strength analysis of CMCs connection structure by domestic and foreign scholars,the multi-scale calculation method was mainly used to analyze the strength and failure modes of CMCs.In this paper,based on the meso-structure of 2.5D C/SiC composites,a mesoscopic model including internal structures such as warp,weft,matrix and pores was established.A multi-scale calculation method based on sub-model technology was proposed to combine with the macro model and the meso model.The strength calculation and failure modes analysis of CMCs with orifice plate were performed by the progressive damage method.And the failure process of macrostructure and meso-structure was simulated respectively.The joint structure of CMCs and metal pins was tested in tension modes.The failure strength of the structure was obtained and the damage modes of the hole edge were observed by DIC.It was observed that the failure of contact area between the pin and the hole was the main reason for the crush failure and shear failure of the joint structure.Lately,the simulation calculation of the joint structure was compared with the experiment.The results show that failure modes of hole edge of CMCs is consistent with the experiment.The failure analysis of CMCs with orifice plate agrees well with the test of CMCs/metal pin connection structure,which verified the validity of the model and calculation method established in this paper.And the failure analysis method of CMCs connection structure is improved.