Research On Mechanical Properties Of 2D Plain Woven C/SiC Composite In Medium Temperature Under Oxidation Environment

Based on 400-900 Carbon fiber oxidation kinetics model,the dual-scale model is developed to predict the residual stiffness and residual strength of the material under non-stress oxidation environment by taking 2-D plain woven C/SiC composite as example.The model is applied to simulate the residual stiffness,residual strength of 2-D plain woven C/SiC composite under non-stress oxidation environment.In this paper,the residual modulus,residual strength of 2-D plain woven C/SiC composite are predicted and compared with the experimental data.The comparison results indicate that the model in this paper is reasonable.Besides,influences of oxidation time,oxidation temperature as well as other parameters on the prediction of residual axial stiffness,tensile strength are analyzed.Based on the analysis of mechanical properties of unidirectional ceramic matrix composite under stress-oxidation environment,the dual-scale model is established to predict the residual mechanical properties of 2-D plain woven C/SiC composite under stress oxidation environment.Considering the matrix cracking and oxidation damage at the micro-scale,the equal proportional reduction method is firstly proposed to calculate the residual axial moduli and tensile strength of the composites under stressoxidation environment.In this paper,the residual axial stiffness and residual tensile strength are compared with the experimental data,and the results show that the model is reasonable.Besides,influences of oxidation time,oxidation temperature,stress level and fiber volume fraction on the residual axial stiffness and tensile strength are analyzed.At last,based on the study of the hysteresis behavior of unidirectional ceramic matrix composites,the dual-scale model is established to predict the tension-tension fatigue hysteresis loops of 2-D plain woven C/SiC composites.The mass loss rate model is firstly combined with the hysteresis theory.The variation of the interfacial strength and fiber volume fractions is analyzed under the condition of fatigue oxidation.Besides,the influences of oxidation temperature,oxidation time and fatigue load on the hysteresis loops of the composite under high temperature fatigue oxidation environment are analyzed.