Method for predicting residual tensile strength of ceramic-based composite material in stress oxidation environment

Abstract

The invention discloses a method for predicting the residual tensile strength of a ceramic-based composite material in a stress oxidation environment. The method comprises the following steps: determining a change rule of a one-way SiC / SiC composite material SiC matrix saturated crack spacing and a SiC matrix crack average spacing along with stress; determining the change rule of the SiC matrix crack width along with the stress and the temperature; acquiring oxygen concentrations at different positions in the material at different moments and solving the change rule of the interface consumption length and the thickness of the surface oxide layer of the SiC fiber at the crack along with stress, temperature and time; obtaining the axial stress distribution of the SiC fiber; determining the size of oxidation defects on the surface of the SiC fiber; deducing a SiC fiber characteristic strength distribution expression; deducing a SiC fiber breakage probability expression; acquiring the maximum stress in the bridging SiC fiber; solving the SiC fiber fracture probability under certain temperature, stress and oxidation time; obtaining the residual strength of the material. According to themethod, the residual tensile strength of the unidirectional SiC / SiC composite material at each moment, each temperature and the tensile stress level can be accurately predicted.

Description

technical field [0001] The invention belongs to the technical field of material tensile strength prediction, in particular to a method for predicting the residual tensile strength of a ceramic matrix composite material in a stress oxidation environment. Background technique [0002] The high temperature resistance, low density and high [0003] Excellent properties such as specific strength and high specific modulus make it one of the irreplaceable new high-temperature structural materials in the aerospace field. It is widely used in aviation and aerospace engine hot-end parts, aerospace back-and-forth heat protection systems, high-speed brakes, and gas turbine hot-ends. components, high temperature gas filtration and heat exchangers, etc. [0004] Under service conditions, SiC / SiC materials need to withstand the joint action of stress and oxidation coupling. When the material is subjected to a certain tensile stress, cracks will appear in the SiC matrix, and the cracks wi...

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Problems solved by technology

[0008] The present invention aims at the deficiencies of the above-mentioned prior art, and provides a method for predicting the remaining tensile strength of the ceramic matrix composite material in a stress oxidation environment, so as to solve the problem in the prior art that the unidirectional SiC / SiC composite material cannot be accurately predicted in the stress oxidation environment. Ambient Residual Tensile Strength Issues

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