Method for calculating residual strength of ceramic-based composite material in high-temperature stress environment

A composite material and strength calculation technology, applied in calculation, computer-aided design, design optimization/simulation, etc., can solve problems such as the inability to consider the influence of residual tensile strength

Active Publication Date: 2019-10-18
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

[0010] In view of the fact that the existing prediction methods cannot consider the influence of non-uniform oxidation on the residual tensile strength of the overall material, a method for predicting the residual tensile strength of unidirectional C/SiC composites under high temperature (900-120

Method used

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  • Method for calculating residual strength of ceramic-based composite material in high-temperature stress environment
  • Method for calculating residual strength of ceramic-based composite material in high-temperature stress environment
  • Method for calculating residual strength of ceramic-based composite material in high-temperature stress environment

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Embodiment 1

[0227] The residual tensile strength of the unidirectional C / SiC composite material predicted by the method of the present invention is further explained in a high-temperature stress environment:

[0228] In the specific implementation steps, the environment is an air environment under standard atmospheric pressure, the temperature is between 900-1200°C, and the residual strength of the material under tensile stress of 69MPa and 172MPa is predicted. C fiber is T700 produced by Toray Corporation of Japan, and the material parameters of fiber, interface and matrix are shown in Table 1:

[0229] Table 1 Material parameters

[0230]

[0231] Step 1: Determine the change law of oxygen concentration inside the material

[0232] Oxidation kinetic model based on C / SiC composites in high temperature environment:

[0233]

[0234] and its boundary conditions:

[0235]

[0236] In formula (1), y is the coordinate value along the depth direction of the matrix crack, is the d...

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Abstract

The invention discloses a method for calculating the residual strength of a ceramic-based composite material in a high-temperature stress environment. The method comprises the following steps: determining an oxygen concentration change rule in the material; determining a change rule of a fiber oxidation notch; determining the number of oxide layers and the total number of fibers; determining fiberstress distribution before oxidation; determining a tensile strength model of the material before oxidation; determining a fiber tensile strength change rule in the oxidation process; determining thefracture proportion of the fibers in the oxidation process; determining fiber tensile fracture probability and fiber stress distribution in the oxidation process; determining the change rule of the oxidation fracture time of each layer of fibers; and determining the change rule of the tensile strength of the material in the oxidation process and the residual life of the oxidized material. The method provided by the invention can truly and effectively predict the morphology change of matrix oxidation and fiber oxidation, and can reflect the macroscopic properties of the material from the mesoscopic scale.

Description

technical field [0001] The invention relates to a method for calculating the residual strength of a ceramic matrix composite material in a high temperature stress environment, in particular to a method for calculating the residual tensile strength of a unidirectional carbon fiber toughened silicon carbide ceramic matrix composite material in a high temperature (900-1200°C) stress environment Calculation method. Background technique [0002] Carbon fiber reinforced silicon carbide ceramic matrix composites (Continuous carbon fiber reinforced silicon carbide composites, hereinafter referred to as C / SiC) is a new type of high-temperature structural material for the hot end parts of aero-engines. It has high specific strength, specific stiffness and other characteristics, and can effectively realize Weight reduction of hot end components. However, the hot end parts made of C / SiC will be affected by oxidizing gas and load during service, which greatly reduces their mechanical pr...

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F2119/06G06F30/20
Inventor 孙志刚陈鹏陈西辉宋迎东牛序铭
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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