Equivalent method for cross-scale thermal analysis of fiber toughening composite material based on multiple criteria such as cross entropy and the like

Abstract

The invention discloses an equivalent method for cross-scale thermal analysis of a fiber toughening composite material based on multiple criteria such as a cross entropy and the like. The method comprises the following steps: establishing a random representative unit and enabling CMC fiber reinforcement phases to be randomly distributed by utilizing a Monte-Carlo method in the unit; establishing SRVEs for multiple times and performing finite element simulation on the SRVEs to obtain statistic data of thermal physical quantities such as an equivalent heat conduction coefficient of the composite material, a material temperature gradient field and a thermal flux density field; and adjusting the size of a PRVE, determining the critical size of the PRVE after multiple convergence criteria such as a mean value, a variance, the cross entropy and the like of the thermal physical quantities are met, obtaining the distribution of the equivalent heat conduction coefficient of the composite material, the material temperature gradient field and the thermal flux density field, and establishing a corresponding relationship between a microscopic structure and a macroscopic property. According to the method, heterogeneous characteristics and existent physical dispersity in the composite material are fully considered and judgment bases are provided for how to determine the critical size of the PRVE in thermal analysis of the composite material, so that the corresponding relationship between the microscopic structure and the macroscopic property can be established more accurately.

Description

Technical field: [0001] The invention relates to an equivalent method for cross-scale thermal analysis of fiber toughened composite materials based on multiple criteria such as cross entropy, which belongs to the technical field of engineering thermophysics. Background technique: [0002] With the development of industrial technology, various composite materials have been widely used in various industrial fields, especially in the field of aerospace. Taking ceramic matrix composites as an example, as a non-metallic material, compared with commonly used metal materials and polymer materials, it has excellent properties such as high temperature resistance, wear resistance, and corrosion resistance, so it has attracted more and more attention. . However, limited by its brittleness, ceramic materials lack sufficient strength and reliability when used on stressed structural components such as engine turbines, so they cannot be directly applied. At present, it has become one of ...

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Problems solved by technology

However, the actual complex structure inside the actual CMC material makes it extremely difficult to obtain a single type of RVE, and whether the RVE criterion established in some existing mechanical property research fields can be directly applied to the field of thermal analysis, or how to improve it, no scholars have carried out related proof work

At the same time, the fixed value of thermal conductivity obtained by using a single RVE cannot fully reflect the characteristics of the dispersion of physical properties of CMC materials.

The existence of these problems makes the RVE method still have certain deficiencies in the thermal analysis of composite materials.

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