Method for predicting effective stress relaxation coefficient of polymer matrix composite

Abstract

The invention provides a method for predicting the effective stress relaxation coefficient of a polymer matrix composite.The method includes the steps that firstly, a linear viscoelatic material constitutive equation in a time intra-domain integral form is established based on the Boltzmann superposition principle; then the effective stress relaxation rigidity of the polymer matrix composite formed by periodic unit cells is defined; then a mesomechanics model for solving an effective stress relaxation rigidity matrix of the polymer matrix composite is established based on the variation asymptotic homogenization theory; finally the effective stress relaxation rigidity of the polymer matrix composite is predicted based on the established mesomechanics model.According to the method, attributes of different materials in different directions can be obtained in the one-time solving process, and compared with a method in which rerunning is conducted under different loading conditions, the method is simpler, more convenient, more efficient and rapider.The calculated effective stress relaxation coefficient is consistent with the precision of a wave function, no more approximation relations need to be introduced, calculation precision is higher, and the strength and service life of the polymer matrix composite are predicted more accurately.

Description

technical field [0001] The invention relates to the field of material mechanical performance analysis, in particular to a method for predicting the effective stress relaxation coefficient of polymer-based composite materials. Background technique [0002] Polymer-based composites are mainly composed of various long and short fibers embedded in an organic polymer matrix. They have excellent properties that cannot be taken into account with a single material, and their application proportions in main load-bearing structures such as aircraft fuselages and wings continue to increase. Due to the viscoelastic properties of the polymer matrix, polymer matrix composites usually also exhibit significant viscoelastic behavior, that is, the magnitude of stress and strain varies with time and temperature. The viscoelastic phenomenon of polymer matrix composites originates from the long molecular chains of the polymer matrix. Viscoelasticity-induced creep and stress relaxation limit the...

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Problems solved by technology

[0005] In view of the above-mentioned deficiencies in the prior art, the patent of the present invention provides an efficient and reliable prediction method for the effective stress relaxation coefficient of polymer-based composite materials, which solves the problems of low analysis efficiency and poor precision in the prior art, especially overcomes the Defects of Insufficient Prediction Accuracy of Effective Stress Relaxation Stiffness

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