Fatigue life prediction method for composite laminate containing layered damage

Abstract

The invention discloses a fatigue life prediction method for a composite laminate containing layered damage, and the fatigue life prediction method comprises the following steps: (1), carrying out thefatigue test of the composite laminate under different stress ratios, and carrying out the fitting based on the fatigue test data, so as to construct an expression of the modulus of a material alongwith the number of fatigue cycles; (2) establishing a mathematical model based on boundary conditions and layered damage parameters of the composite laminate containing layered damage under a fatigueload working condition; (3) under any cycle number, updating modulus parameters of the material according to an expression between the modulus of the material and the fatigue cycle number; (4) based on a Ritz method, a first-order shear deformation theory and a fracture mechanics method, predicting expansion and residual strength of layered damage in the laminate; and (5) enabling the residual strength of the laminate to be lower than the cycle number of a fatigue load stress peak value for the first time to obtain the fatigue life of the laminate containing the layered damage. According to the fatigue life prediction method, the fatigue life of the composite laminate containing the layered damage is predicted based on a theoretical method, and related parameters are obtained only by performing a fatigue test on a basic performance test piece of the composite material before application, so that the calculation efficiency can be remarkably improved, and the test period is shortened, and the test cost is reduced.

Description

technical field [0001] The invention relates to the field of damage tolerance of composite material laminates, in particular to a method for predicting the fatigue life of composite material laminates with delamination damage. Background technique [0002] Delamination damage is a key damage mode that seriously affects the load-bearing performance of composite materials. Its existence will significantly reduce the integrity of its structure, and it will easily lead to premature buckling and failure of the structure during the service life. At the same time, delamination damage is an internal damage mode of composite laminated structures, which is usually not easy to be detected in actual engineering use, which greatly increases the potential risk of this damage mode to composite material structures. [0003] In the existing research work on composite laminated structures with delamination damage, scholars have devoted themselves to analyzing the influence of delamination dam...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in the present invention is: to overcome the deficiencies of the prior art, to establish a fatigue life prediction method for composite material laminates with delamination damage for the first time based on the Ritz method, first-order shear deformation theory and fracture mechanics method, to realize Prediction of fatigue life of composite laminates with delamination damage, and before application, it is only necessary to perform fatigue tests on composite laminates under different stress ratios to provide input parameters, so the calculation efficiency can be significantly improved and the test cost can be reduced

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