A Strength Prediction Method for Composite Laminates with Uncertain Parameters Based on Final Layer Failure

Abstract

The invention discloses a final layer failure-based strength prediction method for a composite laminated plate with uncertain parameters. The method comprises the steps of (1) obtaining mechanical property distribution characteristic parameters and numeric simulation sample points of a single-layer plate according to a composite material mechanics test; (2) starting a loop, and calculating a stiffness conversion matrix of the single-layer plate by utilizing a stiffness matrix and a ply angle; (3) calculating stretching, coupling and bending stiffness of the laminated plate according to a laminated plate constitution form; (4) calculating a surface strain in the laminated plate and a main stress of the single-layer plate based on a constitutive equation; (5) substituting the main stress into a failure criterion to calculate a strength ratio, and performing performance degradation on a single-layer plate corresponding to a minimum strength ratio; (6) repeating the steps (2) to (5), stopping calculation until the strength ratio is less than 1, and outputting final layer failure strength; and (7) repeating the steps (2) to (6) until the loop is finished so as to obtain a strength distribution range of the laminated plate. According to the method, a final layer failure strength distribution characteristic of the laminated plate with the uncertain parameters can be effectively predicted.

Description

technical field [0001] The present invention relates to the research on the method for predicting the failure strength of the final layer of composite material laminates, in particular to a method for predicting the strength of composite material laminates with uncertain parameters based on the failure of the final layer, considering the uncertainty of the mechanical performance parameters of the laminate and based on The determination of the strength distribution information of the laminate under the failure theory of the final layer, including the upper bound and the lower bound, ensures the correctness and effectiveness of the strength prediction of the composite laminate, and also lays a theoretical foundation for the reliability optimization of the final layer strength of the laminate . Background technique [0002] Composite laminates have the advantages of light weight, high specific strength, and free design, and have been widely used in automobiles, machinery, aeros...

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Problems solved by technology

However, it should be emphasized that the failure analysis of the final layer strength of composite materials does not consider the influence of uncertain mechanical parameters, so the obtained failure strength often cannot fully characterize the strength characteristics of the laminated plate structure, thereby limiting the application range and effectiveness of the laminated plate structure. sex

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