Elastoplastic-damage finite-element algorithm of considering elastoplasticity and damage coupling of composite material

Abstract

The invention discloses an elastoplastic-damage finite-element algorithm of considering elastoplasticity and damage coupling of a composite material, and belongs to the field of finite-element analysis of mechanical properties of composite materials. On the basis of a model of carrying out solving of elastoplastic damage of composite materials on the basis of a backward Euler integral rule and Newton iteration, softening influences which are of damage state quantity in a previous incremental step and on current stress are all considered when solving of elastic stress is carried out in initialsolving of trial stress and plastic yielding iteration, thus damage degradation action is considered in an elastoplasticity solving process, and an interaction relationship between plastic behaviors and the damage of the resin matrix composite-material under complex loading conditions is more truly reflected. The algorithm can effectively describe a coupling action relationship between the elastoplasticity and the damage of resin matrix composite-material, and can be applied to the technical fields of scientific research and engineering such as development of elastoplastic-damage constitutive-models of the composite materials in finite-element software, research of mechanical properties of novel resin matrix composite-materials and related refined modeling analysis of engineering structures of the composite materials.

Description

technical field [0001] The invention relates to a finite element analysis technique for mechanical properties of composite materials, in particular to an elastic-plastic damage finite element algorithm considering the coupling of elastic-plasticity and damage of composite materials. Background technique [0002] At present, composite materials have been widely used in many fields such as military equipment, aerospace, civil industry, etc., and composite materials show certain nonlinear mechanical behavior when loaded, and are accompanied by material mechanical properties, structural bearing capacity and service life. of degradation. Therefore, revealing the nonlinear mechanical behavior of composite materials under load and accurately predicting and analyzing the mechanical properties have important scientific research value and engineering significance for the analysis of the load-bearing performance of composite material structures, the optimization design of structural me...

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Problems solved by technology

However, in the finite element algorithm for the prediction of elastic-plastic damage behavior of composite materials, the elastic-plastic stage and the damage degradation stage are mainly considered separately, and the coupling relationship between damage and plasticity in the plastic yield stage is ignored, which is mainly manifested in the algorithm realization. In the process, when the state quantity of the previous incremental step is used to solve the plastic yield state of the current incremental step, the influence of the damage state of the material in the previous incremental step on the current judgment of the yield state and entering the plastic yield stage is not considered, resulting in The ultimate inability to describe the interaction between nonlinear damage and plasticity of resin matrix composites during loading

[0004] Moreover, in the existing commercial large-scale finite element software, there is no model that can be directly provided to users to analyze the elastic-plastic continuous damage behavior of composite materials, all of which require users to write subroutines to realize it, and suitable ones can be used for finite element Algorithms to predict the elastic-plastic continuous damage behavior of composite materials are in short supply, which further increases the difficulty for engineers and technicians to perform finite element analysis on the elastic-plastic damage characteristics of composite structures

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