金属裂纹板复合材料胶接修补强度的弹塑性有限元预测

Repair strength predictions of cracked metal plates bonded with composite patches using elastic-plastic finite element method

金属裂纹板经复合材料补片胶接修补后,其结构强度明显提高,但裂纹板中的裂纹会导致严重的应力集中现象,并易产生塑性变形,呈现强烈的材料物理非线性特性,需要采用弹塑性力学原理,进行复合材料胶接修复结构的静强度预测。为此,考虑金属板材料的非线性特性,建立了金属裂纹板复合材料胶接修补结构的弹塑性有限元模型,并通过试验验证了模型的有效性。在此基础上,提出了基于裂纹尖端的张开位移(COD)判据的拉伸强度预测方法,分析了修复结构的塑性应变、COD以及静拉伸强度。结果表明:相对于应力强度因子K判据,COD判据能更有效地预测修复试件的静拉伸强度。

The structure strength of cracked metal plates can be greatly improved with the help of bonded composite patches.However,the existence of crack in cracked plates will lead to serious stress concentration phenomenon and produce plastic deformation easily,which shows strong material physics nonlinear characteristics.It is necessary to use elastic and plastic mechanical principle to predict the static strength of the repaired structure bonded with composite patches.Considering the material nonlinearities of the metal plate materials,the elastic-plastic finite element model of the cracked metal plates bonded with composite patches was established,which was validated by test results.On the basis,a method predicting tensile strength was proposed based on crack opening displacement（COD）theory in crack tip,and the plastic deformation,COD of the repaired structure and static tensile strength were analyzed.Results show that,compared with the stress intensity factor K theory,the COD theory can give more precise result in predicting the static tensile strength of the repaired specimen.