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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 structural strength of the cracked metal plate after being repaired by the patch of composite material is obviously improved. However, the crack in the cracked plate can cause serious stress concentration and is prone to plastic deformation, presenting strong physical nonlinearity of the material and needs to be adopted Elastic-plastic mechanics principle, the static strength of the composite adhesive bonding repair structure is predicted. Therefore, considering the non-linear characteristics of sheet metal, an elasto-plastic finite element model of bonded repaired structure of metal crack plate composite was established. The validity of the model was verified through experiments. On this basis, the prediction method of tensile strength based on crack tip displacement (COD) criterion is put forward. The plastic strain, COD and static tensile strength of the repaired structure are analyzed. The results show that the COD criterion can predict the static tensile strength of the repaired specimen more effectively than the K stress criterion.