复合材料DCB试件裂纹扩展理论分析

Theoretical analysis of crack propagation in composite DCB specimens

  • 摘要: 在弹性地基梁模型基础上,通过挠度与相对位移关系引入了双线性cohesive本构关系,并通过界面损伤因子统一描述界面损伤状态,在裂纹尖端考虑了损伤黏聚区存在,分别获得了各段通解。采用连续性边界条件求解积分常数,并以裂纹长度以及黏聚区范围为变量求解获得了载荷-位移曲线,从而获得了双悬臂梁(DCB)试件裂纹扩展过程。通过与已有理论模型结果对比,验证了本文理论分析的正确性,而文中理论考虑了弹性段后非线性的存在,且可同时考察3个cohesive参数的影响。通过研究界面参数变化对载荷-位移曲线的影响,从而对准确模拟界面时cohesive参数的选取提供一定的依据,并分析了界面参数与黏聚区长度的关系。

     

    Abstract: Based on the elastic foundation beam model, the bilinear cohesive constitutive relation was introduced through the relationship between the deflection and the relative displacement, unified description of interface damage state through the interface damage factor was used, and the damage cohesive zone was taken into account in the crack tip and the general solutions of each segment of double cantilever beam(DCB) specimen were found. The integral constant was solved with the continuity boundary conditions, and the load-displacement curve was obtained with of crack length and the cohesive zone range as the variables, thus DCB specimen crack propagation process was obtained. To verify presented theoretical analysis, in which the nonlinear phenomenon after elastic segment and the effect of the three cohesive parameters were considered simultaneously, some comparisons were made with the existing theoretical results. The effect of three interface parameters on the DCB specimen load-displacement curve was investigated, and the results provide the basis for the selection of interface parameters. The relationship between interface parameters and cohesive zone length was given.

     

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