建立了Ⅰ型与Ⅱ型失效模式耦合的粘聚单元本构模型,并通过模拟双悬臂梁实验进行了验证。将粘聚单元插入填充区任何2个实体单元之间,预测填充区的随机裂纹,模拟了接头在拉伸载荷下的失效。计算了复合材料基体、界面胶膜、填充物3者不同强度、填充区半径、填充物刚度等多种情况下接头的拉伸失效。计算结果表明:复合材料基体、界面胶膜、填充物3者的强度显著影响接头的承载能力与失效模式;随着填充区半径增大,结构承载能力也随之提高。试验结果验证了模拟结果。
The cohesive zone model(CZM) was employed to simulate the delamination and random crack initiation in composite joints.A bilinear cohesive law incorporating mode Ⅰ,Ⅱ and mixed mode was presented,which was validated by the simulation of double cantilever beam(DCB) test.Cohesive elements were inserted into the space between every two solid elements to predict the random crack initiation in the filler at the root of the composite joint.The composite joint was simulated under pull-off load,and the numerical result is in good agreement with experimental one.In addition,a series of simulation was carried out under different conditions,i.e.different strength of matrix and adhesive,different radius and different filler property.The numerical result shows that the strengths of matrix,adhesive and filler have great influence on the loading capability and the failure modes of the composite joint.The performance of the structure increases with increasing the filler radius.