复合材料T型接头拉伸断裂行为的数值模拟

针对碳纤维复合材料T型接头在拉伸载荷下的断裂行为及其失效强度进行了数值预测,并将预测结果与试验数据进行了对比分析.在该数值模型中,分别使用增强有限单元法和内聚力模型考虑了T型接头三角区填充材料裂纹和层间界面分层的萌生与传播过程.结果表明,数值计算结果与试验结果对比较好,三角填充区域是T型接头结构中裂纹最先萌生的位置;填充材料的断裂行为并不影响T型接头最终失效载荷;加强筋层合板与蒙皮层合板间的分层行为是T型接头拉伸失效的根本原因.

Numerical Simulation of Tensile Fracture Behavior of Composite T-Joint

The fracture behavior and failure strength of carbon fiber composite T-joint under tensile condition were predicted numerically, and the predicted results were compared with the test data. In the numerical model, the initiation and propagation of the filler cracks and interlayer interface stratification in the T-joint triangle region were considered by using the augmented finite element method (AFEM) and the cohesive zone model respectively. The results show that the numerical results are in good agreement with the experimental results, and it can be found that the crack initiates in the triangle region of the T-joint structure. The fracture behavior of the filler does not affect the ultimate failure load of the T-joint. The delamination behavior between stiffened laminates and skin laminates is responsible for the final failure of the T-joints.