基于界面断裂的粘聚区长度计算方法研究

基于各向异性双材料界面断裂力学理论,再根据D-B模型假设的有限裂纹尖端奇异性将消失,推导出复合材料分层裂纹尖端粘聚区长度的计算模型。结果显示复合材料分层裂纹尖端粘聚区具有振荡性(当振荡因子0时),并且粘聚区长度与裂纹长度、应力值及振荡因子有关。将新模型应用于界面单元法中,模拟了双悬臂梁(DCB)和混合型弯曲梁(MBB)分层扩展过程中的载荷-位移关系,并比较了不同的粘聚区长度对收敛性和计算精度的影响,结果表明该模型可较精确地计算复合材料的粘聚区长度,以此为基础划分网格能同时保证收敛性和计算精度要求,并可有效地节省运算时间。

STUDY ON COMPUTATIONAL METHOD FOR COHESIVE ZONE LENGTH BASED ON INTERFACE FRACTURE

Based on interface fracture mechanics for anisotropic bimaterials and D-B model assumption about the singularity disappearing on a finite crack tip,a new computational model for cohesive zone length is derived.The result shows that the delamination crack tip of composite materials exists the oscillation characteristic(When oscillation factor 0),and the cohesive zone length is related on the crack length,stress value and oscillation factor.The new model is applied to the interface element method,and simulating the loading-displacement curves for the delamination growth of a Double-Cantilever Beam(DCB)and Mixed-Mode Bending(MBB),and simultaneously,the comparison is made for convergence characteristics and computation precision through using different cohesive zone lengths.The results show that the model can more accurately compute the cohesive zone length.The convergence and required precision can be simultaneously meted and effectively save operation time through using this model to discrete interface elements.