在粘聚元或者粘聚域模型中,能够预测混合失效模式(mixed mode)的粘聚律是通过关联界面的法向分离和切向分离来建立的.考虑完全剪切失效机制的Xu-Needleman粘聚律是目前文献中应用最多的关联粘聚律之一.该文提出粘聚律一致关联准则,采用界面分离功分析法,证明了考虑剪切失效机制的Xu-Needleman粘聚律在混合失效模式下,属于非一致关联粘聚律.理论分析证明,考虑剪切失效的Xu—Needleman粘聚律仅在界面的法向分离功与切向分离功相等的情况下能够正确刻画混合失效模式.基于粘聚律一致关联准则,在考虑剪切失效的Xu—Needleman粘聚律的基础上,进行修正提出一种一致关联粘聚律(CCC).分析证明,这种修正的一致关联粘聚律克服了原有Xu-Needleman粘聚律非一致关联的弊端,能够更好刻画混合失效模式下的破坏行为.
An appropriate coupled cohesive law for predicting mixed mode failure was established by combining normal separation and tangential separation of surface in cohesive zone model and cohesive element method. Xu-Needleman exponential cohesive law with fully shearing failure mechanism was one of the most popular models in literature. Based on the proposed consistently coupled rule/principle, Xu-Needleman law with fully shearing failure mechanism was proved to be a non-consistently coupled cohesive law by analyzing surface separation work. It is shown that Xu-Needleman is only valid in mixed mode fracture when the normal separation work equals to the tangential separation one. Based on the consistently coupled principle and the modification of Xu-Needleman law, a consistently coupled cohesive ( CCC law) was given. It is shown that the proposed CCC law has already overcome the non-consistency defect of Xu-Needieman Law with great promise in mixed mode analysis.