Basic Studies on Dynamic Interfacial Fracture Mechanics

在本研究项目中，采用实验、理论和计算力学相结合的方法对动态界面断裂现象进行了研究。通过这些研究，获得了动态界面断裂力学的基本信息和数据。进一步阐明了非动态界面断裂现象的一些机理。本项目主要研究成果如下：1.研究成果。实验研究：(1)界面断裂韧性和分离能释放率的评价；(2)等效残余力概念和残余应力强度因子评价方法的发展；(3)发现静载荷和冲击载荷作用下界面动态断裂现象裂纹速度的差异；(4)发现界面动态断裂中声速裂纹速度的可能性。理论研究：(1)建立了路径独立分离T*积分、局部独立分离动态J积分、路径独立分离J积分的概念；(2)推导了分离动力J积分与应力强度因子之间的关系；(3)阐明了张力主导型和剪切主导型载荷作用下界面裂纹扩展的能量流机制；(4)阐明了双材料两侧向界面裂纹尖端扩展的断裂能供给机制。计算力学研究：(1)界面裂纹动态扩展的移动有限元方法的发展；(2)跨声速和超声速界面裂纹扩展数值模拟的成功；(3)跨声速和超声速裂纹扩展能量释放率的评估；利用动态J积分，(4)实现裂纹尖端跨声速和超声速传播产生的马赫数激波的可视化，(5)澄清界面裂纹分离能量释放率的冲击响应，(6)基于delaunay自动网格生成的移动有限元方法的发展，(7)基于裂隙路径预测模式的混合相模拟成功实现动态裂隙路径的数值预测，(8)开发应用阶段方案非直线断裂现象的模拟。由于上述研究成果包含了分离动态J积分的概念等许多重要内容，本课题的研究成果有望为动态界面断裂力学的建立做出贡献。少

In this research project, dynamic interfacial fracture phenomena were investigated by using experimental, theoretical and computational mechanics approaches in a unified fashion. Through these investigations, fundamental information and data on dynamic interfacial fracture mechanics were acquired. Furthermore, some mechanisms of -dynamic interfacial fracture phenomena were clarified. The major research results of this project are listed as follows :1. Experimental Studies :(1) Evaluations of interfacial fracture toughness and separated energy release rates,(2) Developments of the concept of equivalent residual force and the evaluation method of residual stress intensity factor,(3) Finding of the differences in crack velocities of interfacial dynamic fracture phenomena under static and impact loads,(4) Finding of the possibility of intersonic crack velocity in dynamic interfacial fracture.2. Theoretical Studies :(1) Creation of the concepts of path independent separated T* integral, pat … More h independent separated dynamic J integral, path independent separated J integral, and separated energy release rate,(2) Derivation of the relations between the separated dynamic J integrals and stress intensity factors,(3) Clarification of the mechanisms of energy flow to propagating interfacial cracks under tension-dominant type and shear-dominant type loads,(4) Clarification of the mechanism of fracture energy supplies to a propagating interfacial crack tip from both sides of bimaterial.3. Computational Mechanics Studies :(1) Developments of moving finite element methods for dynamic interfacial crack propagation,(2) Success of numerical simulations of intersonic and supersonic interfacial crack propagation,(3) Evaluation of energy release rate for intersonically and supersonically propagating cracks, using the dynamic J integral,(4) Visualization of Mach shock waves emanated from intersonically and supersonically propagating crack tips,(5) Clarification of impact responses of separated energy release rates for interfacial cracks,(6) Development of moving finite element method based on delaunay automatic mesh generation,(7) Success of numerical prediction of dynamic fracture path using mixed-phase simulation with fracture path prediction mode,(8) Developments of schemes for application phase simulation of non-straight fracture phenomena.Since the above research results include many important items such as the concept of the separated dynamic J integral, the outcomes of this research project can be expected to contribute to the establishment of dynamic interfacial fracture mechanics. Less