| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1996: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Research Abstract |
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
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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
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