| Research Abstract |
In this research project, fundamental studies were carried out mainly for the following items : (1) development of application-phase simulation methodology for dynamic fracture path prediction, and (2) development of dynamic branching fracture path prediction methodology. These studies were performed by using experimental, theoretical and computational mechanics approaches in a unified fashion. Through these investigations, fundamental information and data on dynamic fracture phenomena were acquired. Furthermore, some mechanisms of dynamic fracture phenomena were clarified. The major research results of this project are listed as follows :
1. Experimental Studies :
(1) Elucidation of the governing condition for dynamic branching fracture
(2) Development of the theory of caustics for transonic interfacial fracture
(3) Developments of various intelligent hybrid measurement methods automatically detecting and eliminating experimental measurement erros
(4) Development of the minimum correlation
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coefficient searching method for full-field measurement image correlation method
(5) elucidation of correlation between the dynamic crack-tip energy flux and fracture surface coarseness
(6) Measurements of the stress singularity field factor and the singularity order for transonically propagating crack tips
2. Theoretical Studies
(1) Derivation of a unified asymptotic solution for dynamic interfacial fracture
(2) Development of the switching method of the path independent dynamic J integral for dynamically branched cracks
(3) Derivation of the dynamic J integral for piezoelectric materials
(4) Derivation of the asymptotic crack tip near field solution for piezoelectric materials
(5) Development of the component separation method for extracting mechanical mixed-mode stress intensity factors and the electric displacement intensity factor.
(6) Derivation of the variational principle for carack growth problems
3. Computational Mechanics Studies :
(1) Developments of various moving finite element methods based on Delaunay automatic mesh generation
(2) Success of numerical path perediction simulations of dynamnic branching fracture
(3) Success of the application-phase simulations of dynamic fracture phenomena under constant crack acceleration
(4) Evaluation of the dynamic J integrals and the stress intensity factors for naturally and dynamically propagating crack fronts
(5) Development of nonlinear dynamic fracture simulation methodology
(6) Development of simulation methodology for transonic interfacial fracture with crack-face contact
(7) Elucidation of the formation mechanism of three-dimensional dynamic fracture front
Since the above research results include many important items, the outcomes of this research project can be expected to contribute to the advancement of dynamic fracture mechanics.
For the present and related achievements, the following awards have been offered.
(1) JSME Materials and Mechanics Achievement Award,
(2) The JSME Award for Best Paper,
(3) JSME Computational Mechanics Achievement Award,
(4) JSMS Impact Division Achievement Award,
(5) SEM Hetenyi Award Less
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