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Autori: Nishioka, T., Stan, F., and Fujimoto, T.
Editorial: JSME International Journal, Series A, Special issue on Strength and Fracture, and Experimental Mechanics, Vol. 45(4), p.523-537, 2002.
To the best of the authors’ knowledge, any fracture parameter such as the dynamic J integral for a naturally and dynamically propagating crack front has not been evaluated. In our previous experimental study, high-speed photographs of dynamically propagating crack fronts in DCB specimens were firstly recorded. In this paper, first, to overcome difficulties in three-dimensional dynamic fracture simulation, a three-dimensional moving finite element method together with an automatic element control method is developed using a mapping technique. Next, to make it possible to evaluate the dynamic J integral along the dynamically propagating curved crack front, an equivalent domain integral method of the dynamic J integral is developed. Furthermore, to accurately evaluate dynamic stress intensity factors along the curved crack front, the component separation method of the dynamic J integral is also developed. Based on these simulation technologies, the generation-phase simulations are carried out, using the experimentally recorded histories of three-dimensional dynamic fracture events in 20mm thick DCB specimens. The distributions of the dynamic J integral and stress intensity factor along the actual dynamic fracture fronts are firstly elucidated. Based on these results, pertinent mechanism of three-dimensional fracture is also discussed.
Cuvinte cheie: Fracture Mechanics, Stress Intensity Factor, Crack Propagation, Crack Arrest, Double Cantilever Beam Specimen, High-Speed Photography, Generation-phase Simulation, Dynamic J Integral, Dynamic Energy Release Rate, Three-Dimensional Moving Finite Element Method