The caustic method is applied to compressive shear experiment and used to detect the stress intensity factors of cracks prefabricated on plexiglass sample. Loading, friction of crack planes and influence among cracks ...The caustic method is applied to compressive shear experiment and used to detect the stress intensity factors of cracks prefabricated on plexiglass sample. Loading, friction of crack planes and influence among cracks are not needed to know as they are combined and transformed into the caustic shadow used in detecting the stress intensity factor. Even boundary condition is not necessary. Therefore it is effective to determine the stress intensity factor of compressive shear crack.展开更多
The stress and deformation fields near the tip of a mode-I dynamic crack steadily propagating in an elastic-perfectly plastic compressible material are considered under plane strain conditions. Within the framework of...The stress and deformation fields near the tip of a mode-I dynamic crack steadily propagating in an elastic-perfectly plastic compressible material are considered under plane strain conditions. Within the framework of infinitesimal displacement gradient theory, the material is characterized by the Von Mises yield criterion and the associated J(2) flow theory of plasticity. Through rigorous mathematical analysis, this paper eliminates the possibilities of elastic unloading and continuous asymptotic fields with singular deformation, and then constructs a fully continuous and bounded asymptotic stress and strain field. It is found that in this solution there exists a parameter phi(0) which cannot be determined by asymptotic analysis but may characterize the effect of the far field. Lastly the variations of continuous stresses, velocities and strains around the crack tip are given numerically for different values of phi(0).展开更多
The cold-work tool steels T10A and GCr15 have been studied with regard to the influence of austenitization temperature, tempering temperature and the residual stress on the crack propagation rate and the critical crac...The cold-work tool steels T10A and GCr15 have been studied with regard to the influence of austenitization temperature, tempering temperature and the residual stress on the crack propagation rate and the critical crack length. The kinds of fracture morphology have been studied too. The crack propagation rate is dependent strongly on the austenitization temperature, the tempering temperature and the surface compressional residual stress in specimens.展开更多
基金The Specialized Funds for National Key Basic Study (G1998040704), the Dual Project of China Earthquake Admini-stration (9691309020301), and National Natural Sciences Foundation of China (46764010).
文摘The caustic method is applied to compressive shear experiment and used to detect the stress intensity factors of cracks prefabricated on plexiglass sample. Loading, friction of crack planes and influence among cracks are not needed to know as they are combined and transformed into the caustic shadow used in detecting the stress intensity factor. Even boundary condition is not necessary. Therefore it is effective to determine the stress intensity factor of compressive shear crack.
基金The present work is supported by the National Natural Science Foundation of China
文摘The stress and deformation fields near the tip of a mode-I dynamic crack steadily propagating in an elastic-perfectly plastic compressible material are considered under plane strain conditions. Within the framework of infinitesimal displacement gradient theory, the material is characterized by the Von Mises yield criterion and the associated J(2) flow theory of plasticity. Through rigorous mathematical analysis, this paper eliminates the possibilities of elastic unloading and continuous asymptotic fields with singular deformation, and then constructs a fully continuous and bounded asymptotic stress and strain field. It is found that in this solution there exists a parameter phi(0) which cannot be determined by asymptotic analysis but may characterize the effect of the far field. Lastly the variations of continuous stresses, velocities and strains around the crack tip are given numerically for different values of phi(0).
文摘The cold-work tool steels T10A and GCr15 have been studied with regard to the influence of austenitization temperature, tempering temperature and the residual stress on the crack propagation rate and the critical crack length. The kinds of fracture morphology have been studied too. The crack propagation rate is dependent strongly on the austenitization temperature, the tempering temperature and the surface compressional residual stress in specimens.
