Papers by Author: Yun Hong Cheng

Abstract: By the approaches of complex variable functions, two dynamic propagation problems of mode Ⅲ interface crack were researched. The problems considered can be very facilely changed into Riemann-Hilbert problem by means of self-similar functions, and analytical solutions of the stresses, displacements, dynamic stress intensity factors for the edges of mode Ⅲ symmetrical dynamix interface crack subjected to moving increasing loads Pt2/x2 and Px3/t2, respectively, were obtained by the methods of self-similar functions. After those solutions were utilized by superposition theorem, the solutions of arbitrary complex problems can be readily attained.

Abstract: By means of the built dynamic fracture model of bridging fiber pull-out of composite materials, the problems considered will be transformed into Riemann-Hilbert problem in terms of the theory of complex functions. Analytical solutions of the stresses displacements, dynamic stress intensity factors, strain energy release rate and bridging fibrous fracture speeds under the conditions of an moving increasing loads, Pt/x, Px2/t, respectively, can be facilely obtained by the approaches of self-similar functions. After those solutions were utilized by superposition theorem, the solutions of arbitrary complex problems can be attained.

Abstract: By the approaches of the theory of complex functions, two dynamic propagation problems of symmetrical mode Ⅲ crack were researched. The problems considered can be very facilely changed into Riemann-Hilbert problem by means of self-similar functions, and the general representations of analytical solutions of the stress, the displacement and dynamic stress intensity factor under the conditions of moving variable loads Pt and Px2/t2 which were applied the edges of mode Ⅲ crack, respectively, were readily acquired.

Abstract: After fiber reinforced ceramics occur a crack, their fibrous position form bridging fibers, moreover a crack usually extends in the modality of similarity. In order to analyze facilely problems of fiber reinforced ceramics, bridging fiber segment is substituted for loads. A dynamic model of crack propagation is built and its fracture dynamics problems are researched by the approaches of self-similar functions. When a crack propagates at high speed its fiber continues to break. By application of the theory of complex functions, the problems dealt with can be easily translated into Remann-Hilbert problem. Using the built dynamic model and the ways of self-similar functions, analytical study of the displacements, stresses, dynamic stress intensity factor and bridging fibrous fracture velocity α under the action of a running constant force P and an running increasing load Pt, respectively, can be attained, and it is also utilized to obtain the concrete solution of the model by means of superposition theorem.