Papers by Keyword: Fiber Reinforced Ceramic

Abstract: The prediction of fiber reinforced ceramic is one of the most important procedure when investigating the application of ceramic composite. Numerical simulations were applied and a novel model was brought out in this paper. Firstly, four different models for predicting thermal conductivities of unidirectional fiber reinforced materials were compared, which include the Rayleigh,LN,ST and TE model,. It shows that Rayleigh model and LN model have good precision only in low fiber volume content cases. There existed big differences between the experimental and numerical results if predicted the high fiber volume content with either these four models. Then a novel model based on LN model was studied with the correction of the representative volume element method. Further comparison results indicate that the error can be reduced as 55.6% with this novel model. At the same time, the longitudinal (k₁₁) and transverse (k₂₂) thermal conductivities predicted by the novel model were also analyzed. It was found that k₁₁ had a linear relationship with fiber volume fraction and thermal conductivity ratio (p). But k₂₂ had a nonlinear relationship with fiber volume fraction, which increased much greatly when fiber volume fraction increasing at high fiber volume fraction and p>1.

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.