Papers by Author: Guo Hui Zhong

Abstract: Based on the microstructure of fiber eutectics and transformation particles composite ceramic, the bridging stress of the fiber eutectic is determined. The bridging load that makes crack closure to reduce the stress concentration of crack tip is calculated. The energy dissipative value of the bridging load is obtained by considering the random orientation of the fiber eutectic. Finally, according to the relationship of the fracture toughness and energy dissipation, the bridging toughening mechanism is established. Analysis shows that the bridging toughening value is enhanced with the increasing of volume fraction and fracture strength of fiber eutectic, and enhanced with the decreasing of interface bonding strength and length-diameter ratio.

Abstract: Laminated composites are the effective ways to toughen Al2O3 ceramics at present. The destruction process analysis of laminated ceramic composite is studied in this paper taking the Al2O3/ZrO2 ceramic composite as the example through the APDL programming. The micro model is established in ANSYS. And the failure stresses of each ply of the ceramic can be calculated by micromechanics method. Then the calculated failure stresses are compared to the simulated failure stresses. The micro model can visualize the destruction process of laminated ceramic composite. The failure criteria of composite material can be self-defining in ANSYS by using APDL. Some ideas of ANSYS application on composite material are given in this paper.

Abstract: Many material have different stress-strain relation in tension and compression, generally the relation is nonlinear. In this paper, we use two exponential functions to approximately represent the stress-strain relation of nonlinearly elastic material and analyze strength-difference structure of bars jointed to Rigid-body of fixed-point motion. The displacement method is used to derive the universal expression of calculating stress and strain. The nonlinear equations for computing angular displacement of the rigid-body has been given and general computing program has been worked out. They can be accurately and conveniently calculated. This problem has been solved satisfactorily.

Abstract: The four-phase model is used to predict the strength of particles in composite ceramic with partial debonding interphase. Firstly the external strain of three-phase cell is determined. Based on the disturbance strain tensor of three-phase cell, the micromechanical stress field of the particle is obtained. Then based on the generalized thermodynamic force of the particle in damage process, the damage equivalent stress of the particle in the three-phase cell can be calculated. As the damage equivalent stress is equal to the ultimate stress of the particle, the micromechanical strength of particles in composite ceramic with partial debonding interphase is obtained. Finally, For Al2O3-ZrO2 composite ceramic with partial debonding interphase, the variations of the micromechanical strength of particles for different orientation angle and different particle diameter are analyzed. The result shows that the micromechanical strength of particles is determined by the 50° orientation three phase cell, and has obvious size dependence. The micromechanical strength of particle will decrease when the particle diameter increase.