Study On Micro-Mechanic Behavior Of CelluarMaterial Based On Its Constitutive Characteristics

In the dissertation, the development of the high-temperature self-lubricating material was reviewed, and the application in the lubrication filed was summarized meanwhile, thus the research purpose of the micro-mechanics behavior of cellular structure based on the material's constitutive characteristic was put forward and specified.After investigating the structure characteristic of self-lubricating material, the micro-mechanics behavior was studied based on the fact that the hard and soft phase were composed of homogeneous composites, then the material parameters, including equivalent elastic modulus and thermal expansion coefficient were further analyzed, as well as the effect of constitution of the material on the parameters. To investigate the cellular deformation behavior of the self-lubricating material, a cellular model with micro-pores has been built to analyze the effect of different factors on the cellular deformation, where the factors mainly included porous ratio, temperature at working condition and the volume ratio of each component in hard phase as well as soft phase, then the precipitation volume of the solid lubricant could be obtained.To research the mechanic stability of the material with film on substrate, a cohesive zone (CZ) was introduced to establish the finite element CZ of the material with the structure of solid film/matrix. A bilinear traction separation law was adopted to simulate the stress-strain behavior on the interface.To improve the working stability of the lubricant film, the cohesive zone model was built to study the micro-mechanics of crack on the interface of the film. To further research the factors influencing on the crack length, the effect of load on indenter, the elastic modulus of film and substrate, film thickness and the fracture energy of the cohesive element on the crack length were discussed based on the finite element CZ model.