项目名称： 基于跨尺度随机因素的功能梯度材料热机械断裂力学模型研究

项目编号： No.10872056

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 能源与动力工程

项目作者： 果立成

作者单位： 哈尔滨工业大学

项目金额： 33万元

中文摘要： 功能梯度材料（FGM）断裂理论研究仍限于求解确定的、连续光滑属性的FGM宏观断裂问题，忽略了FGM特有微结构随机物理特征对裂纹尖端场的关键影响。课题力图建立基于跨尺度随机因素的FGM热机械断裂力学模型。利用细观力学单胞模型，引入微结构材料组份体积份数及颗粒分布随机性，获取有效属性。通过求解跨界面斜裂纹的基础问题，使宏观分段指数断裂模型（PE模型）能够涵盖微观结构随机因素的影响。发展了一种高效摄动解法,以求解任意热属性能够体现颗粒微观随机特征情况下的瞬态热传导方程。提出采用摄动解法和PE模型联合求解任意热机械属性FGM断裂问题的思路：用PE模型处理任意机械属性，而用摄动法处理任意热属性。从而有效地实现任意热机械属性FGM中各种复杂裂纹问题的解析求解。最后以适当实验工作来促进模型的完善。建立基于多尺度随机因素的断裂模型，既是领域内的新探索，也是力学向多尺度、更加接近物理本质方向发展的必然要求。

中文关键词： 功能梯度材料；热机械断裂力学模型；跨尺度；随机因素

英文摘要： The theoretical study of functionally graded materials (FGMs) is still limited to solve the macro fracture problmes for FGMs with definite and continuous properties, without considering the key effects of the stochastic physical characteristics of the micro structures in FGMs. This project tries to build the thermomechanical fracture model based on the multi-scale and stochastic factors for FGMs. The effective properties can be obtained by introducing the stochastic component volume percentage and particle distribution in the representative volume element. By solving the fundamental problem for a crack crossing the interface, the effects of the stochastic micro structures can be included in the piecewise-exponential model (PE model). A high-efficiency perturbation method will be developed to solve the transient heat diffusion equation for FGMs with arbitrary thermomechanical properties considering the micro stochastic characteristics of the particles. A new routine is proposed by combining the perturbation method and the PE model: the PE model is used to deal with the general mechanical properties and the perturbation method is used to deal with the general thermal properties. By this routine, the complex crack problems in FGMs with arbitrary thermomechanical properties can be solved effectively. Finally, some experiments will be done to improve the model. To build the fracture model based on multi-scale and stochastic factors is a new investigation in this field and at the same time necessary for fracture mechanics to extend towards the multi-scale and physical nature.

英文关键词： functionally graded material; thermomechanical fracture mechanics model; multi-scale; stochastic factors