Study on Macro-Meso Coupled Problems in Material Failure

这项研究的第一个目的是制定一项技术，该技术与细观尺度的计算力学有关，可以处理具有结构的材料的断裂行为。本文将基于计算离散连续力学模型的单相固体三维细观分析算法推广到含纤维或夹杂物的多相材料，并考虑了晶内、晶间断裂和相变塑性。第二个目的是掌握其细观结构/行为对本构方程和断裂韧性等宏观性质的影响，并在此基础上评价和改进均匀化方法和损伤力学等宏观模拟。1997年，首先，我们以单相固体（脆性多晶固体）为例，建立了考虑晶内和晶间断裂的三维细观分析算法， ...更多信息 有结构的ial。其次，针对含有微夹杂物的两相固体，建立了考虑晶内、晶间断裂和第二相粒子相变塑性等因素的三维细观分析算法。在1998年，首先，在细观尺度上分析了单相固体和两相固体预先伴随微裂纹损伤时的宏观弹性常数计算，对现有的均匀化方法等给出的理论解进行了评价和改进。从细观尺度分析了单相固体和两相固体中的非平稳损伤发展，对现有的宏观连续介质损伤力学模型进行了评价和改进。最后，对单相和两相固体的裂纹扩展阻力曲线（R曲线）行为进行了细观分析，考虑了细观结构与宏观断裂韧性之间的关系。主持研究者主要负责三维细观分析算法的制定，辅助研究者主要负责编程和数值计算。建立了材料断裂宏细观相互作用问题的计算力学方法。对固体的损伤和断裂现象有了一定的认识。少

This study had the first purpose of formulation of a technique having to do with computational mechanics at a meso-scale which can handle inclusively the fracture behavior of the material which has structure. The three-dimensional meso-analysis algorithm for single-phase solids by using computational disctontinuun mechanics model has been extended to deal with multi-phase materials containing fibers or inclusions and to consider in-and inter-granular fracture and transformation plasticity. It was the second purpose to grasp the influence which their meso-scale structure/behavior exert on the macro property such as constitutive equations and fracture toughness and to evaluate and improve the macro-scale modeling such as the homogenization method and the damage mechanics, based on the results.In 1997, first, we formulated the 3-dimensional meso-analysis algorithm considering in-and inter-granular fracture for single-phase solids (brittle polycrystalline solids) as an example of the mater … More ial which has structure. Next, we constructed the three-dimensional meso-analysis algorithm considering in-and inter-granular fracture and the transformation plasticity of the second-phase particles and so on for two-phase solids which contain microinclusions. Moreover, we made numerical simulations using these and considered about the validity of the computational technique.In 1998, first, analyzing at a meso-scale about the macro elasticity constants computation when single-phase solids and two-phase solids are beforehand accompanied by the microcrack damage, we evaluated and improved theoretical solutions given by the existing homogenization method and so on. Next, analyzing at an meso-scale about the nonstationary damage development in single-phase solids and two-phase solids, we evaluated and improved the existing macro continuum damage mechanics model. Lastly, conducting meso-analysis about the R curve (the crack developing resistance curve) behavior of single-phase solids and two-phase solids, we considered about the relation between the meso-scale structure and macro fracture toughness. The head investigator mainly took charge of the formulation of meso-analysis algorithm of three-dimensions and the assisting investigator mainly took charge of programming and the numerical computation. We established a method of the approach having to do with computational mechanics about the macro-meso interaction problem in case of material fracture. We got some knowledge about the phenomenon of the damage and the fracture of the solid. Less