Study on Macro-Meso Coupled Problems in Material Failure

这项研究的第一个目的是在细观尺度上提出一种与计算力学有关的技术，该技术可以处理具有结构的材料的断裂行为。采用计算圆盘力学模型的单相固体三维细观分析算法已扩展到处理含纤维或夹杂物的多相材料，并考虑晶内和晶间断裂和相变塑性。第二个目的是掌握它们的细观结构/行为对本构方程和断裂韧性等宏观性质的影响，并在此基础上评估和改进诸如均匀化方法和损伤力学等宏观尺度模拟。1997年，我们首先建立了考虑单相固体(脆性多晶固体)晶内和晶间断裂的三维细观分析算法，并以Matter…为例更多的是有结构的al。其次，针对含微夹杂物的两相固体，建立了考虑晶内和晶间断裂、第二相颗粒相变塑性等因素的三维细观分析算法。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宏观弹性常数的计算，对现有的均匀化方法等给出的理论解进行了评价和改进。其次，在细观尺度上分析了单相固体和两相固体中非定常损伤的发展，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R曲线(裂纹扩展阻力曲线)行为进行了细观分析，考虑了细观结构与宏观断裂韧性的关系。首席研究员主要负责三维细观分析算法的制定，辅助研究员主要负责编程和数值计算。我们建立了一种与计算力学有关的方法来处理材料断裂情况下的宏细观相互作用问题。我们对固体的损伤和断裂现象有了一些了解。较少

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