颗粒增强复合材料结构损伤演化和破坏的FEM-VCFEM-MD多尺度模拟

Studies on the multiscale for composites are a kind of challenging important multidisciplinary problem, because the phenomenon of multiscale reflects the basic nature of matter world as well as particulate reinforced composites，it has great wealth scientific connotation. The design and development of high performance materials requires a thorough understanding and careful control of microstructure and its effect on properties. This is particularly challenging given the multiphase and heterogeneous nature of most high performance composite materials..Modeling of the behavior of materials can be used as a versatile, efficient and low cost tool for developing an understanding of material behavior. .The object of the project is to propose the new FEM-VCFEM-MD multiscale idea, establish the related model, and explore the coupling mechanism of multiscale, for numerical simulations of damage evolution and fracture in macro-structure of particulate reinforced composites, in which there are microsacle-mesoscale coupling, mesoscale-macroscale coupling. A multiscale method for coupling finite element method and VCFEM model will be achieved based on a multigrid idea. The effect of microstructure damage and fracture on mechanics properties of macro structures, especially the breakdown mechanism of macro structures induced by microstructure fracture, will be explored by FEM-VCFEM multiscale model. A multiscale method for coupling the molecular dynamics model and VCFEM model will be achieved based on a domain decomposition idea, in which, the part of VCFEM model will be refined to a full atomistic description near the crack tips, and an interface condition will be proposed to provide appropriate boundary conditions for the atomistic and continuum models. A new algorithm of self-adaption and remeshing is used to model the initiation and propagation of microstructure cracks, induced by atomistic model, and the crack coalescence process in macro structure..For macrostructures with a large number of randomly distributing inclusions under all kind of complicated loads, the whole process of macrostructure breakdown induced by the MD controlled microstructure fracture, will be simulated in Parallel on high performance computers. Mutilscale simulation models will be verified by some verification experiments.

复合材料的多尺度研究是一项富有挑战性的多学科重要课题。材料的数值模拟是一种便捷、有效和低成本的研究手段。本项目的目标就是为数值模拟颗粒增强复合材料宏观结构的损伤演化和破坏，提出一种新的FEM-VCFEM-MD多尺度耦合的思想，建立相关模型，探讨多尺度的耦合机理。新模型中将包含微观－细观的多尺度耦合和细观－宏观多尺度耦合。基于多重网格的思想，提出一种有限元和VCFEM的耦合模型。基于域分解的思想，提出一种分子动力学和VCFEM耦合的多尺度方法：在裂尖区域完全用原子来描述，在原子模型区域和VCFEM连续介质区域之间建立适当的界面条件。建立相应网格自适应和重划分方法，模拟原子结构破坏诱发的微结构裂纹和进一步贯穿形成的宏观裂纹。在高性能计算机上实现多尺度模拟含大量随机分布夹杂的颗粒增强复合材料宏观结构在各类复杂载荷下的损伤演化和失效破坏全过程，探讨原子结构破坏和微结构损伤诱发宏观结构失效的机理。

针对复合材料的多尺度这一富有挑战性的重要课题，采用数值模拟这种便捷、有效和低成本的研究手段。本项目为数值模拟颗粒增强复合材料宏观结构的损伤演化和破坏，提出了一种新的FEM-VCFEM-MD多尺度耦合的思想，建立了相关模型，探讨了多尺度的耦合机理。新模型中包含微观－细观的多尺度耦合和细观－宏观多尺度耦合。基于多重网格的思想，提出了一种有限元和VCFEM的耦合模型。基于域分解的思想，提出了一种分子动力学和VCFEM耦合的多尺度方法：在裂尖，在原子模型区域和VCFEM连续介质区域之间建立了界面条件。建立了相应网格自适应和重划分方法，模拟原子结构破坏诱发的微结构裂纹和进一步贯穿形成的宏观裂纹。在CPU和GPU异构并行高性能计算机上实现了多尺度模拟含大量随机分布夹杂的颗粒增强复合材料宏观结构在各类复杂载荷下的损伤演化和失效破坏全过程，探讨了原子结构破坏和微结构损伤诱发宏观结构失效的机理。