可离散有限元法的数值与实验研究

项目名称： 可离散有限元法的数值与实验研究

项目编号： No.10872214

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 徐春晖

作者单位： 中国农业大学

项目金额： 34万元

中文摘要： 在自然界和工程中，存在许多连续体在外力作用下，部分破裂或整体破碎成非连续体（离散体）的现象或实例。目前关于连续体破碎问题在理论和应用方面的研究都还很不成熟。本项目在可离散有限元基本理论、算法和程序研制方面做了较深入研究。 采用精确的有限变形理论和动力学中心差分算法，将有限元法与离散元法的概念有机结合，引入断裂力学和损伤力学的概念建立多重破裂准则实现连续体的逐步破裂与扩展，对自主开发的有限元软件的进行大幅度改造调试，实现从连续体转变为非连续体的复杂物理过程的数值模拟。 本项目主要提出虚拟连接元和节点单元分裂两种不同模型，对脆性及准脆性材料，建立相应的破坏准则；在结构破坏后，引入接触搜索等计算模块；对一些典型问题进行数值模拟，并与实验结果进行分析比较。在模拟连续体破碎问题的理论、算法和软件研制上有一定的创新和进展。 本项目在解决重大工程结构由连续体过渡为非连续体的力学问题时有重要科学意义和广阔的应用前景，为解决工程实际问题提供了新思路和新方向。

中文关键词： 离散元法；有限元法；破裂损伤；岩石力学

英文摘要： The phenomena of the continuum breaking into pieces of non-continuum or disrete bodies under external forces are commonly known in nature and engineering. This kind of studies and applications are not quite maturate yet. The goal of this project is to further study the basic theory, algorithm, and programming of the discretable finite element method. By using the exact finite deformation theory and the central difference method of dynamics, we combined the concepts of finite element method, discrete element method, fracture and damage mechanics to establish the mechanism of multi-fracturing and realize the complete process of deformation - occurring of micro crack - extension of macro crack - fracture of the continuum. We also developed a practical computational software which can numerically simulate the above phenomena effectively. Our project has suggested two kinds of model to simulate the fracture of continuum: first, a kind of virtual joint element, second, nodal split and/or element split. The various types of fracture law of the quasi-brittle material are under studied. Our contact-searching algorithm has successfully simulate several model problems and has compared with known experimental results. It shows that we have new achievement of software designing and new ideas of basic theories in the simulation of multi-fracturing of the continuum. This purpose of this project is to explore the numerical simulation of the complete process of how the continuum breaking into pieces of non-continuum. This will be extremely significant in science and engineering and hopefully future application. We offer our new ideas and new trends in solving practical engineering problems.

英文关键词： DEM;FEM;Fracture and Damage;Rock Mechanics