骨架非线性含液多孔介质力学行为分析的近场动力学方法

Fluid-saturated porous media exist widely in nature and engineering, and their mechanical behaviors are closely related to the safety assessment of engineering structures, the extraction of mineral and energy, etc. However, the mechanical analyses of these materials usually involve heterogeneities of structures and properties, nonlinear deformations of solid skeletons (such as elasto-plasticity, large deformation, fracture and failure, etc) and coupling behaviors of solid and fluid. These analyses are difficult to be performed by using the conventional mechanics theories and numerical methods (including some finite element methods and meshfree methods) and many challenging problems may be encountered, such as large-scale computing, low computational efficiency, inconvenient description of the fracture behaviors, mesh dependency of the results, etc. To address these problems, based on the nonlocal and multiscale computational approaches, this project aims at the establishment of peridynamic theories and related algorithms for the mechanical analyses of porous media containing fluid, including the elasto-plastic, geometrical nonlinear, fracture and failure analyses, and the coupled peridynamic and extended multiscale finite element method for the mechanical analyses of large-scale engineering problems of fluid-saturated porous media. Moreover, this project will develop effective numerical simulation tools for the mechanical analyses of fluid-saturated porous media involving nonlinear deformation of the solid skeleton. The outcomes of the project will advance the thorough study of theories and methods for related problems.

含液多孔介质在自然界和工程中大量存在，其力学行为分析与工程结构安全性评估和能源开采等密切相关。然而含液多孔介质的力学分析中往往涉及到材料的强非均质特征、骨架的非线性变形行为（弹塑性、大变形乃至断裂破坏等）以及固体骨架与孔隙流体的耦合作用，其分析求解难度大。采用传统有限元和无网格方法进行分析时往往会遇到计算规模大、计算效率不高、断裂行为难以有效描述以及计算结果具有网格依赖性等诸多问题。针对这些问题，本项目将借鉴非局部作用和多尺度计算思想，建立考虑骨架弹塑性、大变形及断裂破坏等非线性变形的含液多孔介质拟静力和动力问题分析的近场动力学理论和方法，发展大规模非均质含液多孔介质非线性力学行为分析的近场动力学—扩展多尺度有限元耦合求解模型和算法，开发适合于骨架非线性大规模非均质含液多孔介质力学行为分析的数值模拟软件，为相关问题基本理论与方法的深入研究打下基础。

含液多孔介质在自然界和工程中大量存在，其力学行为分析与工程结构安全性评估和能源开采等密切相关。然而含液多孔介质的力学分析中往往涉及到材料的强非均质特征、骨架的非线性变形行为（弹塑性、大变形乃至断裂破坏等）以及固体骨架与孔隙流体的耦合作用，其分析求解难度大。采用传统有限元和无网格方法进行分析时往往会遇到计算规模大、计算效率不高、断裂行为难以有效描述等诸多问题。围绕上述问题，本项目开展了骨架非线性含液多孔介质力学行为分析的近场动力学方法研究。针对多孔介质物理力学性质的强非均质性特征以及含液介质内部固体和液体的耦合作用，借鉴非局部作用和多尺度计算思想，建立了考虑骨架弹塑性、大变形及断裂破坏等非线性变形的含液多孔介质拟静力和动力问题分析的近场动力学理论和方法，发展了大规模非均质含液多孔介质非线性力学行为分析的近场动力学—扩展多尺度有限元耦合求解模型和算法。本项目所发展的理论框架和算法体系不仅为一大类多场多相耦合大变形断裂破坏问题的数值分析提供了可供借鉴的理论、方法和求解思路，同时也为工程结构的安全性评估（如山体滑坡、地基沉降等）和能源开发（如天然气、页岩气、地热等地下资源的开采）等提供了有效的分析手段。项目共发表SCI收录期刊论文16篇；培养毕业博士3人、硕士1人；参加国际学术会议5人次，其中在国际学术会议上做邀请/Keynote报告4人次。