Unification of thermo-physics of materials and mechanics of concrete structures

在这项研究中，统一的材料和结构的力学和热动力学的同时评估的整体结构和材料性能的混凝土结构的寿命。这项研究的结果可以总结如下。(1)提出了一个集三维有限元、结构分析程序和三维有限元热湿物理分析于一体的计算系统。这种多任务操作下的耦合方法使工程师能够很容易地链接独立开发的计算机代码，即使是编写不同的语言和算法，因为每个系统都由操作系统管理，并且计算结果可以通过公共数据区共享。(2)在上述系统中，应当评估由于水分、水合作用和热传递而引起的胶凝材料的体积变化。在本研究中，我们提出了一个基于微观力学物理的自生干燥收缩模型。收缩行为是由毛细张力和微观孔隙结构的发展来模拟的。该框架可以作为预测混凝土体积变化的一种方法，适用于任意条件下的自生收缩、干燥收缩及其组合。(3)提出了一种基于细观物理信息的混凝土凝固模型，用于预测硬化混凝土的徐变和收缩。骨料被理想化为具有完全弹性的悬浮连续介质，而水泥浆体被视为具有各种力学性能的固化团簇。这两个阶段的组合用于表示早期不稳定瞬态情况下的整体复合材料。在这个框架中，基本蠕变，干燥蠕变，和无约束收缩行为可以在一个统一的方式进行评估，而不区分每一种现象。

In this research, the unification of mechanics and thermo-dynamics of materials and structures is tackled for simultaneous evaluation of the total structural and material performances over the life span of concrete structures. The results of this research can be summarized as follows.(1) An integrated computational system of 3D FE, structural analysis program, and 3D FE thermo-hygro physical analysis was proposed. This coupling method under multi-task operation enables engineers easily to iink independently developed computer codes even if being written different languages and algorithms, since each system is managed by operating system and the calculated results can be shared through the common data area.(2) in the above system, the volume change of cementitious materials due to moisture, hydration, and heat transfer should be evaluated. In this study, we proposed an autogenous and drying shrinkage model based on micro mechanical physics. The shrinkage behavior is modeled from the capillary tension force and the development of micro-pore structure. This framework can be a predictive method of the volume change of concrete due to the autogenous, drying shrinkage and their combination for arbitrary conditions.(3) A solidification model based on microphysical information for the prediction of both creep and shrinkage of hardening young concrete is proposed. Aggregates are idealized as suspended continuum media of perfect elasticity, whereas cement paste is treated as the solidified clusters having each mechanical property. The combination of both phases is used to represent the overall composite under unstable transient situations at early age. In this framework, basic creep, drying creep, and unrestrained shrinkage behavior can be evaluated in a unified manner without distinguishing each phenomena.