コンクリートの凍害および凍害－疲労複合劣化シミュレーション

本研究主要针对混凝土结构的冻损问题，以及外加荷载的联合效应，建立一套中尺度分析系统。到目前为止，综合的物理力学模型和数值方法仍然缺乏，这是本研究项目的主要目的。原研究计划已圆满完成。发表两篇纯霜冻损伤物理模型和数值模拟论文；1篇（审稿中）关于冻作用与静荷载联合的建模与模拟；另一个（在书写中）是霜冻效应和疲劳载荷的组合。还发表了几篇会议论文。具体结果如下：(1)建立了计算温度和湿润条件下混凝土材料内部孔隙压力的理论物理模型。(2)基于刚体弹簧模型（RSBM）建立了中尺度模拟模型，利用上述孔隙压力模型可以模拟材料变形。(3)基于多相复合理论，建立了不同冰、液态水和空气掺量下混凝土的有效弹性模量和强度表达式，并用RBSM进行了数值模拟。(4)修正了RBSM在疲劳载荷下的本构模型，并结合内压引起的霜冻损伤。模拟了FTC未损伤和损伤混凝土的S-N曲线。

This research is mainly to develop a mesoscale analyzing system for the frost damage problems of concrete structures, together with the combining effects by external loads. Till now, the comprehensive physical and mechanical model, as well as the numerical method are still absent, which are the main purposes of this research project.The original research plan has been accomplished well. Two journal papers for the physical model and numerical simulation of pure frost damage; one paper (under review) for the modeling and simulation of combined frost action and static loads; another one (under writing) for the combined frost effect with fatigue loading. Several conference papers are also published. The details of outcomes are as follows:(1) The theoretical physical model has been developed to calculate the pore pressures generated inside the concrete material under variation of temperatures and moist conditions. (2) The mesoscale simulation model has been developed based on Rigid Body Spring Model (RSBM), and using the pore pressure model developed above, the material deformation can be simulated. (3) Based on the multi-phase composite theory, the expression of effective elastic modulus and strength of concrete with different amount of ice, liquid water and air is developed and simulated by RBSM. (4) The constitutive model for RBSM under fatigue loading is modified, and combining with frost damage caused by internal pressures. The S-N curve for FTC undamaged and damaged concrete are simulated.