Damage Prediction for Concrete With and Without Fibre Reinforcement

虽然混凝土结构在设计寿命期间受到大量荷载作用，通常涉及应力逆转，并且已知混凝土在这种反复荷载作用下强度和刚度都会恶化，但对其疲劳行为，特别是低周疲劳范围内的损伤积累知之甚少。为了填补这一知识空白，我们提出了一个全面的试验测试方案，通过测量混凝土在单轴和双轴应力循环下加纤维和不加纤维的耗散能力。本实验研究的结果将构成一个数据库，该数据库将允许开发损伤预测工具和混凝土构件在任意荷载历史下的低周疲劳分析。提出的研究还包括一个分析部分，目的是发展一种理论来模拟混凝土中的损伤积累，并预测变振幅荷载历史的疲劳寿命。由于已知Palmgren-Miner线性损伤累积假设既不适用于金属结构，也不适用于混凝土，因此需要将获得的实验数据作为基础，构建更准确的损伤预测模型，从而确定混凝土材料的剩余寿命。

Although concrete structures are subject to large numbers of load applications during the design lives, often involving stress reversals, and concrete is known to deteriorate both in strength and stiffness under such repeated load applications, relatively little is known about its fatigue behavior, especially about the damage accumulation in the low-cycle fatigue range. It is proposed to perform a comprehensive experimental test program to fill this gap in knowledge, by measuring the energy dissipation capacity of concrete with and without fibre reinforcement under uni-and biaxial stress cycles. The results of this experimental study will constitute a data base that will permit the development of damage prediction tools and low-cycle fatigue analysis of concrete members subjected to arbitrary load histories. The proposed research contains also an analytical component with the objective of developing a theory to simulate damage accumulation in concrete and to predict the fatigue life for variable-amplitude load histories. As the Palmgren-Miner hypothesis of linear damage accumulation is known to apply neither to metal structures nor to concrete, the experimental data to be obtained shall serve as a basis to construct a more accurate damage prediction model with which the remaining life of concrete material can be determined.