不同加载速率下混凝土损伤阶段的划分  

Damage stage division of concrete under different loading rates

作　　者：马小亮[1] 彭刚[1] 肖杰[1] 胡伟华[1,2] 

机构地区：[1]三峡大学土木与建筑学院,湖北宜昌443002 [2]十堰市建筑设计研究院,湖北十堰443000

出　　处：《水利水运工程学报》2016年第6期90-96,共7页Hydro-Science and Engineering

基　　金：国家自然科学基金资助项目(51279092)

摘　　要：在不同加载速率(10^(-5)/s,10^(-4)/s,10^(-3)/s,10^(-2)/s)下进行混凝土试块单轴受压试验,基于改进后的Weibull模型构建了损伤变量,并在应变空间下对损伤曲线做了进一步的细化研究。首先根据损伤曲线的特点,提出了合理方法来确定损伤界点在曲线上的位置,两个界点将损伤曲线划分为3个损伤阶段。在此基础上,探讨了加载速率对损伤界点、损伤阶段长度的影响规律。研究结果表明:1第一损伤界点对加载速率的提高较为敏感,并随加载速率的增大几乎呈线性发展,第二损伤界点对加载速率的提高不敏感;2加载速率的提高使3个损伤阶段的区间长度重新分配,对前两个损伤阶段影响较大,对第3个损伤阶段区间长度的影响较小;3两损伤界点位置基本对称分布于峰值应变两侧,大部分损伤集中在峰值应力1倍的峰值应变范围内,且两损伤界点对应的应变水平比值约为3.5,并随加载速率的提高而减小。The tests on the uniaxial compression of concrete specmens have been done under the conditions of different loading rates （10^-5/s,10^-4/s,10^-3/s,10^-2/s） in this study. Based on the improved Weibull model an expression for the damage variables was set up, and the further detailed researches on the damage curves under the strain space were carried out yet. According to the characteristics of the damage curves, the establishment of a reasonable method to determine the positions of the damage critical points on the curves, and then through two damage critical points the curves are divided into three stages. On this basis, the influences of the damage critical points and the length of the stages under the different loading rates were analysed. The test analysis results show that：（1） the first damage critical point is more sensitive to the increase of the loading rates and is almost linear development process with the increase of the loading rates, the second damage critical point is not sensitive to the increase of the loading rates. （2） the increase in the loading rates made the redistribution of the interval length of the three damage stages, which has the greater influences on the first two stages and no influences on the interval length of the third stage. （3） the positions of two damage critical points are symmetrically distributed on the both sides of the peak strain, and the most of the damage is focused within the peak strain about twice as large as the peak stress, and the ratio of the stress level corresponding to two damage critical points is about 3.5 and it decreases with the increase of the loading rates.

关 键 词：混凝土 加载速率 阶段划分 损伤界点 损伤阶段 

分 类 号：TU502.6[建筑科学—建筑技术科学]