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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 concrete specimens were uniaxially pressed under different loading rates (10 -5 / s, 10 -4 / s, 10 -3 / s, 10 -2 / s) Based on the improved Weibull model, the damage variables were constructed and the damage curves were further refined in strain space. Firstly, according to the characteristics of the damage curve, a reasonable method is proposed to determine the location of the damage point on the curve. The two boundary points divide the damage curve into three damage phases. On this basis, the influence of loading rate on the damage point and the length of damage stage was discussed. The results show that the first damage point is sensitive to the increase of loading rate and almost linear with the increase of loading rate, while the second damage point is insensitive to the increase of loading rate. 2 The increase of loading rate makes 3 The length of redistribution of each damage phase has a greater impact on the first two damage phases but less on the length of the third damage phase. The locations of the three damage points are basically symmetrically distributed on both sides of the peak strain, with most of the damage It is concentrated in the peak strain of 1 times of the peak stress, and the corresponding strain level ratio of the two damage points is about 3.5, and decreases with the increase of the loading rate.