论文部分内容阅读
利用MTS Landmark伺服加载试验对砂岩开展循环点荷载试验并对其力学特性进行研究。试验包含恒幅循环加载和荷载逐渐增加的多级循环加载两种方式,其加载频率和下限荷载比的变化范围分别为0.1~5 Hz和0~0.60。分析加载频率和下限荷载比对红砂岩疲劳寿命和滞回特性的影响。结果显示:红砂岩疲劳寿命随加载频率和下限荷载比的增加呈现先减后增的变化规律;在相同循环次数下,滞回环间距随加载频率的增大和下限荷载比的减小而不断增加。同时,红砂岩在循环点荷载作用下仍存在“锻炼”和“记忆”效应。
The MTS Landmark servo loading test was used to carry out the cyclic loading tests on sandstone and its mechanical properties were studied. The tests consist of cyclic loading with constant amplitude and multi-level cyclic loading with gradually increasing load. The changing range of loading frequency and lower limit load ratio are 0.1 ~ 5 Hz and 0 ~ 0.60 respectively. The influence of loading frequency and lower load ratio on the fatigue life and hysteresis of red sandstone was analyzed. The results show that the fatigue life of red sandstone decreases with the increase of the loading frequency and the lower load ratio, and the variation of the decrease of the hysteresis loop increases with the increase of the loading frequency and the decrease of the lower load ratio at the same cycle number. At the same time, red sandstone still has “exercise” and “memory” effects under the cyclic loading.