Study on the asynchronous phenomenon of the stress rate and strain rate under cyclic loading and unloading tests
LIU Jie1,2,YAN Lizhou2,LI JIanlin1,2,YUAN Tengfei2,YU Zhenmin2,WANG Fei2
(1. Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University Yichang,Hubei 443002,China;2. College of Civil Engineering and Architecture,China Three Gorges University,Yichang,
Hubei 443002,China)
Abstract:In order to study the deformation of rock under cyclic loading and unloading,the tests to the 56 sandstone samples from Three Gorges Reservoir area were carried out. The concept of stress-strain hysteresis was modified according to the asynchronous phenomenon from the tests. The phenomena that the stress is ahead of or behind the strain exist at the same time,so it is more reasonable that the hysteresis phenomenon of stress-strain is named as the stress-strain asynchronous phenomenon. On the basis of the stress-strain asynchronous phenomenon,the asynchronous phenomenon of the stress rate-strain rate should be considered. After the analysis of the asynchronous mechanism of the cyclic loading and unloading test,four concepts,the stress-strain attraction point,the stress rate-strain rate attraction point,the stress-strain compensation mechanism and the stress rate-strain rate compensation mechanism,were proposed. Three findings were obtained. The stress-strain and stress-strain rate synchronization did not occur simultaneously. The asynchronous phenomenon is inevitable and synchronous phenomenon only exists at a certain point. The relationship of stress-strain is the process of spiral cycle progression. The asynchronous phenomenon of the stress rate-strain rate was found for the first time in the cyclic loading and unloading tests and the definition of three asynchronous stages was proposed. The predicted and actual deformation rate,the apparent elastic modulus and the instantaneous Poisson ratio of the samples with the time were analyzed and three methods were put forward to judge the asynchronous stages quantitatively. Besides,by analyzing the mechanism of stress-strain rate based on the same frequency and different peak strength tests,a conclusion is reached that the of the sample and the coincidence degree of increases with the increase of the peak intensity.
刘 杰1,2,颜溧洲2,李建林1,2,苑腾飞2,于振民2,王 飞2. 循环荷载作用下应力速率与应变速率不同步研究[J]. 岩石力学与工程学报, 2017, 36(1): 29-42.
LIU Jie1,2,YAN Lizhou2,LI JIanlin1,2,YUAN Tengfei2,YU Zhenmin2,WANG Fei2. Study on the asynchronous phenomenon of the stress rate and strain rate under cyclic loading and unloading tests. , 2017, 36(1): 29-42.
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