盐岩间隔疲劳的声发射特性试验研究

发布时间：2018-01-07 07:22

本文关键词：盐岩间隔疲劳的声发射特性试验研究　出处：《中南大学学报(自然科学版)》2017年07期 　论文类型：期刊论文

【摘要】：为研究时间间隔作用下盐岩疲劳试验的声发射特征,进一步揭示时间间隔对盐岩残余应变及疲劳寿命的影响,利用多功能盐岩试验机和声发射设备对时间间隔作用下的疲劳损伤及声发射特征进行试验研究,将声发射参数与损伤演化、晶体位错相联系,阐述时间间隔对疲劳力学行为的影响机理。结合损伤演化理论建立基于声发射振铃数的累积损伤变量与时间间隔之间的定性关系。研究结果表明:时间间隔的插入会加速疲劳过程中塑性变形的积累,时间间隔越长,塑性变形积累越快,疲劳寿命随之显著降低;时间间隔后循环内声发射振铃数比时间间隔前的多,经过一定时间的无应力静置,后续循环内的声发射变得更为活跃,且时间间隔越长,此现象越明显;在时间间隔内,残余应力参与并主导了细观尺度上盐岩内部结构的调整,由Bauschinger效应导致的反向软化使盐岩结构更为松散,加速塑性变形的积累。时间间隔对疲劳损伤有加速效应。
[Abstract]:In order to study the acoustic emission characteristics of salt rock fatigue test under the action of time interval, the influence of time interval on residual strain and fatigue life of salt rock is further revealed. The fatigue damage and acoustic emission characteristics under the action of time interval were studied by using multi-function salt rock testing machine and acoustic emission equipment. The acoustic emission parameters were associated with damage evolution and crystal dislocation. The influence mechanism of time interval on fatigue mechanical behavior is expounded, and the qualitative relationship between cumulative damage variables based on acoustic emission ringing number and time interval is established based on damage evolution theory. The results show that:. The insertion of time intervals accelerates the accumulation of plastic deformation during fatigue. The longer the time interval, the faster the accumulation of plastic deformation and the lower the fatigue life. After the time interval, the number of acoustic emission rings in the cycle is more than that before the time interval. After a certain time of non-stress setting, the acoustic emission in the follow-up cycle becomes more active, and the longer the time interval, the more obvious this phenomenon is. In the time interval, residual stress participates in and dominates the adjustment of the internal structure of the salt rock on the meso-scale, and the reverse softening caused by the Bauschinger effect makes the structure of the salt rock more loose. Accelerate the accumulation of plastic deformation. The time interval has an accelerated effect on fatigue damage.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点试验室;重庆市勘测院;中国科学院岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金资助项目(51604044,41672292,51574048) 中央高校基本科研业务费专项基金资助项目(106112016CDJZR245518)~~
【分类号】：TU45
【正文快照】： 现实中的地下工程具有极复杂的受力状态,在盐岩地下储气库的运行过程中,周期性注、采气并非连续循环过程,期间存在长短不一的时间间隔。与普通岩石不同,盐岩具有损伤自愈合的优点,其显著的流变特性[1-4]决定了时间间隔势必会影响疲劳过程中的力学行为。自1963年GOODMAN[5]发现

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