摘要
借助声发射技术对水泥混凝土及橡胶水泥混凝土的疲劳过程进行实时监测,通过声发射信号的强度和活度等相关参数分析疲劳损伤过程.实验结果表明:疲劳循环加载过程中,0.6,0.7,0.8应力水平下水泥混凝土中声发射信号的撞击总数随时间变化均呈现近似线性增长趋势,幅度随时间变化分布密集,声发射信号连续发生,表明水泥混凝土的疲劳损伤过程是一个持续的损伤累计增长的过程;橡胶混凝土声发射信号的撞击总数随时间变化曲线分为中间阶段曲线平缓、幅度随时间变化分布松散3个阶段,疲劳损伤全过程呈现典型的裂纹引发、稳定扩展和失稳扩展3个阶段.由于在疲劳循环加载过程中橡胶的能量耗散特性以及良好的吸声性能,橡胶混凝土中声发射信号发生的强度和活度普遍低于同应力水平下的普通水泥混凝土,损伤演化速度缓慢,损伤程度降低,因此具有优异的疲劳性能.
An acoustic emission （AE） technique is used to monitor the fatigue process of common cement concrete and rubberized cement concrete. The fatigue damage process is analyzed through AE parameters of activity and intensity. The experimental results show that, at each stress level, the accumulative hits of common cement concrete rise almost linearly with loading time under cyclic loading, and AE signals are continuous during the whole fatigue process, which demonstrates the continuous damage accumulation inside common cement concrete. However, the accumulative hits of rubberized cement concrete develop in a different manner. The curves of AE parameters are characterized by three typical damage stages, i.e. , initiation of cracks, stable propagation and unstable propagation of cracks. At the stable propagation stage, the distribution of AE signals with loading time is loose. Due to the energy dissipation effect and the acoustic adsorption of elastic rubber particles, both the activity and intensity of AE signals in rubberized cement concrete are lower than in common cement concrete, therefore less damage is detected and better fatigue performance is achieved in rubberized cement concrete.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2009年第3期574-579,共6页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(50778039)
江苏省自然科学基金资助项目(BK2007111)
关键词
橡胶混凝土
声发射
疲劳损伤
rubberized cement concrete
acoustic emission
fatigue damage
