中文摘要：

采用声发射技术对混凝土试件在变幅循环轴拉荷载作用下的损伤破坏过程所伴生的声发射信号进行采集，分析混凝土的凯塞效应及典型声发射特性。结果表明：声发射凯塞效应和费利希蒂效应过渡的加载阶段约有62％极限应力，此临界点可作为混凝土轴拉裂缝发展稳定与否的标志；声发射振铃数、声发射ASL平均值和声发射幅度均呈现出随着加载阶段的延续而增加的趋势。相关结果可以作为预测混凝土结构安全和损伤程度的依据。

英文摘要：

Acoustic emission （ AE ） signals associated with the damage processes of concrete specimens under variable amplitude cyclic tension loading were obtained using acoustic emission techniques .The Kaiser effect and typical AE characteristics of the concrete damage processes were analyzed .The results show that the conversion loading stage between the Kaiser effect and Felicity effect was at 62%ultimate stress;this critical point can be used as a sign of a critical state for concrete micro-cracks under uniaxial tension during the stable or unstable development .The AE count number , the average ASL voltage , and the AE amplitude all showed an increasing trend with the extension of the loading stage .The research results can provide a basis for prediction of the structural safety and damage degree of concrete .