摘要
针对目前只有少量成熟的方法可用于评估混凝土的损伤破坏,并对结构的状态不能及时做出判断,本文提出用声发射技术来监测它的损伤演化.根据所得的声发射特征参数时间序列分形理论研究了它的损伤演化过程和破坏程度,得出了水泥砂浆破坏全过程各个应力水平声发射分形特征以及分形维值随实验时间的变化规律.其结果表明:在加载初中期,分形维数忽大忽小,在临近破坏时,分形维数出现"最小-最大"变化模式,利用此模式可为水泥砂浆临界损伤破坏提供一个新的判据.
Only a few mature techniques can estimate the mechanical damage of concrete,but they cannot offer a real - time judgement for structural state, acoustic emission （AE） technology was presented to monitor its damage evolution under three point bending testing. The cement mortar damage evolution law was studied applying the AE characteristic parameter time series fractal theory. The acoustic emission fractal features of all stress levels in the whole cement mortar failure and the changing rules of fractal value were studied. The results show that, in the initial and middle stage of loading, the fractal value of cement mortar is unsteady;When the cement mortar crack begins its fast propagation, the fractal dimension appears the ＂increase - decrease＂ pattern, which can be used to identify the cement mortar critical failure.
出处
《动力学与控制学报》
2008年第3期275-277,共3页
Journal of Dynamics and Control
关键词
声发射
水泥砂浆
分形模型
临界断裂
acoustic emission, cement mortar, fractal modal, critical failure
