基于小波变换的混凝土压缩损伤模式识别

发布时间：2018-01-27 16:29

本文关键词： 固体力学混凝土声发射小波变换损伤机制　出处：《兵工学报》2017年09期 　论文类型：期刊论文

【摘要】：为了实时获取混凝土中微裂纹扩展演化的物理信息,对实验采集的每一个声发射信号作小波变换,识别出3种典型模式的声发射信号;根据声发射信号的事件密度变化规律和脆性材料断裂理论,将混凝土压缩破坏过程分为微孔洞压缩闭合、裂纹萌生、裂纹生长和裂纹汇合4个阶段。根据混凝土材料中声发射信号频率与裂纹源尺寸呈反比例关系以及声发射信号在4个破坏阶段中的分布特征,将3种模式的声发射信号分别对应于裂纹萌生、裂纹生长和微孔洞压缩闭合、裂纹汇合。实验结果表明,裂纹萌生、裂纹生长和微孔洞压缩闭合、裂纹汇合对应的声发射信号的上升时间依次增长、频率逐渐降低,与应变能释放理论相符合。
[Abstract]:In order to obtain the physical information of microcrack propagation and evolution in concrete in real time, the acoustic emission signals of three typical modes are identified by wavelet transform for each acoustic emission signal collected in the experiment. According to the change of event density of acoustic emission signal and the fracture theory of brittle materials, the compressive failure process of concrete is divided into micro-cavity compression closure and crack initiation. According to the inverse relation between acoustic emission signal frequency and crack source size and the distribution characteristics of acoustic emission signal in the four failure stages. The acoustic emission signals of the three modes are corresponding to the crack initiation, crack growth and pore compression closure, respectively. The experimental results show that the crack initiation, crack growth and micropore compression are closed. The rising time of acoustic emission signal corresponding to crack convergence increases in turn, and the frequency decreases gradually, which is consistent with the theory of strain energy release.
【作者单位】：北京理工大学爆炸科学与技术国家重点实验室;
【基金】：国家自然科学基金项目(11390363、11572049) 北京理工大学爆炸科学与技术国家重点实验室自主课题项目(YBKT16-16)
【分类号】：TU528
【正文快照】： 0引言混凝土是一种典型的非均匀准脆性复合材料。微裂纹演化及汇合是准脆性材料的主要损伤机制。混凝土内部裂纹在形成和扩展时,局部源快速释放能量、产生瞬态弹性波,即声发射现象[1]。声发射信号可以提供材料内部微观缺陷产生和发展的动态信息,利用声发射信号的特点能够检测

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