【摘要】 基于声发射多角度分析了三点弯曲作用下混凝土梁损伤演化特征。通过声发射事件计数、振铃计数、能率和幅频极值等多参数分析,定性研究了混凝土梁三点弯曲作用下损伤累积过程;提出基于声发射幅频极值的损伤量,对损伤过程进行了定量分析;结合声发射事件定位点和损伤量,对混凝土梁受载过程中损伤累积过程进行了量化表征。结果表明,损伤主要发生在塑性阶段,在受拉区产生、聚集,快速向受压区发展,形成损伤带,导致试件脆性断裂。研究为混凝土梁灾变破坏预警和工程设计提供基础性的参考。更多还原

【Abstract】 The damage evolution characterization of concrete beams under three-point bending was analyzed from multiple perspectives based on acoustic emission. Multiparameter qualitative analysis including event count, ring count, energy rate and amplitude-frequency extremum were used to study the damage evolution characterization. The quantitative analysis of concrete damage evolution process was made based on the damage degree. According to the locations of acoustic emission events and the damage degree, the damage evolution process was represented intuitively. The results show that the damage mainly occurs in the plastic stage. Firstly, it occurs and gathers in the tension zone, then develops rapidly to the compression zone, and forms the damage zone which leads to brittle fracture of specimens. The study provides a basic reference for the early warning of concrete beam catastrophic damage and engineering design.更多还原