混凝土材料三点弯曲破坏的声发射特性

为了研究碎石混凝土材料在不同应力状态下的声发射信号特征,在MTS材料试验机上对混凝土梁进行了三点弯曲实验,并利用先进的多通道声发射系统监测了混凝土梁在三点弯曲载荷下的破坏过程。通过对声发射信号的持续时间、振铃计数、撞击数进行滤波,将混凝土材料破坏过程的声发射信号分成七种类型,同时结合前人关于混凝土材料Kaiser效应的试验研究,将七种类型的声发射信号对应于不同的相对应力水平。研究结果表明,声发射信号的持续时间、振铃计数以及撞击数不仅可以表征混凝土破坏过程的类型,还可以表征混凝土材料所处的应力状态,从而为声发射技术在线监测混凝土材料提供了一种新的途径。

On the Acoustic Emission Characteristics of Concrete Fracture Subjected to Three-Point-Bending

In order to study acoustic emission signal characteristics of gravel concrete materials under different stress states, three-point-bending test of concrete beam was carried out on a MTS testing machine, and advanced multi-channels acoustic emission system was used to detect the fracture process of concrete beams subjected to three-point-bending loading. Concrete material fracture process may be divided into seven kinds based on filtering the signal emission duration, the counts and the hit numbers. According to the results of former experimental study about concrete material Kaiser effect, it was indicated that different kinds of acoustic emission signal corresponded to different relative stress levels. Results show that emission duration, counts and hit number of acoustic emission signals can not only characterize the concrete failure process types, but also characterize the concrete stress state. It provides a new way for on-line monitoring concrete material.