混凝土材料断裂过程中声发射空间自组织演化特征及其在结构失稳预报中的应用

利用声发射定位检测技术,对混凝土材料在三点弯曲断裂过程中,声发射事件的空间分布规律进行了观测.通过给出的声发射事件的位置熵函数,可以对这种空间演化规律进行定量描述.结合三点弯曲实验,对声发射空间演化规律同临界断裂的关系进行了分析.试验结果表明,混凝土试块在三点弯曲过程中,相应的声发射过程的空间自组织程度,随着应力状态的变化而变化.声发射空间位置熵的急剧下降,预示着宏观断裂的来临.

APPLICATION OF ACOUSTIC EMISSION TECHNIQUE TO PREDICT UNSTABLE FRACTURE IN CONCRETE

The acoustic emission is a technique at the micro?level.An attempt is made to study the spatial distribution of acoustic emission events during three?point bending notched tests of concrete. It can be described quantitatively by the position entropy of those events. The purpose of the paper is to provide some bases of the technique application. The relation between the spatial distribution and the critical fracture is discussed with the test data. The test results have shown that the degree of spatial distribution is varied with the stress state during the test. A dramatic decreasing of the position entropy is a signal to indicate the arrived unstable fracture.