基于声发射技术的混凝土受压损伤特征  

Damage Characteristics of Concrete Under Compression Based on Acoustic Emission Technology

作　　者：吴琛 杨金沙 李巧 WU Chen;YANG Jinsha;LI Qiao(Fujian Key Laboratory of New Technology and Information Technology in Civil Engineering,Fujian University of TechnologyFuzhou,350118,China;CSCEC Strait Construction and Development Co.,Ltd.Fuzhou,350015,China)

机构地区：[1]福建理工大学福建省土木工程新技术与信息化重点实验室,福州350118 [2]中建海峡建设发展有限公司,福州350015

出　　处：《振动．测试与诊断》2024年第3期608-613,626,共7页Journal of Vibration,Measurement & Diagnosis

基　　金：国家自然科学基金资助项目(52378494);福建省自然科学基金资助项目(2022H6032)。

摘　　要：为研究混凝土在受压过程中的损伤演化特征,开展多种强度混凝土试块受压全过程声发射动态检测。根据声发射撞击数“两峰值、三阶段”的演化特性和波形信号频谱特征,分别对应混凝土在初始压密阶段、裂缝开展阶段、裂缝贯穿阶段的损伤特征,并基于声发射速率过程理论和损伤力学建立以声发射累积撞击数表征的混凝土损伤因子。研究结果表明:各强度等级的混凝土在受压全过程中低频能量稳定在区间30 kHz~50 kHz内;当能量密集出现在高频区间时代表混凝土进入裂缝开展阶段,受载后期高频信号能量的明显衰减是混凝土破坏的前兆信息;基于累积撞击数所建立的损伤指标能较好地反映混凝土在不同应力水平下的损伤程度。To investigate the damage evolution characteristics of concrete under compression,acoustic emission dynamic detection is carried out for concrete specimens with various strengths in the whole process of com‑pression.The acoustic emission impact number and waveform characteristics reflect the evolution characteristics of“two peak values and three stages”of concrete damage,which correspond to the damage characteristics of concrete at the initial compaction stage,crack development stage and crack penetration stage respectively.Based on the theory of acoustic emission rate process and damage mechanics,the damage factors of concrete,which are characterized by acoustic emission cumulative impact count,are established.The results show that the energy of concrete with different strength levels is stable in the low frequency range of 30 kHz~50 kHz during the whole process of compression,and when the energy density appears in the high frequency range,it represents that the material enters the crack development stage.The obvious attenuation of the high frequency signal energy at the later stage of loading is the precursor information of concrete failure.The damage index based on cumulative impact number can reflect the damage degree of concrete under different stress levels.

关 键 词：声发射 频谱分析 速率过程理论 混凝土受压损伤 

分 类 号：TU528[建筑科学—建筑技术科学]