混凝土轴压荷载微裂缝宽频非线性声场激励检测  

The detection of concrete microcracks under compressive loading based on nonlinear ultrasonics modulation with broadband excitation

作　　者：王青原 许颖 樊悦 徐婷婷 WANG Qingyuan;XU Ying;FAN Yue;XU Tingting(Shenzhen Key Lab of Urban Civil Engineering Disaster Prevention&Reduction,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China;Shenzhen Key Laboratory of Intelligent Structure System in Civil Engineering,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China)

机构地区：[1]哈尔滨工业大学(深圳)深圳市城市与土木工程防灾减灾重点实验室,广东深圳518055 [2]哈尔滨工业大学(深圳)深圳市土木工程智能结构系统重点实验室,广东深圳518055

出　　处：《振动与冲击》2022年第18期184-191,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金面上基金(52078173,51778191);深圳市重点实验室筹建启动项目(ZDSYS20200810113601005)。

摘　　要：受压荷载作用下混凝土微裂缝损伤的产生和发展对于特殊混凝土结构具有较大影响。该文章从理论上分析了混凝土材料受压开裂初期固体内产生非线性调制现象的原理,关联混凝土材料微裂缝密度与非线性声场调制作用下的非线性响应改变量。有限元模拟了混凝土材料的细观非线性及微裂缝开展,探究非线性声场调制作用下不同开裂状态微裂缝处的开合状态及非线性调制超声信号的传播特性。发现当压缩应力小于5%极限压缩应力范围内时,非线性声场技术的边代峰计数损伤指标变化远比数字图像法测得的微裂缝密度改变明显,对微裂缝的表征具有优势。通过试验研究发现,该方法对宽度为80μm及以下的微裂缝产生和扩展具有较好的可测性,当损伤指标峰值计算结果为(0.02,0.2)区间时,混凝土材料产生微裂缝。在混凝土稳定损伤阶段,该研究给出了损伤指标峰值与裂缝密度的线性回归数值关系。The initiation and propagation of microcrack damage in concrete under compression loading have a great influence on structures that require a high level of concrete durability.The nonlinear acoustic modulation mechanism in concrete at the initial stage of compression cracking was theoretically analysed and the relationship between the microcrack density of concrete and nonlinear response variation was explored.The nonlinear behavior and microcrack development of concrete were simulated by the finite element method.The opening/closing state of microcracks under different cracking situations and the propagation characteristics of nonlinear acoustic modulated signals were investigated.It is found that the DI(damage index) of the SPC(side peak count) difference of the nonlinear acoustic field technology is much more sensitive than that of the microcrack density measured by DIC method.The experimental results show the good feasibility of the method proposed to detect microcracks with the width of 30-80 μm.Moreover,the experiment results find that when the peak value of DI is from 0.02 to 0.2,microcrack occurs in concrete.The linear regression numerical relationship between the peak value of DI and microcrack density was given in the stable-damage stage of concrete.

关 键 词：混凝土微裂缝 非线性声场调制技术 微裂缝密度 边代峰计数法 损伤指标 

分 类 号：TU528[建筑科学—建筑技术科学]