基于EMI技术的混凝土冲击损伤演化特性

Study on damage evolution characteristics of concrete under impact based on EMI technology

采用压电阻抗(EMI)技术探究了C50混凝土在冲击荷载作用下的损伤演化特性,并基于EMI技术与动态弹性模量测试原理之间的内在联系,设置了平行对照试验,验证了EMI技术应用于混凝土冲击损伤监测的敏感性与准确性.在此基础上,针对不同损伤程度的试件进一步开展劈裂抗拉强度试验,揭示基于EMI测试技术的损伤量--电导信号的均方根偏差值(RMSD)与混凝土宏观力学参数之间的经验关系.损伤测试试验结果表明:EMI技术能够很好地实现对混凝土试件损伤发展状态的监测,并且可根据RMSD值的变化特点,给出试件失效的预警信息.力学强度试验结果显示:在具体边界条件下,混凝土试件的劈裂抗拉强度将随RMSD值呈指数型下降,可据此对试件的承载能力做出定量的评估与预测.

In this paper, the damage evolution characteristics of C50 concrete under impact loading were studied based on electro-mechanical impedance(EMI) technology.In order to verify the sensitivity and accuracy of the experimental result,a parallel contrast test was designed based on the internal relation between EMI technology and dynamic elastic modulus testing. Another mechanical test was conducted on specimens with different damages to establish the empirical relation between damage quantity and macro-mechanical parameters of concrete.The experimental results clearly illustrate that damage evolution of concrete can be well monitored by PZT(piezoelectric ceramic transducer) patch.Based on the changing index of RMSD(root-mean-square deviation),warning information for failure can be obtained. On the other hand, mechanical test results indicate that the value of RMSD is correlated with the splitting tensile strength of the concrete specimen under the specific boundary conditions.Therefore,it can be used as a reference to quantify and predict the performance of concrete.