基于ESPI和DIC技术的混凝土断裂特性研究及对比分析  

Study on and comparative analysis of concrete fracture properties using ESPI and DIC technologies

作　　者：黄兴震 陈红鸟[1] 刘轶 肖建春[1] 王青原[1] 

机构地区：[1]贵州大学空间结构研究中心,贵阳550003 [2]贵州大学土木工程学院,贵阳550025

出　　处：《应用力学学报》2018年第5期1131-1138,共8页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51408144);贵州省科学技术基金([2016]1040);贵州省留学人员科技创新项目([2016]17)

摘　　要：采用电子散斑干涉(ESPI)技术和数字图像相关(DIC)技术对带预制裂缝的三点弯曲混凝土梁进行了测量,研究了普通混凝土(混凝土强度f_(cu)=33.2MPa)和高强混凝土(f_(cu)=65.1MPa)的断裂特性。结果表明:各组试件的P-δ曲线离散性较大,但P-CMOD曲线吻合度较高,在峰值荷载处,临界裂缝尖端张开位移(CTOD_c)分别为21mm和29mm;从试验裂缝张开位移(COD)曲线确定裂缝扩展长度,两种混凝土的裂缝扩展长度与韧带高度之比分别为1∶4和1∶3。分析了两组试件的荷载-裂缝扩展长度关系规律。与夹式位移计测量结果对比发现,ESPI和DIC均可替代传统测量仪器得到比较准确的测量结果,当试件变形较大(CMOD>0.25mm)时,ESPI的测量误差较大,而DIC误差一直保持在0.03mm以内。分析了两种技术测量误差产生的原因,对降低实验误差提出了一些建议。Electronic Speckle Pattern Interferometry(ESPI) and Digital Image Correlation(DIC) technologies are used to measure the displacement fields of pre-notched concrete beams subjected to three-point bending. Fracture properties of concrete including normal strength concrete(NSC)(concrete strength f_(cu)=33.2 MPa) and high strength concrete(HSC)(f_(cu)=65.1 MPa) are studied. Experimental results indicate that P-δ curves of different samples are dispersed while P-CMOD curves are in excellent agreement. From crack opening displacement(COD) curve, crack lengths at different loading levels are determined. At the peak, crack length to ligament length ratios for NSC and HSC are 1∶4 and 1∶3 respectively and critical crack tip opening displacement(CTOD_c) are 21mm and 29mm respectively. In addition, relationship of the crack propagation and loads are analyzed. ESPI and DIC results are compared with that measured by clip gauge and excellent agreement is found, demonstrating the applicability of ESPI and DIC techniques. As DIC measurement is more stable, it can replace traditional measurement instrument. Finally, measurement errors caused by the two techniques are analyzed and some suggestions to reduce the errors are given.

关 键 词：电子散斑干涉 数字图像相关 混凝土 裂缝扩展长度 裂缝张开位移 

分 类 号：TU528[建筑科学—建筑技术科学]