基于电子散斑干涉技术的混凝土断裂性能研究  

Study on Fracture Properties of Concrete by Using Electronic Speckle Pattern Interferometry Technique

作　　者：赵艳兵[1] 陈红鸟[1] 刘春[1] 孙敬明 才琪[1] 

机构地区：[1]贵州大学空间结构研究中心,贵州贵阳550003

出　　处：《建筑科学》2016年第7期66-73,共8页Building Science

基　　金：混凝土的拉伸软化曲线及其尺寸效应研究(51408144);改性工业废弃石膏材料力学性能研究(X131001);蜂窝型钢空腹夹层板的刚度及其应用的研究(2016001)

摘　　要：为研究混凝土断裂性能,对预制切口混凝土梁进行三点弯曲试验,利用电子散斑干涉(Electronic Speckle Pattern Interferometry,ESPI)技术测量梁表面的场位移。为进行对比分析,采用线性位移传感器(Linear Variable Differential Transformers,LVDTs)和夹式位移计分别测量试件梁的跨中挠度(δ)和裂缝口张开位移(Crack Mouth Opening Displacement,CMOD)。试验结果表明:ESPI测量的结果与LVDTs、夹式位移计测得结果比较吻合,证实了ESPI测量梁表面场位移的精确性和可行性。在峰值荷载,CMOD约为27μm,挠度δ约为58μm,裂缝尖端位移CTOD约19.2μm。ESPI结果表明,试件梁主裂缝起始于预制切口尖端,沿着接近切口平面的路径向试件梁顶部的加载点扩展,裂缝轨迹呈蜿蜒状。断裂过程区集中在梁跨中附近,宽度约为10mm^15mm,在裂缝发展初期呈核状,在裂缝发展后期呈不规则的狭长带状。Three-point bending tests are performed on pre-notched concrete beams to study the fracture properties of concrete. Electronic Speckle Pattern Interferometry（ ESPI） technology is used to measure the full-field displacements of concrete beams. Linear Variable Differential Transformers（ LVDTs） and clip gauge extensometer are used to measure the min-span deflection and Crack Mouth Opening Displacement（ CMOD） of the beam respectively. The experimental results indicate that the displacements measured by ESPI agree well with the results of LVDTs and clip gauge,verifying the accuracy and feasibility of ESPI measurement. At the peak load,CMOD is about 27μm,mid-span deflection is about 58μm and crack tip opening displacement（ CTOD） is about 19. 2μm.ESPI results show that,the main crack initiates from the tip of the pre-notch and propagated along a path close to the notch plane to the upper support. Its trajectory is winding. The fracture process zone（ FPZ） of concrete occurred near the mid-span of the beam and its width is about 10 mm ~ 15 mm. At the early stage of crack evolution,the shape of the FPZ is similar to core; while at the final stage,the shape exhibits an irregular strip.

关 键 词：ESPI 三点弯曲 混凝土梁 断裂性能 裂缝 

分 类 号：TU528[建筑科学—建筑技术科学]