数字散斑图像处理技术在Nano-SiO₂改性混凝土劈裂拉伸试验中的应用

Application of Digitalimage Correlation Technology in Splitting Tensile Test of Concrete Modified by Nano-SiO₂

目前,数字散斑图像技术(DIC)是一种监测混凝土力学试验过程中性能指标变化较为新颖且有效的方法。基于该技术,采用非接触应变测量系统对纳米二氧化硅改性混凝土在劈裂拉伸试验过程中产生的变形进行实时数据采集,研究试样在破坏前、初始破坏以及完全破坏三个阶段的位移场和应变场的过程变化,分析不同阶段下试样水平方向位移场(U)和水平方向应变场(Exx)的变化规律。结果表明,试样在完全破坏时表面裂缝位移场U出现阶梯形状,应变场Exx出现峡谷状形。利用数字散斑技术可有效地监测试样在力学试验中的横向变形、裂缝萌生及扩展的全过程。

At present, digital image correlation technology (DIC) is a novel and effective method to monitor the change of performance parameters during the mechanical test of concrete. Based on this technology, the non-contact strain measurement system is adopted here to collect the deformation data of nano-SiO2 modified concrete during the splitting tensile test to study the changes of the displacement field and strain field in the three stages of pre-destruction, initial and complete failure, and analyze the variation rules of horizontal displacement field (U) and horizontal strain field (Exx) at different stages. The results show that the displacement field U of the surface crack has a step shape, while the strain field Exx has a ravine shape. The whole process of transverse deformation, crack initiation and propagation during mechanical test can be effectively monitored by digital speckle technique.