基于DIC方法研究钢筋混凝土裂缝扩展规律分析

Investigation of the reinforced concrete crack propagation law based on the DIC method

针对钢筋混凝土裂缝扩展问题,进行了钢筋混凝土梁四点纯弯试验。应用数字图像相关(Digital Image Correlation,DIC)方法获得了梁体侧面的全场应变及位移信息。根据断裂力学的位移外推法计算了裂纹的应力强度因子(Stress Intensity Factor,SIF),并探讨了应力强度因子的变化规律及裂纹扩展规律。结果表明,应力强度因子随荷载增加而增加,并且主裂纹应力强度因子增长较快,次裂纹应力强度因子增幅较小。与传统的电阻应变计测试方法相比,数字图像相关方法能够准确观测钢筋混凝土的全场裂纹扩展过程,是一种值得推广的试验方法。

Pure bending tests for reinforced concrete beams were carried out to study the crack propagation of reinforced concrete beam.Digital Image Correlation（DIC）method was used to obtain the full strain and displacement information of beam body side.The stress intensity factor（SIF）of the crack was calculated by fracture mechanics displacement extrapolation method,and the change of the SIF and the regularity of crack propagation were discussed.The results show that the SIF increases as the increase of load,and the SIF of the main crack increases faster than the other cracks.Compared with traditional testing methods,the crack propagation process of the reinforced concrete can be observed visually DIC method.