基于亚像素边缘检测方法的橡胶裂纹扩展实验研究  

Research on fatigue crack growth experiment using sub-pixel edge detection method

作　　者：陈鹏书 刘思轲 李子然[1] 汪洋[1] CHEN Pengshu;LIU Sike;LI Ziran;WANG Yang(CAS Key Laboratory of Mechanical Behavior and Design of Materials,Department of Modern Mechanics,University of Science and Technology of China,Hefei 230027,Anhui,China)

机构地区：[1]中国科学院材料力学行为和设计重点实验室,中国科学技术大学近代力学系,安徽合肥230027

出　　处：《实验力学》2023年第3期340-346,共7页Journal of Experimental Mechanics

摘　　要：橡胶疲劳裂纹扩展实验中,通常采用光学方法测量裂纹扩展长度,但其精度受限于相机分辨率。本研究采用canny算子对拍摄的裂纹图片进行边缘检测,并对裂尖边缘进行线性插值得到亚像素级精度的裂纹尖端坐标,可在相机分辨率固定的情况下有效提高测量裂纹扩展长度的精度。在此基础上,首先开展了室温下合成橡胶的裂纹扩展疲劳实验,即采用恒幅加载方式对预制裂纹的矩形试件进行平面拉伸。然后使用亚像素边缘检测方法获得了更为精确的裂纹扩展速率,结合准静态拉伸实验得到的撕裂能数据,拟合得到了合成橡胶的疲劳裂纹扩展特性参数。最后将亚像素边缘检测方法与传统光学测试方法进行了对比,发现该方法所得数据稳定性更好,裂纹扩展速率的测算更为精确,在记录间隔循环次数较短的情况下具有明显的优势。The optical method is usually used to measure the crack growth length in the rubber fatigue crack growth experiment,but its accuracy is limited by the resolution of the camera.In this study,the canny operator was used to detect the edge of the crack image,and for the crack tip edge,linear interpolation was used to obtain the crack tip coordinate with sub-pixel accuracy,which can effectively improve the accuracy of crack growth length under the condition of a certain camera resolution.On this basis,the fatigue crack growth experiment of synthetic rubber at room temperature was carried out,that is,the rectangular specimen with prefabricated cracks was subjected to plane tension by constant amplitude loading.The sub-pixel edge detection method was used to obtain a more accurate crack growth rate.Combined with the tearing energy data obtained from the quasi-static tensile test,the fatigue crack growth characteristic parameters of synthetic rubber were obtained by fitting.Finally,the above method was compared with the traditional optical testing method,and it is found that the data obtained by this method is more stable,the measurement of the crack growth rate is more accurate,and it has obvious advantages when recording intervals are short.

关 键 词：橡胶疲劳 裂纹扩展 边缘检测 亚像素 

分 类 号：TB115[理学—数学]