Full-field measurement and fracture and fatigue characterizations of asphalt concrete based on the SCB test and stereo-DIC
Full-field measurement and fracture and fatigue characterizations of asphalt concrete based on the SCB test and stereo-DIC
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基于SCB试验和立体DIC的沥青混凝土全场测量及断裂和疲劳表征
DOI：
10.1016/j.engfracmech.2020.107127
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发表时间：
2020-08-01
影响因子：
5.4
通讯作者：
He, Xiaoyuan
中科院分区：
文献类型：
--
作者：
Yuan, Fang;Cheng, Long;He, Xiaoyuan
采用立体数字图像相关技术，研究了沥青混凝土在半圆弯荷载作用下的全场位移场和应变场。断裂和疲劳测试分别使用两台像素分辨率为1520 x 1160的500帧/秒（fps）高速摄像机和两台像素分辨率为2048 x 2048的50帧/秒中速摄像机进行。验证了三种散斑图的准确性。此外，在断裂和疲劳试验中的平面外位移进行了测量。结果表明，在SCB测试中，离面位移的影响不可忽略，必须用立体DIC代替2D-DIC。基于立体DIC反演的沥青混凝土全场位移场和应变场，定量研究了沥青混凝土的断裂和疲劳特性。断裂试验表明，裂缝尖端塑性区的大小远小于裂缝长度，因此可以采用线弹性理论分析沥青混凝土的裂缝扩展行为。进一步计算了断裂能，为实际路面的数值模拟和建模服务。疲劳试验表明，在循环加载过程中，沿主裂纹附近区域沿着出现了许多细小的二次裂纹。基于损伤区域的平均应变，最终得到损伤-疲劳循环曲线，对沥青混凝土损伤进行评估。
This study investigated the full-field displacement and strain fields of asphalt concrete under semi-circular bending (SCB) through the stereo-digital image correlation (stereo-DIC) technique. Fracture and fatigue tests were conducted with two high-speed cameras at 500 frames per second (fps) with a pixel resolution of 1520 x 1160 and two medium-speed cameras at 50 fps with a pixel resolution of 2048 x 2048, respectively. The accuracy of the three kinds of speckle patterns was verified. Further, the out-of-plane displacements in both fracture and fatigue tests were measured. The results indicate that the effects of the out-of-plane displacement cannot be ignored in the SCB test, and stereo-DIC must be used instead of 2D-DIC. The fracture and fatigue characteristics of asphalt concrete were investigated quantitatively based on the full-field displacement and strain fields retrieved by stereo-DIC. The fracture test indicates that the size of the plastic zone at the crack tip is much smaller than the crack length; hence, the linear elastic theory can be used to analyze the crack propagation behavior of asphalt concrete. The fracture energy was further calculated to serve the numerical simulation and modeling of the actual pavement. The fatigue test indicates that many small secondary cracks occur along the area near the main crack during cyclic loading. Based on the average strain of the area of damage, the damage-fatigue cycle curve was finally obtained to assess the asphalt concrete damage.