沥青混合料Ⅰ型疲劳开裂虚拟离散元试验

Virtual test of type Ⅰ fatigue crack of asphalt mixture based on discrete element method

采用离散单元法对Arcan I型开裂试验进行了虚拟试验.根据现实试验中的沥青混凝土试件集料-集料和集料-黏结料之间的力学关系,在虚拟试验中利用Burgers模型建模,并在电子扫描图像基础上使用Particle Flow Code3D软件建立虚拟试件.在虚拟试验过程中实时监测试件应力分布变化及观测点应变变化.结果表明：虚拟试验结果与实际试验符合良好;应力监测结果表明裂缝发展全程符合裂缝尖端应力集中现象,且初始微裂缝会沿尖端方向继续发展成为大裂缝;Arcan I型开裂试验中试件直接受拉,应力分布简单直观,应力-应变分析对比其他试验方法更为直观.

The type I Arcan cracking test was simulated by the discrete element method（DEM）.According to the mechanics relationship among aggregates and the relationship between aggregate and binder in the real asphalt concrete specimens,the Burgers model was used in the fatigue model.The images of CT scanning were obtained to analyze the aggregate？s characteristics in the real specimen which was simulated by a virtual specimen built in the PFC 3 D.The distribution and the change of the stress at the observation points were monitored in real-time,and the real test was also carried out to obtain the fatigue life of the real specimen.Results show that the fatigue life of the virtual specimen is close to the result in the real test.Result of the monitoring shows that the development process of crack is in accordance with the stress concentrated on the tip of the crack.Relationship between the area of crack and initial crack shows that the initial crack will develop to a greater one at one direction under the loading.Compared to other test methods,the stress strain analysis of type I Arcan cracking test are more intuitive.