沥青混合料间接拉伸试验的数值模拟

Numerical simulation of indirect tensile test for asphalt mixture

为了阐释沥青混合料间接拉伸试验中马歇尔试件对荷载的动态响应规律,利用离散元方法(二维)数值模拟了马歇尔试件的间接拉伸试验过程。采用伺服控制机理对不同粒径的试件施加荷载,给出了颗粒间的接触力、颗粒的位移矢量及产生的裂缝数,得到试件的劈裂强度;对不同加载速率下试件的响应进行数值模拟,得出加载速率与劈裂强度的关系;选取一种粒径范围的试件,分析了试件中产生的裂缝随时间的发育和分布,再现了裂缝延伸的动态过程。结果表明:裂缝主要分布于加载方向试件直径的两侧,随着粒径的增大,劈裂强度增大,增长率最大为39.3%;裂缝数由最小粒径试件中的98条减至最大粒径试件中的6条;加载速率与劈裂强度呈对数增长关系。

To illustrate the dynamic response laws of Marshall specimen to load with indirect tensile test of asphalt mixture,the indirect tensile test of Marshall specimen was simulated by discrete element method（two dimension）.The specimens with different diameters of particles were imposed to load using servo-control mechanism,the contact forces between particles,displacement vectors of particles and the number of cracks were given,and the splitting strengths were obtained.The responses of specimens were simulated numerically under different load rates,then the relationship between splitting strength and load rate was gotten.In addition,selecting a speci-men with one diameter of particles,the growth and development of cracks with time were analyzed to show the dynamic process of crack extension.The results indicate that the cracks mainly distribute on both sides of the diameter of specimen along load direction,the splitting strength increases as the diameter of particles increases and the maximum growth rate is 39.3%,the number of cracks decreases from 98 in specimens with the smallest diameter of particles to 6 in specimens with the largest diameter of particles,the relationship between load rate and splitting strength is logarithmic curve.2 tabs,8 figs,12 refs.