基于数字图像的沥青混合料离散元几何建模方法

沥青混合料的性能与其细观结构密切相关,离散元方法在解决沥青混合料这种复杂、多相、不连续介质材料的细观问题时,具有很大优势。针对以往沥青混合料离散元建模不能较好模拟集料颗粒形状的问题,结合数字图像处理技术,提出了一种新的沥青混合料离散元几何建模方法,主要有3个步骤：1）使用特征聚类方法,将沥青混合料切片图像中的集料与沥青砂浆分离;2）并利用链码边界跟踪和线段表算法将分离的集料区域填充为离散元中的＂聚粒＂;3）用离散元的圆盘单元填充沥青胶砂区域,实现沥青混合料切片图像的二维离散元几何建模。利用该模型,较好地模拟了沥青混合料在贯入荷载作用下变形的动态过程。

A DEM Geometric Modeling Method of HMA Based on Digital Imaging Processing

The performance of asphalt mixture is closely related with microscopic structure.Discrete element method（DEM） has the great advantage in solving microscopic problem of the asphalt mixture with complex,multiphase and discontinuous medium materials.To solve the problem the past DEM could not perfectly simulate aggregate particle shape in HMA,a geometric modeling method of DEM based on the digital image processing was established.Firstly,the aggregate and asphalt mastic were separated from the sliced image of HMA using features clustering method.Then the aggregate ranges were filled with balls as DEM ＂clump＂ using chain code boundary tracking algorithm and lines table filling algorithm.Finally,the asphalt mastic regions were filled with balls.The simulation test of dynamic deformation process of asphalt mixture under penetration load are in good agreement with those from practice.