基于CT技术和有限元方法的沥青混合料虚拟劈裂试验研究

Simulation splitting test of asphalt mixture based on X-ray computer technique and finite element method

为弄清劈裂荷载条件下,沥青混合料试件内部的应力分布状态,基于X-ray CT技术、数字图像处理技术和有限元方法建立二维非均质数值模型,分析通过试件中心的垂直方向与水平方向路径条件下不同位置截面的内部应力分布情况,并与均质模型内部应力进行比较.结果表明,与均质模型不同,不同位置截面的非均质模型内部应力峰值没有出现在模型中心处,而是分布在试件中部呈现多峰值状态且较好地反应各个组分的力学行为;在分析路径上,不同位置截面的非均质模型应力分布趋势相同,但应力峰值出现的位置以及应力最大值均存在差异,说明试验截面的选取对二维虚拟试验结果影响较大.

To analyze stress distribution in asphalt mixture inter- nal structure under splitting load condition, two-dimension heter- ogeneous numerical models are established based on X-ray com- puted technique, digital image processing and finite element method to study stress distribution in different sections under the path of vertical direction and horizontal direction of asphalt mix- ture specimen, and internal structure stress of the heterogeneous model and homogeneous model. Comparison results show that unlike homogeneous model, the peak value of internal stress of heterogeneous model at different sections is not shown in the mid-dle of the model, but is distributed in the central parts of the model which exhibits multi-peak value condition, moreover, it reflects mechanics behaviors of different components of asphalt mixtures. The stress distribution trend of heterogeneous models at different sections is identical on analysis path, but there are differences at the position of peak value and the maximum value of internal stress. Therefore, the selection of section has great impact on the result of the two-dimension simulation test.