基于CT技术和有限元方法的沥青混合料数值蠕变试验研究

Numerical creep test of asphalt mixture based on X-ray computed topography and finite element method

为弄清二维条件下,均质模型与非均质模型对数值蠕变试验结果的影响以及数值蠕变试验中最佳试验面的选取问题,基于X-ray CT技术和数字图像处理技术,采用Burgers模型表征沥青砂浆和沥青混合料的黏弹性,并利用有限元方法建立二维数值模型研究上述两种模型的蠕变试验特性,通过建立三个沿试件高度方向截面的数值模型分析最佳试验面的位置.结果表明,与均质模型相比,非均质模型数值试验的蠕变变形曲线与室内试验结果吻合度较高,沿试件高度方向不同截面的数值模型的蠕变变形曲线变化基本相同,且非均质模型可以显示试件内部各组分相的复杂应力分布状态.以上结果表明,非均质蠕变模型可以更准确地模拟室内蠕变试验,且沿试件高度方向的任意截面均可作为最佳试验面.

To analyze the effect of homogeneous model and heterogeneous model on the results of numerical simulation and the choice of optimum test section in creep test under twodimension numerical condition,X-ray computed technique and digital image processing technique were performed and the Burgers model was adopted to characterize the viscoelasticity of asphalt mortar and asphalt mixtures,and furthermore numerical model was established based on finite element method to study creep behaviors for homogeneous model and heterogeneous model and analyze the location of the optimum test section through choosing three sections along the height direction of the specimen.Results show that creep deformation curves of numerical test of heterogeneous model was close to laboratory test,and the variety of creep deformation curves of numerical experiment for different sections along the height direction of the specimen is almost consistent.Moreover,heterogeneous model displays the distribution of complicated stress of every component in the specimen.Therefore,heterogeneous model can simulate the laboratory creep test more accurately,and every test section of it can be chosen arbitrarily to be the optimum test section.