沥青混合料预缺口试件直接拉伸疲劳损伤分析  

Fatigue Damage Analysis of Asphalt Mixture Specimen with Pre-made Gaps in Direct Tension Test

作　　者：周志刚[1] 袁秀湘[1] 谭华 

机构地区：[1]长沙理工大学道路结构与材料交通行业重点实验室,湖南长沙410004 [2]广西交通科学研究院,广西南宁530007

出　　处：《中国公路学报》2013年第1期30-37,共8页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(50778027);湖南省自然科学基金项目(04JJ3033);广西壮族自治区交通科技计划项目(0992009-5)

摘　　要：为了研究沥青混合料疲劳损伤断裂特性,应用断裂力学积分守恒定律,提出一种关于沥青混合料对称边缺口试件拉伸疲劳损伤的封闭解法,并根据有限元计算与有关试验结果的对比,确定了合适的试件缺口处应力集中系数和沥青混合料疲劳损伤特性参数,同时证明了在拉伸疲劳试验情况下所提出的沥青混合料非线性疲劳损伤模型的有效性。根据非线性有限元计算,分析了沥青混合料含缺口试件拉伸疲劳损伤开裂、裂纹扩展过程,讨论了不同阶段试件内部损伤度、拉应力的分布规律,以及它们和试件位移、疲劳寿命随预制裂纹起裂、扩展的变化规律。研究结果表明:基于疲劳损伤有限元和Paris公式的沥青混合料含缺口拉伸试件的疲劳损伤分析结果与直接拉伸疲劳试验结果基本一致,但基于Paris公式的计算结果无法反映试件在起裂和扩展初期阶段裂纹扩展速率的变化情况。In order to study the fatigue damage and cracking of asphalt mixture, a confining solution for fatigue damage of asphalt mixture specimen with gaps at edges symmetrically wasproposed based on the law of conservation of integral in fracture mechanics. The suitable stress concentrating coefficient at the gaps and fatigue damage characteristic parameters of asphaltmixture were determined according to the comparison between the results of FEM and testing. And the validity of the nonlinear fatigue damage model proposed under tension fatigue test wasproved. By using nonlinear finite element method, the process of the specimen fatigue damage and cracking, the distribution of damage indexes and tension stresses in specimens at differentstages, and the changing laws of them and displacements and fatigue lives of specimens were discussed. The results show that testing results are consistent with that of calculation based onfatigue damage FEM and Paris equation. But the results based on Paris equation can not describecrack spreading velocity at crack initiation and during its initial spreading.

关 键 词：道路工程 沥青混合料 直接拉伸疲劳试验 非线性疲劳损伤 仿真 

分 类 号：U414.75[交通运输工程—道路与铁道工程]