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为了探究沥青混合料的应力依赖性质,分别在不同应力状态及荷载频率下对一组AC-20试件进行了动态模量试验.开发了一个包含应力依赖本构模型的用户自定义材料子程序并利用有限元模拟证实了其有效性.建立了一个典型路面结构的三维有限元模型,将沥青面层视为应力依赖性材料,而其他结构层为线弹性材料.对路面模型施加周期性荷载,并计算得到路面响应,包括动态模量的分布、路表弯沉、沥青面层的剪应力及拉应变等.试验结果及有限元模型预测值均表明了沥青混凝土的动态模量对应力状态及荷载频率具有敏感性.与线弹性模型相比,使用非线性应力依赖模型得到的预测路面响应更大;应力依赖性对路面响应的影响随着荷载频率的减小变得更加显著.
In order to investigate the stress-dependent nature of asphalt mixtures, dynamic modulus tests were performed on a group of AC-20 specimens at different stress states and load frequencies respectively. A user-defined material subroutine including a stress-dependent constitutive model The finite element model is used to verify its effectiveness. A three-dimensional finite element model of a typical pavement structure is established, in which the asphalt pavement is regarded as stress-dependent material and the other structural layers are linear elastic materials. The pavement model is periodically loaded , Including the distribution of dynamic modulus, deflexion of road surface, the shear stress and tensile strain of asphalt surface, etc. The experimental results and the predictions of finite element model all indicate that the dynamic modulus of asphalt concrete is in agreement with the stress state And the frequency of the load are sensitive.Compared with the linear elastic model, the predictive pavement response obtained by the nonlinear stress-dependent model is larger than that of the linear elastic model. The effect of the stress dependence on the pavement response becomes more significant as the load frequency decreases.