In the small strain domain, asphalt mixes (AM) have a linear viscoelastic (LVE) behavior that is strongly dependent on frequency and temperature. The maximum ratio of modulus values can be up to 1000, and traditional elastic analyses are not pertinent. The possibility to characterize AM from frequency response functions (FRFs) was studied. A new optimization process using the finite element method (FEM) has been developed to back‐calculate the LVE properties of AM from FRFs. The numerical optimization process was applied to a reference material with averaged LVE properties determined from tension‐compression tests performed on a wide variety of AM types. The LVE properties were modeled considering the 3‐Dim version of the model 2S2P1D (2 Springs, 2 Parabolic elements, and 1 Dashpot). Reference FRFs for the considered reference material were obtained from FEM simulations. Three different configurations that may be of interest for practical tests were studied at five different temperatures. The proposed numerical optimization method consists in performing separate optimizations at each temperature to obtain the LVE properties for the considered temperature. Then values obtained at each temperature are considered to optimize 2S2P1D and Williams Landel Ferry (WLF) Equation constants to simulate the global LVE behavior of the material. The accuracy of the process was assessed regarding both the calculated FRFs and the complex modulus evaluation. Results indicate that the proposed optimization process converges almost perfectly towards the reference FRFs. The simulated complex modulus values are also in very good agreement with the values of the reference material.

中文翻译：

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动态频率响应函数的沥青混合料线性粘弹性行为

在小应变域中，沥青混合料（AM）具有线性粘弹性（LVE）行为，该行为强烈依赖于频率和温度。模量值的最大比率可以高达1000，并且传统的弹性分析是不相关的。研究了从频率响应函数（FRF）表征AM的可能性。已经开发出一种使用有限元方法（FEM）的新的优化过程，以从FRF中反算AM的LVE特性。将数值优化过程应用于参考材料，该材料具有通过对多种AM类型进行的拉伸压缩测试确定的平均LVE性能。LVE属性的建模考虑了模型2S2P1D的3-Dim版本（2个弹簧，2个抛物线元素和1个仪表盘）。从FEM模拟获得了用于考虑的参考材料的参考FRF。在五个不同的温度下研究了可能对实际测试有意义的三个不同配置。所提出的数值优化方法包括在每个温度下执行单独的优化以获得所考虑温度的LVE特性。然后考虑在每个温度下获得的值以优化2S2P1D和Williams Landel Ferry（WLF）方程常数，以模拟材料的整体LVE行为。关于计算的FRF和复模量评估，都评估了过程的准确性。结果表明，所提出的优化过程几乎完全收敛于参考FRF。