Weak form equation–based finite-element modeling of viscoelastic asphalt mixtures

Yuqing Zhang, Bjorn Birgisson, Robert L. Lytton

Research output: Contribution to journalArticle

Abstract

The objective of this study is to demonstrate using weak form partial differential equation (PDE) method for a finite-element (FE) modeling of a new constitutive relation without the need of user subroutine programming. The viscoelastic asphalt mixtures were modeled by the weak form PDE-based FE method as the examples in the paper. A solid-like generalized Maxwell model was used to represent the deforming mechanism of a viscoelastic material, the constitutive relations of which were derived and implemented in the weak form PDE module of Comsol Multiphysics, a commercial FE program. The weak form PDE modeling of viscoelasticity was verified by comparing Comsol and Abaqus simulations, which employed the same loading configurations and material property inputs in virtual laboratory test simulations. Both produced identical results in terms of axial and radial strain responses. The weak form PDE modeling of viscoelasticity was further validated by comparing the weak form PDE predictions with real laboratory test results of six types of asphalt mixtures with two air void contents and three aging periods. The viscoelastic material properties such as the coefficients of a Prony series model for the relaxation modulus were obtained by converting from the master curves of dynamic modulus and phase angle. Strain responses of compressive creep tests at three temperatures and cyclic load tests were predicted using the weak form PDE modeling and found to be comparable with the measurements of the real laboratory tests. It was demonstrated that the weak form PDE-based FE modeling can serve as an efficient method to implement new constitutive models and can free engineers from user subroutine programming.
Original languageEnglish
Article number04015115
JournalJournal of Materials in Civil Engineering
Volume28
Issue number2
Early online date30 Jul 2015
DOIs
Publication statusPublished - Feb 2016

Keywords

  • asphalt mixture
  • viscoelasticity
  • finite-element modeling
  • weak form partial differential equation
  • PDE
  • master curve
  • generalized Maxwell model

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