Investigation of Viscoelastic-Viscoplastic-Viscodamage Behavior of Polymers under Cyclic Loadings and Parametric Study of Their Mechanical Behavior

Document Type : Research Article

Authors

1 School of Mechanical Engineering, College of Engineering, University of Tehran, Iran

2 Assistant professor, School of mechanical engineering, University of Tehran

3 Department of Mechanical Engineering, Sharif University of Technology, Iran

Abstract

Nowadays, polymers have attracted many researchers due to individual properties in responding to mechanical loadings. According to their time and rate-dependent response to the exterior loads, there was too much complexity to predict mechanical responses. Thus, a thermodynamically consistent viscoelastic-viscoplastic-viscodamage model is considered to predict their mechanical responses. Along with this purpose, the explicit time-discrete form of the constitutive model is used in the finite element software ABAQUS by VUMAT subroutine. This method is valuable since its accuracy, low running time and no need for Jacobian matrix calculations. After validating ABAQUS user subroutine with experimental data obtained from creep, creep-recovery and repeated creep-recovery tests on the polymer, constitutive model sensitivity to the material parameters such as viscoelastic, viscoplastic and damage properties has been investigated. Along with this purpose, it can be observed that increasing viscoplastic and damage parameters could cause rising in the viscoplastic strain and damage variable. Then, the direct effects of loading time and stress level and the indirect effects of unloading time on the polymer strain and damage variable were investigated in the two repeated creep-recovery tests with constant and increasing amplitudes. For instance, doubling the increasing amplitude cycle number from 50 to 100 could rise service life and decrease about 75 percent of damage level.

Keywords

Main Subjects


[1] H.F.  Brinson,  L.C.  Brinson,  Polymer engineering science and viscoelasticity, Springer, 2015.
[2] W. Xu, G. Li, Constitutive modeling of shape memory polymer  based  self-healing  syntactic foam, International Journal of Solids and Structures, 47(9) (2010) 1306-1316.
[3] M.K. Darabi, R.K.A. Al-Rub, E.A.  Masad, C.-W. Huang, D.N. Little, A thermo-viscoelastic–viscoplastic– viscodamage constitutive model for asphaltic materials, International Journal of Solids and Structures, 48(1) (2011) 191-207.
[4]  R.K.A. Al-Rub, M.K. Darabi, D.N. Little, E.A. Masad, A micro-damage healing model that improves prediction of fatigue life in asphalt mixes, International Journal of Engineering Science, 48(11) (2010) 966-990.
[5]   H. Shahsavari, R. Naghdabadi, M. Baghani, S. Sohrabpour, A viscoelastic–viscoplastic constitutive model considering damage evolution for time dependent materials: Application to asphalt mixes, International Journal of Damage Mechanics, 25(7) (2016) 921-942.
[6] J. Lemaitre, A course on damage mechanics, Springer Science & Business Media, 2012.
[7] E. Masad, L. Tashman, D. Little, H. Zbib, Viscoplastic modeling of asphalt mixes with the effects of anisotropy, damage and aggregate characteristics, Mechanics of Materials, 37(12) (2005) 1242-1256.
[8] M.K. Darabi, R.K.A. Al-Rub, D.N. Little, A continuum damage mechanics framework for modeling micro- damage healing, International Journal of Solids and Structures, 49(3-4) (2012) 492-513.
[9] M.K. Darabi, R.K.A. Al-Rub, E.A. Masad, D.N. Little, A thermodynamic framework for constitutive modeling of time-and rate-dependent materials. Part II: Numerical aspects and application to asphalt concrete, International Journal of Plasticity, 35 (2012) 67-99.
[10] R.K.A. Al-Rub, M.K. Darabi, A thermodynamic framework for constitutive modeling of time-and rate-dependent materials. Part I: Theory, International Journal of Plasticity, 34 (2012) 61-92.
[11] R.K. Abu Al-Rub, M.K. Darabi, C.-W. Huang, E.A. Masad, D.N. Little, Comparing finite element and  constitutive modelling techniques for predicting rutting of asphalt pavements, International Journal of Pavement Engineering, 13(4) (2012) 322-338.
[12] M.M. S. Aghasizade Shaarbaf, Identification of Tire Force Model Using Experimental Data of a New Scaled Test Rig for Design of Nonlinear Slip Controller, Amirkabir Journal of Mechanical Engineering, 51(1) (2019) 187-200 (in Persian).
[13]R.K. Abu Al-Rub, A.H. Tehrani, M.K. Darabi, Application of a large deformation nonlinear- viscoelastic viscoplastic viscodamage constitutive model to polymers and their composites, International Journal of Damage Mechanics, 24(2) (2015) 198-244.
[14] M.K. Darabi, R.K.A. Al-Rub, E.A. Masad, D.N. Little, Thermodynamic-based model for coupling temperature-dependent viscoelastic, viscoplastic, and viscodamage constitutive behavior of asphalt mixtures, International Journal for Numerical and Analytical Methods in Geomechanics, 36(7) (2012) 817-854.