Mechanical behavior of amorphous polymers in shear



Based on the non-equilibrium thermodynamic theory, a new thermo-viscoelastic constitutive model for an incompressible material is proposed. This model can be considered as a kind of generalization of the non-Gaussian network theory in rubber elasticity to include the viscous and the thermal effects. A set of second rank tensorial internal variables was introduced, and in order to adequately describe the evolution of these internal variables, a new expression of the Helmholtz free energy was suggested. The mechanical behavior of the thermo-viscoelastic material under simple shear deformation was studied, and the “viscous dissipation induced” anisotropy due to the change of orientation distribution of molecular chains was examined. Influences of strain rate and thermal softening produced by the viscous dissipation on the shear stress were also discussed. Finally, the model predictions were compared with the experimental results performed by G' Sell et al., thus the validity of the proposed model is verified.

Key words

thermo-viscoelastic constitutive theory non-Gaussian network model finite deformation simple shear deformation non-equilibrium thermodynamics 

Chinese Library Classification

O343.6 O414.14 

2000 Mathematics Subject Classification

74D10 74C20 74F05 


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Copyright information

© Editorial Committee of Applied Mathematics and Mechanics 2004

Authors and Affiliations

  1. 1.State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering SciencePeking UniversityBeijingP.R. China

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