Viscoelastic behavior of organic materials: consequences of a logarithmic dependence of force on strain rate.
The viscoelastic and -plastic behavior of organic materials like bone, tendon or wood, as well as technical polymers, is amply documented. It is usually modeled using linear "Newtonian" friction, i.e., a viscous force proportional to the deformation rate. If the experimental results cannot be fitted with the resulting exponential "Debye" curves, a multitude of relaxation mechanisms or a spectrum of relaxation times is invoked. In this contribution experimental evidence is compiled which indicates that for polymers and organic materials a logarithmic dependence of the deformation force on the deformation rate is more appropriate. The corresponding equation of motion is solved in the quasi-static approximation and the solutions display just the typical deviations from the Debye behavior found experimentally, without any complications from multi-mechanism relaxation.
Jäger
Ingomar L
IL
Institute of Metal Physics, University of Leoben, and Erich-Schmid-Institute of Materials Science, Austrian Academy of Sciences, Leoben, Austria. ingomar@unileoben.ac.at
D016880:Anisotropy; D001672:Biocompatible Materials / Q000032:analysis* / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D008422:Materials Testing / Q000379:methods*; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D009930:Organic Chemicals / Q000032:analysis* / Q000737:chemistry*; D013314:Stress, Mechanical; D014783:Viscosity
D001672:Biocompatible Materials; D009930:Organic Chemicals