Seminar Schedule – Spring 2019

Tuesday, February 12, 2019
Time: 3:30pm – 5:00pm
Place: TBD

Mechanical Behavior of Polymer Glasses

James M. Caruthers, Purdue University

Polymers are one of the most important engineering materials used in a variety of applications – both as engineering materials in their own right and as the matrix resin in polymer composites. In these applications the mechanical properties of polymers are of paramount importance. Depending upon the composition, polymer solids can either be in a glassy or semi-crystalline state, where in this talk we will focus on polymer glasses. Unlike more traditional engineering materials like metals, ceramics, etc., the mechanical response of glassy polymers is inherently time-dependent and also a strong function of temperature, temperature history, strain rate, type of loading (i.e. strain controlled or stress controlled) and the loading history � all important variables in the life-cycle of a polymer component.

First, an overview of the diverse time and temperature dependent mechanical response of glassy polymers will be given. Description of this diverse thermo-mechanical behavior requires a nonlinear viscoelastic description. The key nonlinearity is that deformation affects the rate of viscoelastic relaxation, where there are a number of choices for what deformation variable controls the nonlinearity. Finally, in order to unify the diversity of thermomechanical phenomena exhibited by glassy polymers it appears that a constitutive model that includes stochastic fluctuations at the meso-scale is needed.

For further information, please contact Dr. Ken Liechti at kml@mail.utexas.edu or (512) 471-4164.