Linear Viscoelasticity
Elastic Response
Viscous Response
Maxwell Model
Creep
Stress Relaxation due to Maxwell
Voigt Model
Creep due to Voigt Relaxation
Combination of Maxwell and Voigt
Burgers Model
Generalized Models
Continues Distribution: Maxwell
Continues Distribution: Voigt
Superposition Principle
Dynamic Response Output: Input: Viscoelastic body For a dashpot: Stress: Moduli:
Complex Representation:
Time Scales
TTT (if it would be right….) It is because
Master curve for Polymers
Composition of Relaxations: phase shift
Comparison of E(T) and E(t)
General Constitutive Law We can re-write this in the form: than we generalize the Elastic law: If we define and, for example: It might be shown that
Laplace Transform
Properties of Laplace Transform
Linear Viscoelasticity (no time, so far)
Laplace… Laplace transform of this function leads to Similarly for m Finally:
Examples of Operators Boltzmann kernel Boltzmann without singularity No infinite rate of deformation
Homework Pick a Linear viscoelastic moduli Solve the Lame problem