Module 1: Constitutive Equations

Constitutive Equations - Lesson Summary

Polymers are flexible molecules which can be stretched or deformed by weak forces.
The Two Types of Mechanics Laws are:
Conservation laws
Constitutive laws

Conservation laws are not universal as they often encode the behavior of specific materials and even experimental conditions.

The Constitutive Equation of state provides the linkage between stress and kinematics.
The issue of yield-stress is somewhat complicated by the fact that if one waits long enough everything flows.

The two types of flows that are used to characterize polymeric flows are:
Shear flow
Shear free flow
The three independently accessible values in a simple shear flow are:
Shear stress
First normal stress difference
Second normal difference