In: Physics
Explain the term ‘strain rate sensitive’. Show your references.
Strain rate sensitive means a material's stress versus strain
characteristics are dependent on the RATE of loading.
Strain rate is the change in strain(deformation) of a material with
respect to time.
The strain rate at some point within the material measures the rate
at which the distances of adjacent parcels of the material change
with time in the neighborhood of that point. It comprises both the
rate at which the material is expanding or shrinking (expansion
rate), and also the rate at which it is being deformed by
progressive shearing without changing its volume (shear
rate).
Case 1
Load a material fast and you get a stress versus strain
diagram.
Case 2
Load the same material slow and you get another stress versus
strain diagram.
If the stress strain diagrams are DIFFERENT for case 1 and case 2
then the material IS strain rate sensitive.
If the stress strain diagrams are the SAME for case 1 and case 2
then the material IS NOT strain rate sensitive.
At room temperature steel is regarded as NOT strain rate
sensitive.
Viscoelastic materials are strain rate sensitive.