Choose the best option: - Viscoelastic stress relaxation - Viscoelastic creep Al
ID: 2086611 • Letter: C
Question
Choose the best option:
- Viscoelastic stress relaxation
- Viscoelastic creep
Although the viscoelastic response of a polymer can be very complex (time-dependent stress cycling for instance), two special loading scenarios are fairly simple to describe mathematically.
1. _______ refers to scenarios for which the stress applied to a polymer must decay over time in order to maintain a constant strain. Otherwise, over time, the polymer chains will slip and slide past one another in response to a constant applied load and the strain will increase (in magnitude).
2. ________ refers to scenarios for which a polymer will permanently flow over time in response a constant applied stress.
Explanation / Answer
1. Viscoelastic stress relaxation refers to scenarios for which the stress applied to a polymer must decay over time in order to maintain a constant strain. Otherwise, over time, the polymer chains will slip and slide past one another in response to a constant applied load and the strain will increase (in magnitude).
2. Viscoelastic creep refers to scenarios for which a polymer will permanently flow over time in response a constant applied stress.
1) When Viscoelastic stress relaxation occurs - step constant strain causes decreasing stress
2) When Viscoelastic creep occurs - step constant stress causes increasing strain