Frictional & Rheological Properties of Biological Materials
Subtopic: Creep and stress relaxation in food materials
Question Statement:
Which of the following statements regarding viscoelastic behavior of biological products is/are TRUE?
Options:
(A) In a stress relaxation test, a constant strain is applied and the decay of stress is recorded over time
(B) In a creep compliance test, a constant stress is applied and deformation (strain) is recorded as a function of time
(C) The Maxwell model exhibits instantaneous elastic response followed by unbounded viscous flow under constant stress
(D) The Kelvin-Voigt model is capable of predicting instantaneous stress relaxation to zero
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
1. Stress relaxation holds strain $\epsilon = \epsilon_0$ and measures relaxing stress $\sigma(t)$ (A is true).
2. Creep holds stress $\sigma = \sigma_0$ and measures accumulating strain $\epsilon(t)$ (B is true).
3. In Maxwell model, series dashpot continuously flows under constant stress (C is true).
4. Kelvin-Voigt dashpot prevents instantaneous deformation, making it incapable of modeling stress relaxation (D is false).