Material Properties 3 Flashcards
True or False? A viscous material deforms slowly when exposed to an external force.
True
True or False? An elastic material will return to its original configuration when the external force is removed.
True
True or False? A viscoelastic material displays history-dependant mechanics.
True
There are three main characteristics of a viscoelastic material. What are they?
Hysteresis
Stress-relaxation
Creep
What is Hysteresis?
Hysteresis is the dependence of the state of a system on its history.
The unloading curve is different from
the loading curve.
During unloading, a given amount
of stress produces greater deformation,
than the loading phase.
What is stress-relaxation?
Stress-relaxation describes the continued reduction in stress, despite constant
deformation.
Stress-relaxation is a time-dependant
response.
A material held at a constant strain will
require less stress to keep it there with time.
What is creep?
The creep phenomenon describes the continued deformation of a viscoelastic material after the applied force has reached a constant state.
A fixed amount of stress causes
deformation to increase over time.
This response is non-linear
True or False? Viscoelasticity is a critical property of the dermis
True
True or False? Ageing decreases the viscoelastic properties of skin
True
Are red blood cells viscoelastic?
Yes. Red blood cells (RBCs) play a pivotal role in oxygen delivery and travel through our circulatory system in blood. However, the diameter of RBCs is larger than that of the capillaries in the microcirculation.
RBCs display viscoelastic properties (deformation) to travel through capillaries.
Is Bone viscoelastic?
Bone meets the criteria for viscoelastic behaviour when it receives an applied force (stress) at different speeds
When a bone receives stress over a longer period
of time, it is more prone to fracture and breaks
