Materials Science & Technology Flashcards

Which foam material is most commonly used as the soft interface or cosmetic cover in prosthetic devices due to its light weight and ease of carving?

Answer: Polyurethane foam

Polyurethane foam is widely used for prosthetic cosmetic covers because it is lightweight, easily carved to shape, and can be covered with a cosmetic stocking.

The modulus of elasticity (Young's modulus) describes which material property?

Answer: Stiffness — the ratio of stress to strain in the elastic region

Young's modulus defines how stiff a material is by relating the applied stress to the resulting elastic strain; higher modulus = stiffer material.

Dynamic elastic response (energy-storing) prosthetic feet store energy primarily in which component?

Answer: Carbon fiber keel/blade

The carbon fiber keel deflects under load to store strain energy, which is released during push-off to assist propulsion.

Vacuum-assisted socket suspension (VASS) improves suspension primarily by:

Answer: Creating negative pressure between the liner and socket wall

VASS uses a pump to evacuate air between the liner and socket, creating consistent negative pressure that improves suspension and proprioception.

Which of the following best describes the term 'anisotropy' as applied to carbon fiber composites in O&P?

Answer: Mechanical properties vary depending on the direction of applied load

Anisotropic materials like carbon fiber composites have direction-dependent properties; they are very stiff along fiber orientation but much weaker perpendicular to fibers.

Which coating or surface treatment is applied to the inside of a prosthetic socket to reduce friction and improve skin health at the residual limb interface?

Answer: Smooth thermoplastic liner or silicone coating

Smooth thermoplastic inner surfaces or silicone-coated sockets reduce shear forces and friction against the residual limb, protecting skin integrity.