Materials Flashcards
What is elasticity?
The property of a body to resume its original shape or size once the deforming force or stress has been removed.
What is deformation?
The change in shape or size of an object. If the material returns to its original shape, then the deformation is elastic, if not it is plastic.
What does Hooke’s law state?
The extension of an object is proportional to the force that causes it, provided that the elastic limit is not exceeded.
What is given by the gradient and area of a graph of force against extension?
Gradient: Force constant, k
Area: Work done, W
What is stress?
Force per unit cross-sectional area.
What is strain?
Extension per unit length.
What is a ductile material?
A material that can be drawn into wires and will show plastic deformation under tensile stress before breaking.
What is a malleable material?
A material that can be hammered or beaten into flat sheets and will show extensive plastic deformation when subjected to compressive forces.
What is a brittle material?
A material that will break with little or no plastic deformation.
What is a hard material?
A material that will resist plastic deformation by surface indentation or scratching.
What is stiffness?
The ability of a material to resist a tensile force.
What is a polymeric material?
A material made of long chains of molecules (polymers).
What is ultimate tensile strength?
The maximum stress a material can withstand while being pulled or stretched before it falls or breaks.
