3.4 - 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
What is the difference between Elastic and Plastic Deformation?
In elastic deformation, the shape returns back to its original shape
In plastic deformation, the shape does not return to its original shape
What is Hooke’s Law?
F=kx where:
F is the Force
x is the extension
k is the force constant
The law states that the extension of an object is proportional to the force that causes it, provided that the elastic limit is not exceeded
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 Stress?
The force per unit cross-sectional area. It has units of Nm^-2 or Pa
What is Strain?
Extension per unit length. It has no units and is therefore dimensionless
