Materials (M3) Flashcards
Polymeric
A material comprised of long-chain molecules such as rubber which may show large strains
Brittle
Property of a material that does not show plastic deformation and deformation very little if at all under high stress
Ductile
Property of a material that has a large plastic region in a stress-strain graph so can be drawn into thin wires
Strong
A material with a large value for the ultimate tensile strength
Tensile stress
The force per unit cross-sectional area
Unit: Pascals (Pa) or Nm^-2
Tensile strain
Extension per unit length
No units (dimensionless)
Often expressed as a percentage
Young’s modulus
The ratio of tensile stress to tensile strain when they are directly proportional to each other
Unit: Pascals (Pa) or Nm^-2
Limit of proportionality
The value of stress or force beyond which stress is no longer directly proportional to strain
Yield point
A point on a stress-strain graph after which the deformation is no longer entirely elastic
Ultimate tensile strength
The maximum stress that a material can withstand before it breaks
Tensile force
Equal and opposite forces acting on a material to stretch it
Compressive force
Two or more forces together that reduce the length or volume of an object
Elastic limit
The value of stress or force beyond which elastic deformation becomes plastic deformation and the material or onject will no longer return to its original shape and size when the force is removed
Elastic deformation
Average change in the shape of an object due to a compressive or tensile force - removal of force will return the object to its original shape and size (no permanent strain)
Plastic deformation
An irreversible change in the shape of an object due to a compressive or tensile force. Removal of the force produces a permanent deformation
