Material Definitions Flashcards
Elastic Deformation
where a material returns to its original length when the force stretching/compressing it is removed
Plastic Deformation
where a material DOES NOT go back to its orignial length after the force strectvhing/compressing it is removed - it has a PERMANENT CHANGE in length
Limit of Proportionality
the limit beyond which when a wire/spring is stretched, its extension is NO LONGER PROPORTIONAL to the force
Elastic Limit
the maximum stress that can be applied to a material without causing it permanent extension
Hooke’s Law
the extension is directly proportional to the (tensile) force applied, up to the limit of proportionality
Tensile Stress
the force applied per unit cross-sectional area when a material is stretched
Tensile Strain
extension produced per unit length
Young’s Modulus
tensile stress/tensile strain
for stresses up to the limit of proportionality
Yield Point
point at which the stress in a wire suddenly drops when the wire is subjected to increasing strain
Breaking Stress (Ultimate Tensile Stress)
the maximum tensile stress a material can withstand before it breaks
Stiffness
A measure of how difficult it is to change the size/shape of a material, a stiff material requires a large amount of energy to produce a small change in shape.
Brittle
material breaks without any plastic deformation
Strength
measure of the stress required to break a material
Strong
requires a large stress to break - with a large UTS
Weak
requires a small stress to break - small UTS
