Materials Flashcards
What is density?
Mass per unit volume. The measure of the compactness of a material.
State Hooke’s law.
Extension is directly proportional to the force applied, given that environmental conditions are kept constant, and up until the limit of proportionality is reached.
What is the limit of proportionality?
The point after which Hooke’s law is no longer obeyed.
What is the elastic limit?
A point just after the limit of proportionality. Force applied after this point will deform the material plastically.
What is the spring constant, k?
The measure of the stiffness of the spring.
How do we calculate elastic strain energy?
Area under a force-extension graph. W=FScosθ
What is breaking stress?
The value of stress at which the material will break apart.
Ductile
Can undergo a large amount of plastic deformation before fracturing.
Brittle
Extends very little, and fractures at a low extension.
Plastic
Large amount of extension, especially beyond the elastic limit. Work done is dissipated as heat.
What is the ultimate tensile stress?
The highest point on a stress-strain graph, shows the maximum stress the material can withstand.