Materials Flashcards
What is density?
A measure of the ‘compactness’ of a substance.
What is Hooke’s law?
The force of the load is proportional to the extension of the wire.
What is the limit of proportionality?
Where Hooke’s law no longer applies.
What is the elastic limit?
A point where the object will become permanently stretched and will not return to its original shape.
What is tensile stress?
Force applied per unit cross-sectional area.
What is tensile strain?
Ratio of extension to natural length.
What is elastic strain energy?
Area under a force extension graph and shown to be the work done in terms of energy stored in the material when stretched.
What is the Young’s Modulus of a material?
A measure of the stiffness of a material.
What is the yield point?
Point at which we observe a noticeably large change in length.
What is breaking stress?
The value of stress at which the material will break apart, this value will depend on the conditions of the material. (its temperature)
What is elastic deformation?
A temporary change in the form of an object due to an applied stress, which reverts to its original shape once the stress is removed.
What is plastic deformation?
A permanent change in the form of an object due to an applied stress, which does not revert to its original shape once the stress is removed.
What is a brittle material?
A material that will only elastically deform before stress gets too much to where the material will suddenly snap.
i.e doesn’t plastically deform
What is a ductile material?
A material that has a large plastic region
What is necking?
Where the material can no longer withstand the maximum stress and the strain in the specimen rapidly increases.
