Materials Flashcards
What is σ?
the force applied per unit
of cross-sectional area, tensile stress
What is Ɛ?
a ratio of the extension to the original length, tensile strain
Brittle
Object shows very little strain before reaching breaking stress.
Compression
The result of two coplanar forces acting into an object. Results in a reduction of length.
Ductile
Can undergo a large strain.
What is the limit of proportionality?
The point at which a material stops obeying Hooke’s law.
What is the elastic limit?
The point past which the material will be plastically deformed.
What is ultimate tensile strength?
The maximum stress a material can take before it breaks.
On a force-extension graph, what does the area represent?
Elastic Potential Energy
What is the expanded formula for E?
Fl/Ax, where l is unstretched length
Which graph do you plot for Young’s Modulus experiment?
Stress against strain, so that gradient = E and area = EPE per unit volume
What is the yield point?
the stress at which a large plastic deformation occurs without any extra load.
Stiff
difficult to stretch/compress, large E
Strong
High breaking stress.
With an oscillating spring displacement-time graph, where is maximum force and why?
At max. displacement because F=kx, max extension = max force.
