Mechanical properties of materials

Created by

Summer Evans

Cards (24)

What is elastic deformation?
One where the object will return to its original shape once forces are removed
What is plastic deformation?
One where the object is permanently deformed, even once the forces have been removed
What is the condition for an object to experience tension?
There must be a pair of forces acting on the object in opposite directions, causing it to stretch
What are the conditions for an object to experience compression?
There must be a pair of forces, acting in opposite directions
What is the yield stress of an object?
The stress at and beyond the point which the object will undergo plastic deformation
What is the fracture stress of an object?
The stress that causes the material to break
What does it mean if an object is stiff?
It only produces a small extension per unit force
What does ductile mean?
It can be easily stretched
What does brittle mean?
It will undergo very little plastic deformation before a fracture occurs
What does tough mean?
It can absorb alot of energy before a fracture occurs
What law governs the extension of an elastic object?
Hookes law
What is hookes law?
The extension of an object is directly proportional to the force applied, up to the limit of proportionality, given that external conditions remain constant
Hookes law equation
F=kx
What is the unit for a spring constant?
$Nm^-1$
What is the limit of proportionality?
The point beyond which the object will no longer obey hookes law
What type of energy is stored when an object is stretched or compressed?
Elastic potential energy
What quantity is represented by the area under a force-extention graph?
The energy stored
What is the equation for the energy stored when an object is stretched?
$E=$ $(1/2 )kx^2$
What is stress?
The force per unit area applied to an object
What is strain?
The ratio of extension to original length
What is the youngs modulus of a material?
The ratio of stress ro strain
It is to measure a materials stiffness
What is the unit for stress
Pa pascals
What is the unit for youngs modulus?
Pascals
What was the aim for Rayleigh oil drop experiment?
It was designed to estimate the size of an atom