Yield stress, proof stress, toughness, Young's modulus, Hooke's law.
* "Stress is proportional to strain up to the PROPORTIONAL LIMIT (1)"
* This means that any increase in stress will bring about a proportional increase in strain up to the proportional limit.
* Written mathematically, the formula of Hooke's Law is:
* E is a constant. (Young's Modulus[see below])
* σ is stress (Pa)
* ε is strain
* Young's Modulus is a measure of the stiffness of a material.
* It is also known as the Modulus of Stiffness/Elasticity
* This is the constant that is represented in Hooke's Law (see above)
* This is when an increase in stress no longer has a linear relationship with an increase in strain.
* Sometimes this is known as the elastic limit.
* This is the ability of a material to retain its shape after being deformed.
* It can be found through the area under the curve up to the proportional limit.
* This is the Stress Value at the Progressive Yield Point (3).
* This is when there is no relationship between an increase in stress and an increase in strain.
* Is a useful value as the UTS point occurs after some deformation where this only begins to deform.
* An approximation for the Yield point/Elastic limit for materials that don't have a definite one due to their structure.
* To find the approximation, a tangent is produced from the Proportional Limit. The points of intersection between the graph and the tangent defines the Proof Stress of the material.
* The line may be moved slightly to accommodate for certain materials.
* Examples are 0.1%/0.2% Proof Stress, where the tangent is produced from a point slightly (0.001) to the right of the Proportional Limit.
* "A material's ability to absorb energy"
* This is sometimes known as impact strength.
* This can be found by...