Stress and Strain

Vital Equations

stress=force/area

strain=extension/natural length

Young's Modulus E=stress/strain.

Elastic Potential Energy E=1/2*force*change in length <- can be found from the area underneath a force against extension graph.

Characteristics of a stress strain curve:

- Limit of proportionality, the point up to which stress and strain are proportional to each other (obeys Hooke's Law)

- Elastic Limit, material will return to its original position being stretched up to this point, any further and it will permanently deform. When this happens it enters the plastic region.

- Yield Point, after this point when a little amount of load is added there is a great extension.

- Breaking Stress, the point at which the material ruptures (AKA Rupture Point).