Answer to Question #200652 in Mechanics | Relativity for Master j

Question

Sketch a stress-strain graph for mild steel and identify the following points:

i. The proportional limit stress

ii. The yield stress

iii. The stress at the elastic limit

iv. The ultimate tensile stress

v. Also identify the elastic region and the plastic region on your graph

Answer 1

Proportional limit :-

Limit till which stress is Proportional to strain . Linear relationship. Slope of graph in this region is a constant and is the young’s modulus. Hookes law is obeyed here. Not the same as elastic limit. This occurs first in the stress strain curve.

Elastic limit: -

Limit within which body reaches original configuration on load removal. Slope of graph is not a constant. This is not the Proportional limit. This occurs after the Proportional limit.

Thus, there is a small region between elastic limit and Proportional limit.

Yield limit - Point which signifies the start of plastic deformation. But this does not signify the end of limit of elastic deformation. End of elastic limit is signified by elastic limit.

Thus, there is a small elasto plastic region between the elastic and yield limit where deformation is neither true elastic nor true plastic.

Resilience - Area under the stress strain curve within the proportionality limit (energy absorbed during the linear limit)

Proof resilience - Maximum energy that can be absorbed during the elastic limit , that is till the Proportional limit.

Proof stress - Stress corresponding to the Proportional limit.