Calculation for Stress-strain carves:
After reaching point D, if bar is strained further, a local reduction in cross section occurs in gauge length (that is, formation of neck). At this neck stress increases with decrease in area at constant load, till failure take place. Point F is called as 'rupture point. Note that all the stresses are based on original area of cross section in drawing curve of the given figure. 1. Yield strength = where (original area ) 2. Ultimate strength = 3. % Elongation =
where LF = Final length of specimen
L0 = Original length of specimen 4. % Reduction in area =
where AF = Final area of cross section
A0 = Original area of cross section
5. Young's modulus of elasticity, E =
From the figure clastic limit is up to point B.