Stress

Stress, abbreviated as \(\sigma \) (Greek symbol sigma), is the force per unit area of cross-section.  The maximum stress of a material before it breaks is called breaking stress or ultimate tensial stress.

 

Stress formulas

\(\large{ \sigma = \frac{F}{A_c} }\)
\(\large{ \sigma = \lambda \; \epsilon }\)	(elastic modulus)
\(\large{ \sigma = E \; \epsilon }\)	(Young's modulus)

Where:

\(\large{ \sigma }\)  (Greek symbol sigma) = stress

\(\large{ A_c }\) = area cross-section

\(\large{ \lambda }\)  (Greek symbol lambda) = elastic modulus

\(\large{ F }\) = force

\(\large{ \epsilon }\)  (Greek symbol epsilon) = strain

\(\large{ E }\) = Young's modulus