Question

What is "Double Subscript Notation for Stresses"?

Answer 1

Stress is a tensor quantity and tensor quantities require 2 sub scripts for their complete definition. 1 subscript defines force and the other area.

Step-by-step explanation:

Stress at a point is defined as follows

`\sigma =\lim_(\Delta a\rightarrow 0)\frac{\overrightarrow{\Delta F}}{\Delta A}`

In the expression above in addition to the direction of force F we also need to define orientation of the area that we choose in defining the limit of the quantity on right hand side of the expression above hence we get a dobule subscript notation in stress at a point. 1 subscript defines force and the other area.