On a stressed body there are points on which shear stress is zero. These planes are known as:

Question

Question

This question was previously asked in

JKSSB JE CE 2015 Official Paper

Answer 1

Explanation

The maximum and minimum values of normal stresses occur on planes of zero shearing stress.

The maximum and minimum normal stresses are called the principal stresses, and the planes on which they act are called principal planes.

quesImage5082

If you look at the fig, A ( σ, 0) and B (0,0) are maximum and minimum stresses (i.e Principal stresses).

So, On a principal plane value of shear stress is zero.

Important Points

On a principal plane, shear stresses are zero and the vice-versa is not true. ( As on a plane of maximum shear stress normal stresses exist).