Strength of Materials

2.4 PRINCIPAL STRESSES AND STRAINS

2.4.1 Principal Stresses

Let us consider all the planes passing through a point and locate such a plane on which there are no shear stresses. There are atleast three such planes at a point on which there are no shear stresses. The additional characteristics of these is that they are mutually perpendicular to each other (Figure 2.8).

 

 

Fig. 2.8 Principal stresses on orthogonal planes.

 

On these planes, there are no shear stresses acting but only normal stresses. These normal stresses are called as principal stresses.

Thus, principal stress may be defined as a normal stress acting on a plane wherein there ...