# Definition of Principal stresses | Principal plane | Principal Axis

Saturday, March 3, 2012 14:39**Principal stresses :**

Principal stresses may be defined as

*” The extreme values of the normal stresses possible in the material.”*

These are the maximum normal stress and the minimum normal stress. Maximum normal stress is called major principal stress while minimum normal stress is called minor principal stress.

**Principal plane :**

Principal plane may be defined as

**” The plane on which normal stress attains its maximum and minimum value.”**

So these planes are also called as major principal plane and minor principal plane. The shear stress on principal plane is zero.

**Principal Axis :**

Principal axis may be defined as

**” The axis where moment of inertia is maximum or minimum and product of inertia is zero.”**

**Note :**

- Principal plane is the property of stress whereas principal axis is the property of moment of inertia. There is no relation between principal axis and principal plane.

sachin says:

February 16th, 2013 at 4:16 pm

detailed definition of principal stress