# Shape Factor

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Shape factor, is a dimensionless number that is abbreviated as $$k$$.  In structural it is the strength of the shape no matter the scale for a given load, bending, torsion, or twisting.

### Shape Factor Formula

$$\large{ k = \frac{Z}{S} }$$

Where:

$$\large{ k }$$ = shape factor

$$\large{ S }$$  = elastic section modulus

$$\large{ Z }$$ = plastic section modulus