Papyrus 75

The bending stiffness is equal to the product of the elastic modulus $E$ and the area moment of inertia $I$ of the beam cross-section about the axis of interest. In other words, the bending stiffness is $EI$. According to elementary beam theory, the relationship between the applied bending moment $M$ and the resulting curvature $\kappa$ of the beam is

$M=EI\kappa =EI\frac{{\mathrm{d}}^{2}w}{\mathrm{d}{x}^2}$

where $w$ is the deflection of the beam and $x$ the coordinate. In literature the above definition is sometimes used with a minus sign depending on convention.

Bending Stiffness in beams is also known as Flexural Rigidity.

See also

• Beam theory
• Bending
• Applied mechanics

External links

• Efunda's beam calculator