Calculate flexural modulus from bending test data, stress and strain, or an illustrative material stiffness reference, with results in MPa, GPa, ksi, and psi.

Simply supported rectangular specimen with a central load.

Use small-deflection, linear-elastic bending data. Material examples are illustrative stiffness references, not measured flexural properties or design values.

Examples fill span, width and thickness; verify the actual specimen and test requirements.

Flexural Modulus Formula

The following ratio gives the origin-to-point flexural secant modulus. It equals the elastic modulus for appropriately zeroed linear-elastic data:

E = (ฯƒ) / (ฮต)

Variables:

  • E is the flexural modulus (MPa)
  • ฯƒ is the stress (MPa)
  • ฮต is the strain (unitless)

Divide corresponding flexural stress by strain to calculate the secant modulus. Tangent or chord modulus requires the appropriate stressโ€“strain slope.

What is Flexural Modulus?

Flexural modulus, also known as the modulus of elasticity in bending, is a measure of a material's stiffness or resistance to flexural deformation. It is defined as the ratio of stress to strain in flexural deformation, or the tendency for a material to resist bending. It is an important parameter in engineering and materials science, particularly in the design and analysis of materials that will undergo bending stresses.

How to Calculate Flexural Modulus?

The following steps outline how to calculate the Flexural Modulus:

  1. First, determine the stress (ฯƒ) in the material under flexural load, measured in megapascals (MPa).
  2. Next, determine the strain (ฮต) in the material, which is a unitless value representing the deformation per unit length.
  3. Use the formula E = ฯƒ / ฮต to calculate the Flexural Modulus (E).
  4. Finally, enter the values of stress and strain into the calculator to find the Flexural Modulus.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Stress (ฯƒ) = 120 MPa

Strain (ฮต) = 0.005 (unitless)