Flexural strength.html

This article needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2008)

The introduction to this article provides insufficient context for those unfamiliar with the subject.
Please help improve the article with a good introductory style. (November 2008)

Flexural strength, also known as modulus of rupture, bend strength, or fracture strength,^{dubious – discuss} is measured in terms of stress, and thus is expressed in pascals (Pa) in the SI system. The value represents the highest stress experienced within the material at its moment of rupture. In a bending test, the highest stress is reached on the surface of the sample.

For a rectangular sample under a load in a 3 pt bend setup: $\sigma = \frac{3FL}{2bd^2}$

F is the load (force) at the fracture point
L is the length of the support span
b is width
d is thickness

For a rectangular sample under a load in a 4 pt bend setup where the loading span is 1/3 of the support span: $\sigma = \frac{FL}{bd^2}$

F is the load (force) at the fracture point
L is the length of the support (outer) span
b is width
d is thickness

For the 4 pt bend setup, if the loading span is 1/2 of the support span: $\sigma = \frac{3FL}{4bd^2}$

If the loading span is neither 1/3 or 1/2 the support span for the 4 pt bend setup: $\sigma = \frac{3F(L-L_i)}{2bd^2}$

L_i is the length of the loading (inner) span

References

J. M. Hodgkinson (2000). Mechanical Testing of Advanced Fibre Composites. Cambridge: Woodhead Publishing, Ltd. p. 132–133.

Flexural strength.html

See also

References