Eovations's mineral/thermoplastic composite has a modulus of
elasticity between 500,000 psi and 800,000 psi, but a modulus of
rupture of zero. It can flex extremely well, but does not have a
catastrophic failure mode. (Source: Eovations) @Ann: Okay,
apparently you learned some highly non-standard definitions.
According to Instron's glossary of materials testing, modulus of
rupture is synonymous with flexural strength. If you Google
"modulus of rupture," you'll see that this is the most commonly
used definition. Clearly, "the flexural strength is zero" would
not be a correct statement. The derivation of the most widely-
used modulus of rupture formula assumes that the material
deforms in a linear and elastic way, so the formula no longer
applies after the yield point. However, this doesn't mean that
"the modulus of rupture is zero"; it just means that the formula
no longer correctly predicts the stress. As far as "catastrophic
failure" goes, the most common definition seems to be "(sudden)
failure from which re