Definitions for "Modulus of Rupture"
Keywords:  rupture, torsion, bend, torque, stress
When the material is difficult to grip (as is a ceramic), its strength can be measured in bending. The modulus of rupture (MOR) is the maximum surface stress in a bent beam at the instant of failure. One might expect this to be exactly the same as the strength measured in tension, but it is always larger (by a factor of about 1.3) because the volume subjected to this maximum stress is small, and the probability of a large flaw lying in the highly stressed region is also small. (In tension all flaws see the maximum stress.) The MOR strictly only applies to brittle materials. For ductile materials, the MOR entry in the database is the ultimate strength.
Nominal stress at fracture in a bend test or torsion test. In bending, the modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar section modulus.
The unit stress at which a piece fails.