Modulus of Rupture, frequently abbreviated as MOR, (sometimes referred to as bending strength), is a measure of a specimen’s strength before rupture. It can be used to determine a wood species’ overall strength; unlike the modulus of elasticity, which measures the wood’s deflection, but not its ultimate strength. (That is to say, some species of wood will bow under stress, but not easily break.)

Modulus of rupture (MOR) testing

Modulus of rupture (MOR) testing

MOR is expressed in pounds-force per square inch (lbf/in2) or megapaschals (MPa). This number is given for wood that has been dried to a 12% moisture content, unless otherwise noted.

mor

In practical terms, the number itself isn’t all that meaningful, but it becomes useful to use in comparison with other woods. For instance, Hickory is known to have excellent strength properties among domestic species in the US, and has a MOR of 20,200 lbf/in2 (139.3 MPa). In comparison, Red Oak is another well-known wood used in cabinetry and furniture, and has a MOR of 14,300 lbf/in2 (98.6 MPa).