This section provides information on derivation of stiffness data.
The elastic modulus or modulus of elasticity, is a description of the tendancy for the timber to be deformed elastically (i.e., non-permanently) when a force is applied to it. The modulus of elasticity is defined as the slope of its stress-strain curve in the elastic deformation region.
The characteristic value of stiffness of most interest is the Young's modulus (E). This is frequently referred to as the modulus of elasticity, however it is one of several elastic moduli such as the bulk modulus and the shear modulus. Young's modulus is given by the mean of the slopes of the linear portion of the load / deflection plots of the test samples.
E-grader, for measuring stiffness, and proof loading, in bending as a joist
Source: Courtesy Timber Design Guide, 2007