Elasticity implies that deformations produced by low stress
below the proportional limit are completely recoverable
after loads are removed. When loaded to stress levels above
the proportional limit, plastic deformation or failure occurs.
Typically, the stress–strain curve for wood-based composites is linear below the proportional limit. The slope of the
linear curve is the MOE. In compression or tensile tests, this
slope is sometime referred to as Young’s modulus to differentiate it from bending MOE. Bending MOE is a measure
of the resistance to bending deflection, which is relative to
the stiffness. Young’s modulus is a measure of resistance
to elongation or shortening of a member under tension or
compression. The procedure to determine MOE is fully described in ASTM D 1037 for fiber- and particle-based panel
products, ASTM D 3043 for structural wood-based panels,
ASTM D 5456 for structural composite lumber products,
ASTM D 7031 for wood–plastic composites, and ASTM D
7341 for glulam products.
