An anatomical explanation for visco-elastic and mechano-sorptive creep in wood, and effects of loading rate on strength

Abstract

For wood, it is widely known that the steady application of force, in either of the several possible stress modes, causes deformation which increases with time (creep). With any particular intensity of stress, it is well documented that the rate of creep varies significantly, according to whether the stress mode is in compression, bending, tension or shear. Additionally, it has been shown that the amount of creep tends to be considerably greater, if the moisture content of wood is reduced or cycled, than if it is constant (saturated or dry) during application of the force. However, the literature does not contain a broadly acceptable explanation for these phenomena.