Shear Strength in Principal Plane of Wood

Abstract

In this study, the writers used Tsai and Wu's tensor polynomial theory to rederive a formula originally derived by Cowin for shear strength variation in a plane of material symmetry of orthotropic materials. Experimental work was then performed (based on a method by Arcan, Hashin, and Voloshin) on Sitka spruce specimens to verify the formula. The theory and experiment agreed closely. When the angle between shear force and grain on the longitudinal‐tangential plane increased from 0‐30° shear strength decreased more than 43%. Engineers should take this relationship into account when designing wood structural members.