Mechanical Properties of Dahurian Larch Wood under Cyclic Loading: Experiments and Constitutive Model

This article presents a study on the mechanical properties and constitutive model of Dahurian larch wood under parallel-to-grain (ParG) and perpendicular-to-grain (PerG) cyclic loading. A total of twenty-four dog-bone specimens were designed and prepared. Failure modes, stress-strain curves, elastic moduli under monotonic loading, and unloading/reloading moduli under cyclic loading were analyzed. Results indicated that the tensile and compressive envelope curves of wood under cyclic loading are similar to the monotonic stress-strain curves. The unloading and reverse reloading stiffness of wood are significantly degraded in both material directions. Furthermore, a constitutive model that is capable of considering the degradation of cyclic compression unloading stiffness and the change in reverse compression (tension) stiffness after tension (compression) unloading was proposed. A comprehensive comparison with test results was conducted, and they are in good agreement. Thus, the correctness of the proposed constitutive model is verified.