Formulation of a bondline element for modeling glued joints in wood

In this study, a computer model was developed to predict the elastic stresses and strains in an articulated wood member containing a thin bondline between adherents. This model used the finite element method with an innovative bondline element to characterize the thin layer of glue between members. This element was adopted from a published model for the behavior of massive rock formations containing thin veins of different materials. Comparisons were made between numerical results obtained in this study and theoretical predictions derived from certain problems with known closed-form solutions. Very close agreement between numerical and theoretical results were found in all problems. Also, numerical predictions were compared to experimental data obtained from instrumented tests of small wood members. Once again, good agreement between numerical and experimental results was found. In addition to verification studies, parameter studies were conducted to determine the numerical stresses in step, scarf, and finger joints in wood and an isotropic material with similar stiffness.