Experimental and Numerical Study on Glass Stresses and Shear Deformation of Long Adhesive Joints in Timber-Glass Composites

Abstract

This study assesses the shear strength of long adhesive joints on mid-size specimens to resemble virtually a life-size situation in a typical timber-glass composite element. The specimens comprise a rectangular glass pane which is adhesively bonded along its vertical edges onto timber posts. The study focuses on three different adhesives ranging from flexible silicones to viscoplastic epoxies with a high stiffness. In the experiment, the adhesive joints are stressed in longitudinal shear and loaded until failure.The experiment is simulated using a numerical model of the specimen. The joint is described by basic material models taking into account linear or bilinear behavior of the adhesive material. The corresponding material properties of the adhesives were derived from uniaxial tensile tests on the cured adhesive. The stiff adhesive causes high stress concentrations close to the edge where the load is applied. More flexible joints lead to a more homogenous distribution since the shear loading result in higher compressive stresses in the lower parts of the glass pane. Finally, we compare the results from the experiment and the numerical simulation by means of glass stresses and shear deformation of the adhesive bond line. It can be shown that bilinear constitutive equations are an adequate approximation of the adhesive to determine the glass stresses in the pane. However, the deformations could not be reproduced for all adhesives in the same accuracy than the stresses.