Mechanical strength of adhesively bonded joints using polymeric additive manufacturing

Abstract

This paper investigates the combined use of one of the most widespread additive manufacturing techniques, fused deposition molding, with polymeric materials and structural adhesive. The aim is twofold: first, to enhance the adhesive performance exploiting the capability of the additive manufacturing to tailor the bonding surface of the adherend, and second to overcome one of the main limitations of 3D printing, i.e. the quite small printing volume, by means of adhesive bonding. Bonding multiple parts together without loss of performance could open new possibilities for this technology. The present research analyzes, by using a Design of Experiment technique, a wide set of single lap joints with two adhesives and seven different surface morphologies. The results highlight that the adhesive bonding does not undermine the load carrying capacity of the joints as well as their stiffness, and, in some cases, it causes a slight improvement of the peak force. The morphology of the surface plays only a small role in the performance of the system, since it cannot provide a strong mechanical interlocking of the parts due to peel stresses and because of the predominant effect of stress concentrations at the corners, which cause substrate failure.