Experimental and numerical analysis of 3D-printed single-lap joints with mixed PLA/ABS adherents under tensile loading

This study investigates the mechanical performance of adhesively bonded single-lap joints (SLJs) fabricated using various mixtures of polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM). The adherents consisted of pure PLA, PLA80%-ABS20%, PLA65%-ABS35%, PLA50%-ABS50%, PLA35%-ABS65%, PLA20%-ABS80%, and pure ABS. In order to manufacture the specimens, a custom-designed double-extruder system was used, allowing controlled filament feeding and in-nozzle mixing based on the desired PLA-ABS ratio. Tensile tests were conducted to assess the mechanical behavior of the SLJs. Additionally, finite element (FE) simulations incorporating the mechanical properties of the adherents were developed to model the joint performance. The adherent properties were experimentally obtained using tensile tests on 3D-printed dogbone specimens. The experimental results showed that increasing ABS content enhanced adhesion to the epoxy adhesive, with the failure mode shifting from adhesive failure in pure PLA specimens to adherent failure in pure ABS specimens. A strong correlation was observed between the FE simulations and experimental data, highlighting the accuracy of the modeling approach. These findings emphasize the potential of tailoring PLA-ABS compositions to optimize the mechanical performance of bonded joints for various engineering applications.