Multi-stage operation of single-lap hybrid joints constructed using a 3D-printed polymer with aluminium adherends subjected to uniaxial tensile test

Abstract

This paper presents the results of laboratory tests for single-lap hybrid joints. The specimens used a mechanical joint of the mortise-and-tenon type and a double-sided Very High Bonding (VHB) 5925 adhesive tape with a thickness of 0.6 mm. The mechanical joint is responsible for increased stiffness and strength, and the adhesive joint is responsible for significant energy absorption. One of the adherends, along with the tenon, was made by 3D printing from Z-ABS material. The other adherends were made from 2 mm thick aluminium and had a 19 mm diameter hole. The specimens were made in three groups: A, B, and C, differing in tenon design in such a way as to achieve multi-stage operation by gradually damaging the mechanical joint. They were subjected to static uniaxial tensile tests on an MTS 25 kN testing machine. During the tests, strain observations were made using the “Aramis” Digital Image Correlation (DIC) system. Analysis of force-displacement diagrams has shown that one to four stages of joint damage are possible, which is new in the world literature. A maximum increase in damage force of 185.4 % and 17.8 % for absorbed energy was achieved compared to the reference adhesive joint. In addition to contributing to the development of the field of hybrid joints, the results of the research can also be used in practice to design safety joints for example, in the automotive or aerospace industries, where after the maximum force is reached, the joint can continue to work and be integral even under relatively large displacements.