Proof-of-concept of magnetic pulse disassembly of adhesively bonded Aluminum 2017 T4-MARS 300 specimen

The design of hybrid structures in order to correctly manage the disassembly of their subcomponents has emerged as a significant demand of various industries, regarding end-of-life, maintenance or recycling purposes. Especially, laminate structures are widespread and their disassembly, without damaging layers, and with a controlled amount of energy, is a challenging task. This study presents a proof-of-concept of Magnetic Pulse Disassembly (MPD) of adhesively bonded aluminum–steel assemblies. The GEPI pulse system available at CEA Gramat, was selected as a tunable source of energy to evaluate the ability of short-duration magnetic pulses, to debond millimeter-thick assemblies on the principle of dynamic adhesion tests. The specimens, composed of aluminum 2017 T4 and MARS 300 steel bonded by a thin epoxy adhesive, were subjected to GEPI pulses and the free surface was monitored with heterodyne laser velocimetry. Ten interfacial assembly conditions were selected, including partially bonded (localized adhesive spots) and fully bonded assemblies, in which adhesive failure was observed at the interface, with various fracture patterns depending on the bonding configuration. To interpret the experimental results, various estimates of the interface’s fracture strength are constructed based on extensions of Novikov’s basic criterion applied to multi-material assemblies in the context of time continuous loading. The proof-of-concept is here validated, on the one hand regarding the ability to correctly predict the measured backface velocity up to the onset of interfacial failure, and on the other hand via the ability to compute the interface’s fracture strength of the assembly from the measurements. The proposed approach introduces a methodology of design for disassembly under magnetic pulse loading. It also opens new perspectives for reversible joining technologies and end-of-life recycling applications.