UC San Diego

Explosive welding is a field with a wide variety of applications of great value, such as corrosion resistant cladding and bi-metallic joints. It occupies a special place in the available metal joining techniques. Dissimilar metal welding is possible in metal pairings that don’t support other conventional bonds, and it can produce superior area welds regardless of the metal parts to be joined. The objectives of this dissertation were to further the understanding of explosive welding in general, as well as the empirical understanding of welding of Aluminum 6061-O, and to investigate the use of LS-DYNA’s Multi-Material Arbitrary Lagrangian-Eulerian formulation as a potential tool for the design of explosive welds. In the course of the work, the theory on formation of bond interfacial waves was identified as an area where there was not an apparent consensus, and this was addressed in light of both recent works and information from this study.

For this dissertation, an experimental program of explosive welding tests, mechanical weld verification, and metallurgical observation were undertaken in order to add to the data available for this type of welding. Nine different explosive welding tests were conducted covering four scenarios, which were combinations of different explosive thicknesses and flyer inclination angles. Tensile shear tests with digital image correlation were used to test the welds, and optical microscope, Scanning Electron Microscope, and Transmission Electron Microscope images were used to investigate the nature of the bond. The numerical investigation was conducted and compared to both experiment and initial modeling results.

The results reinforce the need for well-developed and material specific welding windows, adding additional data for the joining of Aluminum 6061-O. The endorsement of the continuous Kelvin-Helmholtz jet wake as the source of instability was supported with modeling results. The Multi-Material Arbitrary Lagrangian Eulerian modeling with Euler-Lagrange Coupling was demonstrated to yield results comparable to research codes for welding parameters, to be able to capture jetting, and provide meaningful temperature results. Bond interfacial waves were characterized with some success as well, concluding that this modeling technique is a viable means to assist in the design of explosive welds.