The research objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) award is to create a fundamental understanding of the Magnetic Pulsed Welding (MPW) process through a collaboration with an industrial partner Magneform and UNH faculty members from Mechanical Engineering, Physics, and Materials Science. While MPW has been used as a process for decades, the process is typically implemented based on experience and trial and error experimentation. The tasks of the proposed research are to experimentally investigate axisymmetric MPW joints including measurement of the deformation; to conduct materials testing of both the interface of the weld and the mechanical properties of the final joint; to model the process with respect to the electromagnetics, thermomechanical effects (which will allow for phase transformation), and wave formation at the interface of the weld; and to optimize the process parameters based on the experimental and modeling efforts.
If successful, the results of this research will benefit society at large through reduced weight of structures as dissimilar metals will be effectively welded and thus lower weight components will be located in non-strength critical areas. In addition, this research will add significantly to the modeling and materials characterization during high rate deformation and impact conditions, such as electromagnetic forming, ballistic impact, etc. Collaborating with Magneform offers several advantages including the broad dissemination of the results to industry. Graduate students will benefit from the interdisciplinary nature of the research and incorporation of results into several courses. Finally, Research Experience for Teachers participants will be involved in the research and will create modules for high school classrooms based on the Physics and magnetism aspects of the project. This high rate deformation process will capture the attention and imagination of high school students and potentially attract individuals from underrepresented groups to the project.
This project is jointly funded by the Materials Processing & Manufacturing (MPM) Program, of the Civil, Mechanical, and Manufacturing Innovation (CMMI) Division,the Thermal Transport Processes (TTP) Program, of the Chemical, Bioengineering, Environmental, and Transport Systems (CBET) Division and, the Grant Opportunity for Academic Liaison with Industry (GOALI) Program, of the Industrical Innovation and Partnerships (IIP)Divison, all within the Directorate for Engineering (ENG).
The goal of this research was to create a better fundamental understanding of the Magnetic Pulsed Welding (MPW) process through modeling, simulation, and experimental efforts. MPW will allow the joining of dissimilar metals which will enable significant light weighting to occur for end-product applications across many industrial sectors. In this technology, a capacitor bank is charged with electrical energy (on the order of 10 kJ) which is quickly dissipated into a coil to create a magnetic field. Any non-constrained metal in proximity to the coil will be launched at a high velocity (on the order of 100 m/s) deforming the material. If another stationary workpiece is impacted, a solid state weld is created. A wavy interface pattern phenomenon is observed during MPW if sufficient pressures and velocities are achieved for the given material combination. First, an analytical model (Thibaudeau and Kinsey, 2013) was created for a flat sheet uniform pressure coil application to predict velocities and pressures. The model was validated experimentally for various materials and sheet thicknesses. The threshold where the magnetic field penetrated through the thickness of the sheet metal thus preventing an effective process was identified. Also, in order to measure the velocity in a process, a fiber optic sensor which is an order of magnitude less expensive than the laser based method typically used was demonstrated (Turner et al., 2013). As for the interface phenomenon observed, a stability analysis showed that the shear velocity differential between moving and stationary sheets could create the wavy pattern during MPW (Nassiri et al, 2013). This provides a fundamental understanding of this mechanism which is observed in fluid dynamics applications such as cloud formations. Numerical simulations also indicated a wavy pattern was feasible based on solid mechanics principles. Finally, the improved formability during MPW was shown not to be caused by an electroplastic effect (Kinsey et al, 2013). The PI was also involved in a state-of-the-art paper in this technology area during the course of the project (Psyk et al., 2011). One Ph.D. student, three Master’s degree students, and four undergraduate students conducted this research and received extensive educational training. Several broader impacts were created through this multidisciplinary (including engineering, manufacturing, physics, and materials science) research. First, the results of this project benefited society at large through reduced weight of structures from dissimilar metals joining, thus allowing lower weight components to be located in non-strength critical areas. Also, the undergraduate and graduate students benefited from the integration of research results into course materials and collaborations with industry. In addition, this project added significantly to other research areas such as electroplasticity and modeling during high rate deformation and impact conditions. Finally, several Research Experience for Undergraduates and Research Experience for Teachers participants were involved in the work thus extending the educational benefits, including outreach to K-12 education due to the physics and magnetism aspects of the research. This high rate deformation process is able to capture the attention and imagination of high school students and potentially attract individuals from underrepresented groups to the science, technology, engineering and mathematics (STEM) disciplines.
