Studies on effect of surface profiles and field shaper geometries on electromagnetic crimping of tubes on rods
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The electromagnetic crimping (EMC) is a high energy, high strain rate, high velocity and green mechanical joining technique. Joining of dissimilar materials was very difficult because their physiochemical properties are seldom compatible or similar. Therefore, this type of solid-state joining technique can be an alternative for joining dissimilar materials.Numerical studies as well as experimental work were carried out for EMC process. Numerical simulations were carried out for finding out the optimized parameters for crimping and then experiments were conducted on the optimized parameters. The results obtained from the simulations revealed that for the successful crimping minimum value of collision velocity, plastic strain, electromagnetic pressure, and stand-off distance must be maintained.To increase the strength of the joint profiles were created on the base rod. There were three types of profiles created threaded, knurled, and plain profile. The influence of these profiles on the joint strength, surface roughness and microstructure of the joint were analyzed and compared. Mechanical tests such as compression-shear test and a pull-out test revealed that threaded surface profile on the steel rod gives better strength in comparison to the other two profiles. Along the circumference of the Copper-Steel composite rod, the microstructure images of the joints were analyzed and it was found that there was a negligible gap along the circumference of the sample crimped at 5.3 kJ of discharge energy with a plain profile. This study has been carried out with two different combinations of materials such as aluminum-steel and Copper-Steel. For the Copper-Steel combination of materials, tapered field shaper was used whereas for aluminum-steel combination of materials stepped field shaper was used.
Supervisor: Sachin D. Kore