Research
In my Ph.D. work, we have successfully established the feasibility of novel electromagnetic forming and perforation (EMFP) of tube process. Along with the experimental study, we have developed FE based simulation algorithms to simulate the EMFP process. These FE based simulations are used to study the material movement and material behavior at a high strain rate. The developed model shows almost 96% agreement with experimental results. Further comparison study is carried out to identify the advantages of electromagnetic perforation over conventional perforation techniques. The comparison study concluded that the with electromagnetic perforation, better quality of sheared edge (burr less) can be obtained, In general, the good agreement of FEA results with findings in the experiment shows the prediction capability of developed numerical models. Overall, the study concluded that the EM techniques are advantageous over conventional processes. Finally, by modifying the parameters as per requirement in this study, one can commercialize these applications of EM forming processes.
Nowadays, I am looking for a specific applications of developed EMFP of tube process as deformed perforated tube has many applications in the automobile and oil industries.
Electromagnetic Forming
The process is also called the magnetic pulse forming process. To study the principle of electromagnetic forming, consider a tubular workpiece. The coil is placed inside the workpiece. In this process, a high charging voltage is supplied for a brief timeframe to a bank of capacitors connected in parallel (The amount of electrical energy stored in the bank can be increased either by adding capacitors to the bank or by increasing the voltage). When the charging is completed, which takes little time, a high voltage switch triggers the stored electrical energy through the coil. A high-intensity magnetic field is established, which induces eddy current into the conductive workpiece, resulting in the establishment of another magnetic field. There would be a robust Lorentz force between the coil and the metal plate. Because of Lenz’s Law, the magnetic fields created within the metal workpiece and work coil actively repel each other. The coil creates a strong magnetic force that easily overcomes the yield strength of the metal workpiece, causing permanent deformation.
Electromagnetic Forming and Perforation of Tubes
Electromagnetic forming and perforation (EMFP) of tubes is the application of electromagnetic forming process. In the conventional manufacturing of perforated tubes, the metal sheet is first perforated by blanking, then rolled and welded into the tube. This process is time-consuming as it involves multiple operations, and also it leads to some weld defects. To overcome this problem, a novel EMFP technique is developed where simultaneous expansion and perforation of the tube can be possible. This will result in near net shape product with faster rate of production. The electromagnetic perforation setup comprises high voltage discharge unit, coils, punches and specially designed die. The coil is used as a tool to use EM field; die is used for getting the desired shape and perforation is done by using a punch. The working principle is same as that of electromagnetic forming process. Punches were located around the tube using a die. While the expansion of tube, it gets perforated by the punches.
Schematic representation of electromagnetic forming and perforation of tubes
Experimental results show that the concave punches are more suitable for perforation as complete removal of blank took place, which results in clear perforation. The process involves high strain rates, high velocities etc. and it is difficult to find out the parameters, material movement experimentally. To study theses parameters and material movement, The FE analysis is carried out for EMFP process. A very good agreement between the numerical and experimental results is established. Through simulation one can easily visualize the process For the comparison of conventional (low strain rate) and electromagnetic (high strain rate) shearing, a setup for quasi-static die-less perforation is developed, and experiments are carried out. Here, we have studied different sheared edge zones for EM as well as Quasistatic forming with both pointed and concave punches. The results obtained during this study show the capability of electromagnetic perforation to obtain perforated holes with better edge surface finish and material properties over the quasi-static perforation process.
Electromagnetic Forming of Muffler Tubes
In traditional manufacturing techniques of muffler tubes, the metal sheet is formed by conventional practices, then it is rolled and welded into desired shape. The welded zone in the muffler tube is more brittle, and it has less fatigue strength, which may result in failure. In this part of work, experiments are carried out on Al6061 tubes, which results in a single piece of component of the desired shape (muffler), hence it eliminates the weld zone and the working life of muffler may extend. In conventional muffler the tube used is steel and it adds to the weight of automobile. Use of aluminium is difficult due to poorer formability at low strain rate. EM forming being high strain rate can form Al muffler tube and reduce the weight of the automobile. The FE analysis is carried out for both EM forming of muffler tube and EMFP process. The coupled and non-coupled simulation algorithms are developed and used for the FE analysis. In FEA of EM forming of muffler tube, a coupled simulation method is used, and a good agreement with deformation obtained experimental results is observed.
EM forming of muffler 1.wmvElectromagnetic Forming of Tube
Electromagnetic forming and perforation.wmvFE-Based Simulation of Electromagnetic Forming and Perforation of Tube
Em forming of muffler main.wmvFE-Based Simulation of Electromagnetic Forming of Muffler Tube