Mechanical crimping is the most used method of pressure connection for permanent electrical contact in electrical and electronic equipment. Terminal plastic deformation on multi-wire strands is ...carried out to achieve mechanical strength and electrical conductivity. Electromagnetic (EM) is assumed to be an alternative method to overcome the challenges of spring back in the terminal on tool relaxation, cracks, non-uniform deformation, reduced strength, decreased the durability of joints in conventional crimping tool. Implementation of the field shaper (FS) has been proposed to enhance the magnetic field to concentrate the magnetic pressure at the required location for the effective terminal crimping over the wire strands. In this work, crimping was carried out using FS as a tool. Experiments were carried out utilizing tapered FS, single step FS and double step FS on aluminum terminal over seven strands aluminum wire strands that are commercially utilized for making interconnections. Results like contact length, contact resistance, terminal deformation, surface hardness, cross-section hardness and pull-out tests were found out and compared simultaneously. Also, the test results were compared with the samples crimped using a conventional crimping tool. From the results single step FS was found to be the most efficient FS than double step FS whereas the tapered FS was the least efficient. The results will be helpful in determining the geometry for the field shapers in similar applications.
In this study, two sheets of AA5052 are joined with the high-strain-rate multi-spot joining process using an electromagnetic system. While producing a single spot joint by electromagnetic joining ...(EMJ) is common, the distribution and application of the pressure can be modified by the design of the coil and spacers to make multiple joints at once. When a preformed dimple is used to provide the standoff distance, it can eliminate the need for spacers and provide good aesthetics for the final product. In the current study, a joint design is developed to provide three spot joints coincidentally by a single discharge of a capacitor bank. For the experiment, four distinctive discharge energies were used for joining: 7, 8, 9, and 10 kJ. The most successful joint sample was made by 8 kJ and was tested for mechanical properties. The cross-section was observed in order for us to understand the joint quality produced by the process. It was found that the ”I”-shaped rectangular coil produces a variable magnetic flux, leading to different flyer deformation variations in the joint geometry. At the centre of the ”I” coil, the minimum flux was predicted, leading to lesser sheet forming, hence a weaker centre-spot joint strength. Further, a numerical study is performed to find the Von Mises stresses, equivalent plastic strain, impact velocity, and impact pressure on the sheets. This manuscript provides new information regarding coil designing and the changes that could be further made to improve the electromagnetic sheet multi-spot joining process.
Electromagnetic terminal-wire crimping (EMTWC) is a type of mechanical joining process. In EMTWC, the terminal is deformed over the wire strands plastically to enhance the mechanical strength by ...increasing the contact area. A well-crimped electrical interconnection helps to avoid harmful configurations by reducing sparks, overheating, power losses etc. Subsequently, the challenge to minimize various disadvantages of conventional mechanical terminal-wire crimping process like non-uniform deformation, decreased durability, cracks, etc., can be overcome by the electromagnetic crimping process. In this work, application of the fieldshaper has been proposed to concentrate the magnetic pressure at the desired location for effective wire crimping. Numerical analysis was carried out using LS-DYNA
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on three different types of field-shaper namely single-step, double-step and tapered. In all the three field-shaper, the total length, the outer diameter and the effective working length were constant. The samples used was an aluminum terminal and seven strands of aluminum wires which are commercially used for making electrical inter connections. Experiments were carried out based on the results obtained through numerical analysis. Experimental and numerical results were in agreement and the error was less than 10%. The efficiency of single-step field-shaper was found to be better compared to double-step and tapered fieldshaper.
Electromagnetic forming is a high strain rate and high-speed forming process. This manuscript uses an electromagnetic forming technique to predict the failure zone in forming AA 6061. Concerning the ...die, entry radius is made using the experimental and simulation approach. Simulations performed to free-formed dome height test of AA 6061 of 1 mm thickness with dimension 200 mm × 200 mm in commercially available computational Finite Element Method (FEM) software. The FEM software utilized for the purpose is the LS-Dyna EM module specially designed for EMF application and uses a robust coupling method. In the experimental result, shear failure of the blank occurs at the dome's base, similar to the simulation result. The failure occurs due to the extreme shear stress generated between the blank and die cavity opening. Intense pressure and the relatively sharp edge of the die entry radius contribute to excessive shear stress in the region. An increase in the discharge energy causes the shearing of the blank at the bottom of the dome.
Design of a field shaper plays an essential role in the electromagnetic crimping process. It needs to be designed in such a manner that maximum magnetic field is concentrated at the active working ...zone. Simultaneously it is essential to take care of the mechanical strength of the field shaper so that the von Mises stress acting over the field shaper should always be lower than the strength of the material used for making field shaper. In this manuscript, numerical and experimental work is carried out in the variation of the effective height of the field shaper, to get the most suitable effective working zone height for maximum magnetic pressure acting over the workpiece. Research is carried out over the electrical interconnectors as an application, to achieve maximum crimping of the terminal over the wire strands. Results like the current density Von-Mises stress, magnetic field, Lorentz force, terminal deformation, and contact length are discussed in detail. These results will help to design a field shaper for different industrial applications.
Electromagnetic crimping of cylindrical components is an environmentally friendly, solid-state material joining process where a flyer metal tube makes a high-speed collision with a target material. ...Aluminum and Carbon Fiber Reinforced Polymer (CFRP) are lightweight and possess a high strength-to-weight ratio along with strong mechanical properties. Joining these materials quickly and securely is crucial when producing lightweight constructions such as aviation components, automotive parts, and recreational products. Electromagnetic crimping of CFRP and aluminum tubes have been investigated due to the increased use of these dissimilar material joints. This study uses a novel combination of spiral coil and step-taper field shaper to induce the magnetic field. AA 1050 and CFRP tubes are crimped at different energies of 4.73, 5.50, and 6.34 kJ. All the joints are compared concerning different parameters such as the pull-out test, compression shear test, torsion test, cross-section analysis, characterization, microhardness, and leakproof test. This manuscript discusses the effect of different discharge energies along with coil and field shaper design improvements for the electromagnetic crimping process.
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•Electromagnetic crimping numerical simulations are carried out.•Experiments are carried out using the numerical simulations results.•Experiments are carried out on the plain and ...threaded terminal for comparison.•Results of terminal deformation, cross-section analysis, contact resistance, pull-out test and hardness along the cross-section are discussed.•Electromagnetic crimping can be an alternative to conventional wire crimping process with many advantages.
Crimping of terminals to wire strands is crucial in electrical power transmission system. It has been reported that, in electrical inter connections, 60% failure takes place in crimped junctions. Improving crimped connections can decrease the resistance to the current flow through terminals, reduced power loss, sparks, and over-heating in the joints etc. To overcome these problems occurring in conventional crimping process a novel technique for effective wire crimping has been proposed in this paper. A strong pulsed electromagnetic field was used in wire crimping of aluminum terminal with copper wire. Numerical simulations were carried out using LS-DYNA™ software in the electromagnetic module. Its results were utilized to design the coil and to find the optimum discharge voltage required for uniform deformation of terminals. Experiments were carried out at optimized discharge voltages obtained from the numerical simulation results to demonstrate the feasibility of electromagnetic wire crimping process. Effect of the threaded and plain profile of crimped terminals was investigated. Results like terminal deformation, cross-sectional analysis, contact resistance, pullout strength and hardness testing were carried out. This work will be helpful to the industries where wire crimped connections are used in large numbers.
•Electromagnetic wire crimping process is investigated.•Experimental work is carried out to show the advantages of electromagnetic wire crimping process over conventional crimping process.•A new ...electromagnetic wire crimping process is developed.
Crimping of lugs to wire strands is a crucial part in electrical power transmission process. Improper design increases the resistance of current flow through terminals and causes problems like power loss, spark and heating in the joint. Which affect many industries like shipping, automobile, aerospace, satellite and communication where cable connections are used in large quantities. Electricity distribution boards faces similar problems during generation due to improper connection. To overcome these problems in conventional crimping process a new novel technique for effective wire crimping has been proposed in this paper. A strong pulsed electromagnetic (EM) field is used in wire crimping of aluminium connector terminal with copper wire. Experiments are carried out at different discharge voltages to demonstrates the feasibility of EM wire crimping process and to study the properties. With developed method, positive results were found from EM crimped samples. The gap between aluminium connector terminal and copper wire was reduced by 70% than conventional process. The electrical resistance of EM process was decreased by 34% than conventional one. Its pullout strength is 978N higher. The surface finish is improved as mean roughness value of 0.8μm. The hardness was reached up to 47 HV0.1. X- ray diffraction (XRD) technique was used to find the residual stresses in EM and conventional crimped samples. Thermal behavior is improved over conventional crimped process.
Electromagnetic (EM) terminal - wire crimping process, is a non-conventional high-speed crimping process using the energy density of a pulsed EM field. A subsequent coupled field analysis of EM ...terminal - wire crimping was performed using finite element method in LS-Dyna™. Simulations were carried out on aluminum terminal over aluminum wire strands using three different types of coil cross-section (trapezoidal, rectangular and circular geometry) with five turns helical coil. For the comparison cross-section (CS) area, and coil length was kept constant. The results obtained from the comparison were utilized for the fabrication of the coil. Validation of results was carried out using radial deformation and contact length between wire strands and terminal. The simulation predictions agree well with the experimental results. Some other important test results like electrical contact resistance, hardness, and pullout test were also carried out. Results show that the trapezoidal CS was the optimum geometry among the rectangular CS and the circular CS, which also shows that change in geometry, can enhance the crimping process in many parameters, which are discussed in this paper. The new outcomes of research would be helpful in determining the optimum geometry for the helical coils in similar applications.
•FST has been successfully applied to six binary ionic liquid mixtures.•Only ρ and u have been used to compute a number of useful and important thermodynamic and thermoacoustical properties.•The ...validity of FST for pure ionic liquids and their binary mixtures has been tested from the theoretical values of σ and u.•The magnitudes of u, Pint, E and ΔHv, ced, δ and n obtained from FST demonstrate the excellent agreements.
For the first time, widely employed Flory’s statistical theory of binary liquid mixtures has been successfully applied to six binary ionic liquid mixtures. Only density and sound speed data have been used to compute a number of useful and important thermodynamic and thermoacoustical properties of DEAA + H2O, DEAS + H2O, TEAA + H2O, TEAS + H2O, TMAA + H2O and TMAS + H2O at 298.15 K. Experimental values of density and sound speed were taken from the recent work of Venkatesu et al J P C 118B (2014) 5971.
Their data are rare, very precise and accurate. The validity of FST for pure ionic liquids (RTIL’s) and their binary mixtures has been tested from the theoretical values of surface tension and sound speed. The magnitudes of sound speed, internal pressure, energy and heat of vaporization, cohesive energy density, solubility parameter and polarity factor obtained from FST demonstrate the excellent agreement with the available values of the experimental properties.
