The Effect of Tool–Sheet Interaction on Damage Evolution in Electromagnetic Forming of Aluminum Alloy Sheet

Imbert, J.; Winkler, S.; Worswick, Michael J.; Oliveira, D. A.; Golovashchenko, Sergey F.

doi:10.1115/1.1839212

Cited by 141 publications

(41 citation statements)

References 19 publications

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“…In the past few decades, many scholars pay much attention to the formability and microstructure evolution of various materials when using electromagnetic forming (EMF). For example, Imbert et al [1] demonstrated increased formability in AA5754 sheet formed into a conical die using EMF technology. Li et al [2] found that the forming limit of Ti-6Al-4V is increased by 24.37 % in electromagnetic free bulging.…”

Section: Introductionmentioning

confidence: 99%

Effect of the sheet thickness and current damping exponent on the optimum current frequency in electromagnetic forming

Cui

et al. 2015

Int J Adv Manuf Technol

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Current frequency is one of the key effect factors on forming efficiency during electromagnetic forming (EMF) process. In the past, many scholars considered that the optimum current frequency corresponds to the skin depth which should be less than workpiece thickness. This is because the magnetic field will greatly lose if the skin depth is larger than workpiece thickness. In this paper, the 2D sequence simulation method is utilized to predict the electromagnetic sheet bulging, and the simulation results are both in agreement with experimental results. It can be found that the larger of the magnetic field losses, the bigger displacement can be obtained in experiments. This is in stark contrast to previous results reported in literature. We also found that the sheet thickness and current damping exponent both have great effects on optimum current frequency if the discharging energy keeps constant, which can cause the skin depth corresponding to the optimum current frequency to be larger than the sheet thickness. Thus, the current frequency is a very complex factor on electromagnetic forming, and it is difficult to choose the optimum current frequency.

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Section: Introductionmentioning

confidence: 99%

Effect of the sheet thickness and current damping exponent on the optimum current frequency in electromagnetic forming

Cui

et al. 2015

Int J Adv Manuf Technol

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“…Hu and Daehn, 1996;Mercier and Molinari, 2004), and contact effects are known to strongly influence high velocity forming (e.g. Balanethiram and Daehn, 1994;Imbert et al, 2005). Finally, the present work makes the implicit assumption that the thermal response of the material is the same under quasistatic and EMF forming speeds.…”

Section: Resultsmentioning

confidence: 97%

Theory of necking localization in unconstrained electromagnetic expansion of thin sheets

Thomas

Triantafyllidis

2007

International Journal of Solids and Structures

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Certain sheet metal alloys of industrial interest show a significant increase in ductility, over conventional forming methods, when high speed electromagnetic processes are used. The present work models the necking localization of a metal sheet during an electromagnetic process and examines the factors that influence this process. A Marciniak-Kuczynski ''weak band'' model is used to predict the onset of necking of a thin sheet under plane stress, an idealization of the local conditions in a thin sheet subjected to unconstrained electromagnetic loading. It is found that electromagnetic forming (EMF) increases ductility over quasistatic techniques due to the material's strain-rate sensitivity, with ductility increasing monotonically with applied strain rates. The electric current also increases onset of necking strains, but the details depend on thermal sensitivity and temperature-dependence of the strain-rate sensitivity exponent. Given the insensitivity of the results to actual strain profiles, this local type analysis provides a useful tool that can be used for ductility predictions involving EMF processes.

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“…They found that substantially higher strains can be accomplished in the EHF process, comparison of the maximum strains NOMENCLATURE V = Forming velocity E = Discharge energy of system C = System capacitance U = Input voltage resulting from EHF into a conical die and a v-shape die with the maximum strains resulting from quasi-static LDH testing (limiting dome height). Imbert et al 7 illustrated increased formability in AA5754 sheet when formed into a conical die using electromagnetic forming technology. They utilized a damage-based material model to demonstrate that the tool-sheet interaction had a signicant effectin suppressing necking and damage evolution.…”

Section: Introductionmentioning

confidence: 98%

Experimental and numerical research on process formability in magnetic pulse forming of AZ31 magnesium alloy sheets

Cui

Sun

et al. 2015

Int. J. Precis. Eng. Manuf.

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The plain strain of AZ31 magnesium alloy sheet in magnetic pulse forming was investigated by numerical simulation and experimental method. Combination of uniform pressure coil and Holmberg's specimen was employed to evaluate the plain strain of AZ31 sheet. The numerical simulation for magnetic pulse plain strain of AZ31 sheet is performed by means of ANSYS FEA software. The magnetic flux density of uniform pressure coil was distributed uniformly, especially at the center of gauged area of AZ31 sheet directly in relation to the deformation behavior of AZ31 sheet. The velocity of typical point increases as increasing energy, and the more position closes to the center of sheet the higher velocity achieves. The forming height is increased with increasing discharge voltage. Compared with C=768 µF and C=1536 µF, the capacitance of 1152 µF is more effective for forming, which is confirmed by experiments. The peak velocity at the center of sheet is about 105 m/s. The major strains of magnetic pulse plane strain lie approximately in the strain ranges of 5.83-6.45%. However, the 3.22-3.82% (major strain) are the limit strains in quasi-static condition. The experimental results indicate that the major strain of AZ31 sheet improves about 75% compared with the quasi-static case.

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The Effect of Tool–Sheet Interaction on Damage Evolution in Electromagnetic Forming of Aluminum Alloy Sheet

Cited by 141 publications

References 19 publications

Effect of the sheet thickness and current damping exponent on the optimum current frequency in electromagnetic forming

Effect of the sheet thickness and current damping exponent on the optimum current frequency in electromagnetic forming

Theory of necking localization in unconstrained electromagnetic expansion of thin sheets

Experimental and numerical research on process formability in magnetic pulse forming of AZ31 magnesium alloy sheets

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