Sheet metal electromagnetic forming using a flat spiral coil: Experiments, modeling, and validation

Paese, Evandro; Geier, Martin; Homrich, Roberto Petry; Rosa, P.A.R.; Rossi, Rodrigo

doi:10.1016/j.jmatprotec.2018.08.033

Cited by 37 publications

(10 citation statements)

References 15 publications

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“…The equivalent circuit equations are used to calculate the discharge current, which can be written as [30, 35].

(R_{1} I_{L} + L_{1} \frac{normald I_{L}}{normald t}) + V_{c o i l} = U_{normalc}

U_{normalc} + \frac{1}{C} \int_{0}^{t} I_{L} normald t = U_{0}

V_{c o i l} = R_{c} I_{L} + L_{c} \frac{d I_{L}}{d t} + M_{c - w} \frac{d I_{normalw}}{d t}

where

R_{1}

is the line resistance,

I_{L}

is the discharge current,

L_{1}

is the line inductance,

V_{c o i l}

is the voltage of the coil,

U_{c}

is the voltage of the capacitor bank,

C

is the capacitance of the capacitor bank,

U_{0}

is the initial voltage of the capacitor bank,

R_{c}

is the coil resistance,

L_{c}

is the self‐inductance of the coil,

M_{c - w}

is the mutual inductance between the coil and the workpiece,

I_{w}

is the eddy current in the workpiece.…”

Section: Numerical Model and Experimental Setupmentioning

confidence: 99%

The importance of coil conductivity and eddy current effects in the analysis of electromagnetic forming process

et al. 2021

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Coil design and performance analysis are critical for the electromagnetic forming (EMF) process. However, previous studies have paid little attention to the coil conductivity, and the influence of eddy current effects in coil conductors on the forming process has not been well understood. This work aims to address these problems through numerical and experimental investigations. It is found that, due to the eddy current effects, the uneven current distribution appears in the coil conductors that should be considered when analysing the forming process, especially for the cases with large heights of coil conductors. Meanwhile, an important and interesting discovery is that the eddy current effects can greatly reduce the sensitivity of the coil conductivity with respect to the workpiece deformation, the Joule heating and the temperature rise in the coil. For instance, compared to a forming system with a copper coil, the forming height of the workpiece in the forming system with an AA5083-O coil is reduced by less than 5 % under the same discharge energy, while the copper conductivity is 3.3 times that of the latter. These results are helpful to understand the EMF process and achieve the optimal design of coils.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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“…The equivalent circuit equations are used to calculate the discharge current, which can be written as [30, 35].

(R_{1} I_{L} + L_{1} \frac{normald I_{L}}{normald t}) + V_{c o i l} = U_{normalc}

U_{normalc} + \frac{1}{C} \int_{0}^{t} I_{L} normald t = U_{0}

V_{c o i l} = R_{c} I_{L} + L_{c} \frac{d I_{L}}{d t} + M_{c - w} \frac{d I_{normalw}}{d t}

where

R_{1}

is the line resistance,

I_{L}

is the discharge current,

L_{1}

is the line inductance,

V_{c o i l}

is the voltage of the coil,

U_{c}

is the voltage of the capacitor bank,

C

is the capacitance of the capacitor bank,

U_{0}

is the initial voltage of the capacitor bank,

R_{c}

is the coil resistance,

L_{c}

is the self‐inductance of the coil,

M_{c - w}

is the mutual inductance between the coil and the workpiece,

I_{w}

is the eddy current in the workpiece.…”

Section: Numerical Model and Experimental Setupmentioning

confidence: 99%

The importance of coil conductivity and eddy current effects in the analysis of electromagnetic forming process

et al. 2021

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“…The generated electromagnetic (EM) force speeds-up the plate to accomplish the required formation [27]. Traditional flat coils will simultaneously produce axial and radial magnetic flux in the vicinity of the plate [7]. The bulging of the plate is mainly due to the axial electromagnetic force generated by the interaction of the radial magnetic flux density and the induced eddy current on the plate.…”

Section: Emf Principle and The Proposed Topologymentioning

confidence: 99%

“…The conventional quasi-static stamping process results in poor formability of the aluminum alloy sheet, especially when the drawing ratio increases [4,5]. Electromagnetic forming (EMF) is based on using pulsed electromagnetic-force to realize the processing of a metal plate [6][7][8]. Compared with conventional mechanical processing, electromagnetic forming can improve materials deformation performance and enhance its forming margin by 5-10 times due to its high strain rate (10 3 -10 5 s -1 ) [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Study of a Topology for Plate Electromagnetic Forming Based on Inner Reverse and Outer Positive Double Coil Loading

et al. 2020

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While electromagnetic forming is widely used for aluminum alloy materials, the nonuniformity of plate radial deformation is still a key issue that restricts the wide development of this technology. This paper presents a new electromagnetic-forming topology. The proposed topology comprises outer ring double-coil plates along with an inner loop driving coil of a small number of turns whose geometrical parameters are optimized to adjust the induced eddy current of the plate. Numerical simulation results show that the presence of an inner ring driving coil shapes the magnetic field in a manner that the radial electromagnetic force is concentrated close to the edge of the die which affects the center of the plate. With optimum design for the geometrical parameters of the proposed inner ring driving coil, the electromagnetic force distribution can be adjusted over the plate, resulting in an improved plate deformation with an increase in the maximum uniform deformation area from 24mm to 65mm. Results also show that the proposed inner and outer ring double coil loading method possesses superior advantages over the traditional flat spiral coil loading method.

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“…Nevertheless, due to the non-axisymmetric structure of the helical coil, it is very difficult to establish the actual helical coil model, which eventually leads to a sharp increase in the high precision calculation of the magnetic field, and the simulation results cannot converge. Hence, researchers usually use software such as COMSOL [12][13][14] , ANSYS/MEGA [15][16] and LS-DYNA [17][18] to analyze the magnetic field by equating the solenoid coil model with a 2-D or 3-D axisymmetric model. What's more, these studies mainly focus on aspects such as electromagnetic bulging [19][20] , electromagnetic welding [21][22] , electromagnetic superposed forming [23] , and the electromagnetic-assisted forming [24][25] .…”

Section: Introductionmentioning

confidence: 99%

Pitch Effect of Helical Coils of Electromagnetic Forming

Zhang

Zhou

Liang³

et al. 2020

IEEE Access

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Sheet metal electromagnetic forming using a flat spiral coil: Experiments, modeling, and validation

Cited by 37 publications

References 15 publications

The importance of coil conductivity and eddy current effects in the analysis of electromagnetic forming process

The importance of coil conductivity and eddy current effects in the analysis of electromagnetic forming process

Study of a Topology for Plate Electromagnetic Forming Based on Inner Reverse and Outer Positive Double Coil Loading

Pitch Effect of Helical Coils of Electromagnetic Forming

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