Enhancement of Formability of AA5052 Alloy Sheets by Electrohydraulic Forming Process

2016 ◽  
Vol 26 (1) ◽  
pp. 439-452 ◽  
Author(s):  
Meraj Ahmed ◽  
D. Ravi Kumar ◽  
M. Nabi
Keyword(s):  
Forming Process ◽  
Electrohydraulic Forming

scholarly journals Acquisition and Evaluation of Theoretical Forming Limit Diagram of Al 6061-T6 in Electrohydraulic Forming Process

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 401 ◽  
Author(s):  
Min-A Woo ◽  
Woo-Jin Song ◽  
Beom-Soo Kang ◽  
Jeong Kim
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
Al 6061 ◽  
Shpb Test ◽  
Strain Rate Hardening ◽  
Free Bulging

The current study examines the forming limit diagram (FLD) of Al 6061-T6 during the electrohydraulic forming process based on the Marciniak–Kuczynski theory (M-K theory). To describe the work-hardening properties of the material, Hollomon’s equation—that includes strain and strain rate hardening parameters—was used. A quasi-static tensile test was performed to obtain the strain-hardening factor and the split-Hopkinson pressure bar (SHPB) test was carried out to acquire the strain rate hardening parameter. To evaluate the reliability of the stress–strain curves obtained from the SHPB test, a numerical model was performed using the LS–DYNA program. Hosford’s yield function was also employed to predict the theoretical FLD. The obtained FLD showed that the material could have improved formability at a high strain rate index condition compared with the quasi-static condition, which means that the high-speed forming process can enhance the formability of sheet metals. Finally, the FLD was compared with the experimental results from electrohydraulic forming (EHF) free-bulging test, which showed that the theoretical FLD was in good agreement with the actual forming limit in the EHF process.

scholarly journals Development of Electrohydraulic Forming Process for Aluminum Sheet with Sharp Edge

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ji-Yeon Shim ◽  
Bong-Yong Kang
Keyword(s):  
High Velocity ◽  
Forming Limit Diagram ◽  
Sharp Edge ◽  
Dome Height ◽  
Forming Limit ◽  
Radius Of Curvature ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
Forming Technology ◽  
Sharp Edges

Electrohydraulic forming (EHF), high-velocity forming technology, can improve the formability of a workpiece. Accordingly, this process can help engineers create products with sharper edges, allowing a product’s radius of curvature to be less than 2 mm radius of curvature. As a forming process with a high-strain rate, the EHF process produces a shockwave and pressure during the discharge of an electrical spark between electrodes, leading to high-velocity impact between the workpiece and die. Therefore, the objective of this research is to develop an EHF process for forming a lightweight materials case with sharp edges. In order to do so, we employed A5052-H32, which has been widely used in the electric appliance industry. After drawing an A5052-H32 Forming Limit Diagram (FLD) via a standard limiting dome height (LDH) test, improvements to the formability via the EHF process were evaluated by comparing the strain between the LDH test and the EHF process. From results of the combined formability, it is confirmed that the formability was improved nearly twofold, and a sharp edge with less than 2 mm radius of curvature was created using the EHF process.

Optimization of electrohydraulic forming process parameters using the response surface methodology

2021 ◽  
Vol 63 (6) ◽  
pp. 571-580
Author(s):  
Balasubramanian Arun Prasath ◽  
Pasupathy Ganesh ◽  
Karibeeran Shanmuga Sundaram
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Process Parameters ◽  
Standoff Distance ◽  
Optimum Process ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
Acceptable Range ◽  
Steel Aisi ◽  
Experimental Values

Abstract This work’s main objective is to determine the optimum process parameters in the electrohydraulic forming (EHF) of austenitic stainless steel AISI 304 of 0.25 mm thickness for macro and micro shape. A truncated cone with grooves in the apex is considered as macro-micro shape. The response surface methodology (RSM) was developed for process variables such as voltage and standoff distance to determine the optimum parameters. To validate the model, confirmation experiments have been conducted, i. e. for the optimum value of voltage (V) = 8.935 kV and standoff distance (SOD) = 40.60 mm, and from the experiments the forming depth predicted is 9.221 mm and depth from the experiments is 9.5 mm. The percentage deviation from the predicted and experimental forming depth is 3.025 %, an acceptable range of less than 5 % for the surface roughness, the predicted value is 0.2598 microns, and the experimentally measured value is 0.268. The percentage deviation is 3.156 % between the predicted and experimental values, an acceptable range of less than 5 %. This shows that the model is suitable for predicting both responses. The validation experiments also found that the sheet fills one of the grooves and partially fills the other, which shows the capability of the electrohydraulic forming process. Confirmation experiments have been conducted.

Determination of High Strain-Rate Behavior of Metals: Applications to Magnetic Pulse Forming and Electrohydraulic Forming

2014 ◽  
Vol 611-612 ◽  
pp. 643-649 ◽  
Author(s):  
Anne Claire Jeanson ◽  
Gilles Avrillaud ◽  
Gilles Mazars ◽  
Jean Paul Cuq-Lelandais ◽  
Francois Bay ◽  
...  
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Expansion Velocity ◽  
Magnetic Pulse ◽  
Constitutive Behaviour ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
Workpiece Material ◽  
Magnetic Pulse Forming ◽  
Static Conditions

The design of processes like magnetic pulse forming and electrohydraulic forming involves multiphysical couplings that require numerical simulation, and knowledge on dynamic behaviour of metals. The forming process is completed in about 100 μs, so that the workpiece material deforms at strain-rates between 100 and 10 000 s-1. In this range, the mechanical behaviour can be significantly different than that in quasi-static conditions. It is often noticed that the strength and the formability are higher. The main goal of this study is to use an electromagnetically driven test on tubes or sheets to identify the constitutive behaviour of the workpiece material. In the case of tube, an industrial helix coil is used as inductor. Simulations with the code LS-Dyna® permit to find a configuration where the tube deforms homogeneously enough to allow axisymmetric modelling of the setup. The coil current is measured and used as an input for the simulations. The radial expansion velocity is measured with a Photon Doppler Velocimeter. The parameter identification is lead with the optimization software LS-Opt®. LS-Dyna axisymmetric simulations are launched which different set of parameters for the constitutive behaviour, until the computed expansion velocity fits the experimental velocity. The optimization algorithm couples a gradient method and a global method to avoid local minima. Numerical studies show that for the Johnson-Cook constitutive model, two or three experiments at different energies are required to identify the expected parameters. The method is applied to Al1050 tubes, as received and annealed. The parameters for the Johnson-Cook and Zerilli-Armstrong models are identified. The dynamic constitutive behaviour is compared to that measured on quasi-static tensile tests, and exhibits a strong sensitivity to strain-rate. The final strains are also significantly higher at high velocity, which is one of the major advantages of this kind of processes.

Aspects of Electrodynamic Forming Processes

2013 ◽  
Vol 767 ◽  
pp. 126-131
Author(s):  
Pál Rácz ◽  
Nándor Göbl ◽  
Daniel Horváth ◽  
Athanasios G. Mamalis
Keyword(s):  
Capacitor Bank ◽  
High Energy ◽  
Discharge Process ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
Energy Rate ◽  
High Energy Rate ◽  
Released Energy ◽  
Assembly Operations ◽  
Short Time

Two types of electrodynamic forming process have been developed: electromagnetic and electrohydraulic forming. In the case of electromagnetic forming, the energy stored in a capacitor bank is discharged through a coil, which means that the electrical interaction between the coil and the plate or a tubular part to be formed results in deformation of the workpiece. However, in the case of electrohydraulic forming, the capacitor bank is discharged through a spark gap or filament wire; the deformation of the workpiece is due to the shockwaves, generated by the discharge process in a transmitting medium. In both processes, a large amount of energy is released in extremely short time, therefore these processes are considered to be high energy rate forming processes. These high energy rates, result in increasing the formability of the materials in many cases, and obtain significant deformations also for some materials that normally do not behave plastically. The utilization of the energy stored in the capacitor bank is significantly better in the case of electrohydraulic forming, because the released energy is converted directly to pressure waves, results in forming of higher strength materials. Both metallic and non-metallic materials can be formed by the technologies of electromagnetic and electrohydraulic technologies. In the present paper some aspects and applications of these high energy rate methods are briefly outlined mainly focusing on the automotive industry, involving expansion or compression forming of tubular parts, joining and assembly operations.

Experimental and Numerical Analyses of Tubular Electrohydraulic Forming Process

2021 ◽  
Vol 871 ◽  
pp. 80-86
Author(s):  
Ya Nan Wei ◽  
Fei Fei Zhang ◽  
Bo Wei ◽  
Hui Xu ◽  
Kai He
Keyword(s):  
High Speed ◽  
Discharge Voltage ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
High Speed Forming ◽  
Forming Efficiency ◽  
History Of ◽  
Instantaneous Discharge ◽  
And Performance ◽  
Forming Methods

Electrohydraulic forming (EHF) is a kind of high speed forming process, which deforms the metal by shock wave through instantaneous discharge of high voltage in water. Compared with the traditional forming methods, this high speed forming process can greatly improve the formability of the materials. There are many processing factors that affect the forming efficiency and performance of the electrohydraulic forming process, one of which is the discharge voltage between the electrodes. In this paper, three electrohydraulic forming experiments with various die shapes were carried out under various discharge voltage conditions. And the bulge height and axial length of the aluminum alloy A6061 tubes under different conditions were compared. Besides, finite element numerical simulation was also performed to quantitatively investigate the deformation history of the tube.

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