Verification of dynamic flow stress obtained using split Hopkinson pressure test bar with high-speed forming process

2016 ◽  
Vol 91 (1-4) ◽  
pp. 629-640 ◽  
Author(s):  
Hak-Gon Noh ◽  
Woo-Jin An ◽  
Hyeong-Gyu Park ◽  
Beom-Soo Kang ◽  
Jeong Kim
Keyword(s):  
Flow Stress ◽  
High Speed ◽  
Dynamic Flow ◽  
Forming Process ◽  
Pressure Test ◽  
High Speed Forming ◽  
Split Hopkinson

Joining of Tubular Parts by Electromagnetic Forming; Experimental Investigations

2014 ◽  
Vol 792 ◽  
pp. 115-120 ◽  
Author(s):  
Pál Rácz ◽  
Nándor Göbl ◽  
Daniel Horváth ◽  
Athanasios G. Mamalis
Keyword(s):  
High Speed ◽  
New Technologies ◽  
Dissimilar Materials ◽  
High Energy ◽  
Mechanical Tests ◽  
Electromagnetic Forming ◽  
High Energy Density ◽  
Experimental Investigations ◽  
Forming Process ◽  
High Speed Forming

Electromagnetic forming is a high speed forming process, wherein the forming pressure is created by high energy density electromagnetic pulse. Besides direct shaping there are other application areas as well, so electromagnetic plastic forming is a potential field of creating joints between tube and rod-like components. Connecting components of dissimilar materials is an increasing demand in the manufacturing process of structures in the automotive industry. The application of new technologies, such as electrodynamic, especially electromagnetic forming, is a possible method to satisfy these demands. The article summarizes the most important fundamentals of electromagnetic forming; in particular, tube-rod joints, the main types of such joints; interference-fit and form-fit joints are described. Experiments, which were carried out producing tube-rod joints with electromagnetic forming, are also introduced. A new type of form-fit joints for tube-rod connections has been developed, which can withstand not only tensile loads but also torsion. Experiments and mechanical tests have proved the applicability of this kind of joints.

scholarly journals An All-Atom Simulation Study of Gas Detonation Forming Technique

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 611
Author(s):  
Ambarish Kulkarni ◽  
Vispi Karkaria ◽  
Milankumar Nandgaonkar ◽  
Sandeep P. Patil ◽  
Bernd Markert
Keyword(s):  
High Speed ◽  
Md Simulations ◽  
Dome Height ◽  
Forming Process ◽  
Gas Detonation ◽  
Failure Patterns ◽  
Deformation Response ◽  
Applied Loading ◽  
Wide Range ◽  
High Speed Forming

The high-speed forming process is the key to attaining difficult and irregular profiles on ductile materials. In the present work, we proposed the all-atom model of the gas detonation forming process, wherein molecular dynamics (MD) simulations were performed on the aluminum workpiece at different loading speeds similar to the various pressure values in the process. The deformation response of an aluminum workpiece for a wide range of loading speeds, 0.1–8 Å/ps, was investigated. The dome-height, failure patterns, and formability of the aluminum workpiece were examined for these loading speeds. We obtained an inverse relationship between the formability of the aluminum workpiece and the applied loading speed. Moreover, in this work, the influence of the different percentage of defects in the workpieces on the mechanical behavior was investigated. We observed that at lower speeds (< 2 Å/ps), the deformation is observed throughout the workpiece starting from the point of contact in the middle and that is contrary to the deformations observed due to the higher loading speed where localized deformations occur due to creation of slipping planes. We also found that the internal voids lead to the rearrangement of atoms to facilitate the movement of slipping planes leading to better formability compared to the no-void workpieces. This work helps to get a fundamental understanding of deformation behavior in the high-speed forming process with and without defects in the aluminum workpiece at the nanoscale.

scholarly journals A Laboratory-Scale Instrumented Forging Hammer as an Intermediate Strain Rate Testing Device

2021 ◽  
Vol 250 ◽  
pp. 01002
Author(s):  
Julen Agirre ◽  
Borja Erice ◽  
David Abedul ◽  
Eneko Saenz de Argandoña ◽  
Nagore Otegi ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Split Hopkinson Pressure Bar ◽  
Material Model ◽  
Industrial Applications ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Mechanical Characterisation ◽  
High Speed Forming ◽  
Split Hopkinson

Mechanical characterisation of metallic materials at intermediate strain rates is essential to calibrate and validate computational models for industrial applications such as high-speed forming processes i.e. hammer forging, blanking, forming, etc. The most common devices that perform medium to high loading rate experiments are the servo-hydraulic universal testing machines and Split Hopkinson bar systems. Here we analyse the possibility of employing an in-house designed and constructed DirectImpact Drop Hammer (DIDH) for material mechanical characterisation at medium strain rates, ranging from 100 to 300 s-1. To show the suitability of the DIDH for mechanical characterisation, uniaxial compression experiments on S235JR structural steel are conducted and compared with finite element (FE) simulations performed with an elasticthermoviscoplastic material model previously calibrated with Split Hopkinson Pressure Bar (SHPB) tests.

Electromagnetic Sheet Bulging: Analysis of Process Parameters by FE Simulations

2013 ◽  
Vol 554-557 ◽  
pp. 741-748 ◽  
Author(s):  
Joao Pedro M. Correia ◽  
Saïd Ahzi
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
High Speed ◽  
Finite Element Simulations ◽  
Electromagnetic Forming ◽  
Forming Process ◽  
High Speed Forming ◽  
Bulging Test ◽  
High Repeatability

Electromagnetic forming is a non-conventional forming process and is classified as a high-speed forming process. It provides certain advantages as compared to conventional forming processes: improved formability, high repeatability and productivity, reduction in tooling cost and reduction of springback and of wrinkling. However, various process parameters affect the performance of the electromagnetic forming system. Finite element simulations are very useful to optimize a process because they can reduce time and costs. With the aim of investigating the effects of the process parameters on the deformed blank geometry, finite element simulations of an electromagnetic sheet bulging test have been performed in this work. Furthermore the role of first impulse of discharged current is also investigated.

Study of Electromagnetic Forming Process on Tubular Components

2014 ◽  
Vol 592-594 ◽  
pp. 894-898
Author(s):  
K. Sriram ◽  
Karibeeran Shanmuga Sundaram ◽  
P. Arumugam
Keyword(s):  
High Speed ◽  
Electromagnetic Forming ◽  
Work Piece ◽  
Forming Process ◽  
Compression Process ◽  
Aluminium Copper ◽  
High Speed Forming ◽  
Set Up ◽  
Tubular Components ◽  
Forming Methods

Forming processes are defined as to modify the shape of a work piece by deforming it, without the removal of material. To overcome a number of longstanding problems in conventional forming methods such as low production rates, difficulty in forming light weight components etc., an alternate approach of electromagnetic forming process is introduced. Electromagnetic forming (EMF) is a high speed forming process used to form thinwalled work pieces (usually sheets and tubes) that have high electrical conductivity, such as aluminium, copper etc. Electromagnetic tube compression processes, the design of an experimental set up for electromagnetic tube compression process are discussed in detail in this paper

Electromagnetic Embossing of Optical Microstructures

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Lasse Langstädtler ◽  
Lars Schönemann ◽  
Christian Schenck ◽  
Bernd Kuhfuss
Keyword(s):  
Cross Section ◽  
High Speed ◽  
Machining Process ◽  
Average Surface Roughness ◽  
Forming Process ◽  
High Deformation Rate ◽  
Average Surface ◽  
High Deformation ◽  
Cube Corner ◽  
High Speed Forming

Electromagnetic forming (EMF) is a high-speed forming process that is already established in the macroworld. Due to its advantages like high deformation rate and cheaper tools, it is introduced to microforming. In this research, the replication of prismatic optical microstructures is investigated. EN AW-1050A (Al99.5) micrometal sheets with a thickness of 50 μm and 300 μm are electromagnetically micro-embossed. With this technique, it is possible to successfully replicate triangular cross section micro V-grooves of 86.6 μm in width and 24.1 μm in depth with an average surface roughness of Sa = 44 nm. The microstructures of the embossing tool are generated by diamond micro chiseling (DMC), a novel machining process to produce microstructures with discontinuous geometry, like miniature cube corner retro reflectors and V-grooves with well-defined endings.

scholarly journals RESEARCH ON MATERIAL FLOW-STRESS BEHAVIOR AND THE DIE-FORGING PROCESS FOR FORGED-STEEL BRAKE DISCS FOR HIGH-SPEED TRAINS

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Zhenhong Li ◽  
Chenxing Zhang ◽  
Chenyu Wang ◽  
Yingna Huang
Keyword(s):  
Flow Stress ◽  
Process Parameters ◽  
High Speed ◽  
Brake Disc ◽  
Test Machine ◽  
Forming Process ◽  
Finite Element Software ◽  
Die Forging ◽  
Brake Discs ◽  
High Speed Trains

Due to the large size and complicated features, the brake discs of high-speed trains are difficult to forge, so a reasonable design of the process and the die parameter are prerequisites for successful forming. The flow stress of 23CrNiMoV, a forged-steel brake disc material for high-speed trains, was investigated by a uniaxial compression experiment on a Gleeble 1500 test machine. Based on the obtained flow-stress data, a series of numerical simulation analyses of the die forging of high-speed-train brake discs were carried out by using finite-element software. The effects of forging temperature, flash groove parameters and forming speed on the flow filling, forming load and temperature change of metal during die forging were studied. The simulation results were optimized and better process parameters were obtained. Based on the obtained process parameters, the simulation of the forming process was completed and a better forming quality was obtained.

scholarly journals Numerical Study of Electrohydraulic Forming to Reduce the Bouncing in High Speed Forming Process

2016 ◽  
Vol 25 (4) ◽  
pp. 261-267 ◽  
Author(s):  
M.A. Woo ◽  
H.G. Noh ◽  
W.J. Song ◽  
B.S. Kang ◽  
J. Kim
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
High Speed Forming

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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