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.

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.

Magnetic Pulse Forming of Thin-Aluminum Sheet Using Bar-Forming Coil

2011 ◽  
Vol 337 ◽  
pp. 621-624 ◽  
Author(s):  
Ji Yeon Shim ◽  
Ill Soo Kim ◽  
Dong Hwan Park ◽  
Bong Yong Kang
Keyword(s):  
Intelligent System ◽  
Analysis Data ◽  
Aluminum Sheet ◽  
Design Parameters ◽  
Fe Model ◽  
Magnetic Pulse ◽  
Forming Process ◽  
Thin Aluminum ◽  
Magnetic Pulse Forming ◽  
Measured Strain

Generally a MPF(Magnetic pulse forming) process refers to the high velocity and high strain rate deformation of a low-ductility materials driven by electromagnetic forces that are generated by the rapid discharge current through the forming coil. The goal of this study was to investigate the main design parameter in MPF. To achieve the above objectives, An intelligent system which consisted of thin 5053 aluminum sheet and bar forming coil was employed for the experiment. The measured strain data have been analyzed using the developed electromagnetic FE-model. The analysis data showed that the uniform electromagnetic force is one of most important design parameters in MPF process.

scholarly journals Modeling of thin sheet forming processes by combining solid-shell finite element with isotropic elastoviscoplastic model. Application to magnetic pulse forming processes

2021 ◽  
Author(s):  
Mohamed Mahmoud ◽  
François Bay ◽  
Daniel Pino Mũnoz
Keyword(s):  
Sheet Metal ◽  
Thin Sheet ◽  
Magnetic Pulse ◽  
Solid Shell ◽  
Forming Process ◽  
Thin Structures ◽  
Shell Elements ◽  
Tetrahedral Element ◽  
Magnetic Pulse Forming ◽  
Assumed Strain

Sheet metal alloys are used in many industries to save material, reduce weight and improve the overall performance of products. For the last decades, many types of elements have been developed to resolve the locking problems encountered in the simulation of thin structures. Among these approaches, a family of assumed-strain solid-shell elements has proved to be very efficient and attractive in simulating thin 3D structures with various constitutive models. Furthermore, these elements are able to account for anisotropic behavior of thin structures since isotropic yield functions cannot capture the real physics of some forming processes. In this work, von Mises isotropic yield criterion with Johnson-cook hardening model are combined with a linear prismatic solid-shell element to simulate sheet metal forming processes. A new element assembly technique has been developed to permit the assembly of prismatic elements in a tetrahedral element-based software. This technique splits the prism into multiple tetrahedral elements in such a way that all the cross-terms are accounted for. Furthermore, a tetrahedral based partitioning code has been modified to account for the new prismatic element shape without changing the core structure of the code. More accurate results were obtained using low number of solid-shell elements compared to its counterpart tetrahedral element (MINI element). This reduction in the number of elements accelerated the simulation, especially in the coupled magnetic-structure simulation used for magnetic pulse forming process. The proposed element and criteria are implemented into FORGE (in-house code developed at CEMEF) for simulating magnetic pulse forming process.

Development of FE-Model for Al 5053 Sheet Plate Forming Using Electromagnetic Force

2011 ◽  
Vol 335-336 ◽  
pp. 1099-1102 ◽  
Author(s):  
Ji Yeon Shim ◽  
Ill Soo Kim ◽  
Ji Hye Lee ◽  
In Ju Kim ◽  
Bong Yong Kang
Keyword(s):  
Research Area ◽  
Fe Model ◽  
Magnetic Pulse ◽  
Plastic Working ◽  
Forming Process ◽  
3 Dimensional ◽  
Control Information ◽  
Magnetic Pulse Forming ◽  
Deformation Mechanics ◽  
Insight Into

Magnetic pulse forming is based on the principle of generation of a repulsive force called, Lorentz force due to opposing magnetic fields of adjacent conductors. Magnetic pulse forming of light weight materials such as aluminum, magnesium has been studied by many universities, institutes due to its advantages. But magnetic pulse forming is a complicated research area involving different topics in electromagnetic mechanics, plastic working, and materials mechanics. Therefore, development of FE-model of magnetic pulse forming process is a useful approach for better insight into workpiece deformation mechanics with electromagnetic interaction and further provides design and quality control information. To successfully accomplish this objective, a 3-dimensional ax-symmetric electromagnetic numerical model has been developed. The equation was solved using a general mechanics computer program, ANSYS EMAG and LS-DYNA code.

The Abnormal Deformation Behavior of B340/590 DP Steel at Elevated Temperature

2013 ◽  
Vol 275-277 ◽  
pp. 1843-1847
Author(s):  
Yu Qin Guo ◽  
Juan Juan Han ◽  
Meng Zhao ◽  
Wei Chen ◽  
Long Chen
Keyword(s):  
Strain Rate ◽  
Tensile Tests ◽  
Warm Forming ◽  
Effect Of Temperature ◽  
Process Conditions ◽  
Forming Process ◽  
Dp Steel ◽  
Deformation Behaviors ◽  
Temperature Ranges ◽  
Hardening Coefficient

A series of warm tensile tests for B349/590DP steel are performed at the stain rates of 0.0004/s, 0.001/s, 0.01/s and 0.08/s in this paper. From the test data, it is found that the effect of temperature and strain rate on material’s deformation behaviors is opposite to that of other temperature ranges. And with the change of strain rate and temperature, the relations between the material parameters such as the work-hardening exponent n, the stress hardening coefficient K and forming process conditions becomes uncertain. Moreover, authors investigated the reasons for above phenomena. Research results demonstrate that it is very necessary to appropriately optimize the warm forming process scheme and strictly control the warm forming process parameters so that both the formability and safety performance are considered simultaneously.

Constitutive Relationship of 3A21 Aluminium Alloy Tube for Magnetic Pulse Forming

2012 ◽  
Vol 239-240 ◽  
pp. 314-319
Author(s):  
Zhi Dan Xu ◽  
Jun Jia Cui ◽  
Hai Ping Yu ◽  
Chun Feng Li
Keyword(s):  
Constitutive Equation ◽  
Aluminium Alloy ◽  
Split Hopkinson Pressure Bar ◽  
Constitutive Relationship ◽  
Dynamic State ◽  
Magnetic Pulse ◽  
Forming Process ◽  
Alloy Tube ◽  
Magnetic Pulse Forming ◽  
Aluminum Alloy Tube

In this work, Split Hopkinson Pressure Bar (SHPB) was employed to test the material properties dynamic forming. The stress-strain curves and dynamic yield strengths under variable strain rates were obtained. Constitutive equation of 3A21 aluminium alloy was formulated by Johnson-Cook model and then, it was applied to simulate the forming behavior of 3A21 aluminum alloy tube under dynamic state by software Ansys/ls-dyna. The results show that, for magnetic pulse forming process, the simulating results well corresponded with those of experiments that demonstrate the constitutive equation established present good accuracy.

Arrhenius-Type Constitutive Equation Model of Superplastic Deformation Behaviour of Different Titanium Based Alloys

2018 ◽  
Vol 385 ◽  
pp. 45-52 ◽  
Author(s):  
Ahmed O. Mosleh ◽  
Anastasia V. Mikhaylovskaya ◽  
Anton D. Kotov ◽  
Vladimir K. Portnoy
Keyword(s):  
Strain Rate ◽  
Superplastic Deformation ◽  
Elevated Temperatures ◽  
Deformation Behaviour ◽  
Constitutive Models ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Equation Model ◽  
Flow Behaviour ◽  
Forming Process

Modelling and predicting the flow behaviour of metallic materials subjected to superplastic deformation is mandatory for providing useful information about the metal forming process. This information helps the designers to reduce the manufacturing time and costs by choosing appropriate deformation conditions based on the models results. The study developed a constitutive model to predict the flow behaviour of various Ti-based alloys (Ti-2.5Al-1.8Mn, Ti-6Al-4V and Ti-4Al-1V-3Mo) at elevated temperatures. The constant strain rate tests within the superplastic temperature and the strain rate ranges for each alloy were performed. The experimental tensile tests results were used to develop the hyperbolic sine Arrhenius-type constitutive models for each alloy. The performance of the developed model for each alloy was evaluated regarding the correlation coefficient (R), the mean absolute relative error (AARE) and the root mean square error (RMSE). The results revealed that the predicted flow stresses have a good agreement with the experimental flow stresses for the studied alloys.

The Formability and Elongation of Aluminum Alloys AA5083 and AA3003 for Micro-Truss Sandwiches Manufacturing

2020 ◽  
Vol 38 (9A) ◽  
pp. 1396-1405
Author(s):  
Arwa F. Tawfeeq ◽  
Matthew R. Barnett
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Cost Effective ◽  
Tensile Tests ◽  
Truss Structures ◽  
High Quality ◽  
Trade Off ◽  
Clad Layer ◽  
Higher Temperature ◽  
Different Shapes

The development in the manufacturing of micro-truss structures has demonstrated the effectiveness of brazing for assembling these sandwiches, which opens new opportunities for cost-effective and high-quality truss manufacturing. An evolving idea in micro-truss manufacturing is the possibility of forming these structures in different shapes with the aid of elevated temperature. This work investigates the formability and elongation of aluminum alloy sheets typically used for micro-truss manufacturing, namely AA5083 and AA3003. Tensile tests were performed at a temperature in the range of 25-500 ○C and strain rate in the range of 2x10-4 -10-2 s-1. The results showed that the clad layer in AA3003 exhibited an insignificant effect on the formability and elongation of AA3003. The formability of the two alloys was improved significantly with values of m as high as 0.4 and 0.13 for AA5083 and AA3003 at 500 °C. While the elongation of both AA5083 and AA3003 was improved at a higher temperature, the elongation of AA5083 was inversely related to strain rate. It was concluded that the higher the temperature is the better the formability and elongation of the two alloys but at the expense of work hardening. This suggests a trade-off situation between formability and strength. 

A Study on the Flow Behavior of 42CrMo Steel under Hot Compression by Thermal Physical Simulations

2010 ◽  
Vol 108-111 ◽  
pp. 494-499
Author(s):  
Ying Tong ◽  
Guo Zheng Quan ◽  
Gang Luo ◽  
Jie Zhou
Keyword(s):  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Strain Hardening Exponent ◽  
Forming Process ◽  
Material Parameters ◽  
Basic Model ◽  
42Crmo Steel ◽  
Plastic Forming ◽  
Physical Simulations

This work was focused on the compressive deformation behavior of 42CrMo steel at temperatures from 1123K to 1348K and strain rates from 0.01s-1 to 10s-1 on a Gleeble-1500 thermo-simulation machine. The true stress-strain curves tested exhibit peak stresses at small strains, after them the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. And the stress level decreases with increasing deformation temperature and decreasing strain rate. The values of strain hardening exponent n, and the strain rate sensitivity exponent m were calculated the method of multiple linear regression, the results show that the two material parameters are not constants, but changes with temperature and strain rate. Then the two variable material parameters were introduced into Fields-Backofen equation amended. Thus the constitutive mechanical discription of 42CrMo steel which can accurately describe the relationships among flow stress, temperature, strain rate, strain offers the basic model for plastic forming process simulation.

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