Eldorado Collection: 3rd International Conference on High Speed Forming3rd International Conference on High Speed Forminghttp://hdl.handle.net/2003/270252024-03-19T06:34:52Z2024-03-19T06:34:52ZAnalysis of Blank-Die Contact Interaction in Pulsed Forming ProcessesBessonov, N.Davies, R.Golovashchenko, S.http://hdl.handle.net/2003/271082015-08-12T20:53:29Z2008-01-01T00:00:00ZTitle: Analysis of Blank-Die Contact Interaction in Pulsed Forming Processes
Authors: Bessonov, N.; Davies, R.; Golovashchenko, S.
Abstract: During recent decade, significant efforts were dedicated to increasing the amount of Aluminum Alloys in automotive parts in order to reduce the net weight of cars. Processes of pulsed forming are known to expand the capabilities of traditional stamping operations. Propagation of pulsed electromagnetic field can be defined by quasi-stationary Maxwell equations, solved numerically using a non-orthogonal Lagrangian mesh. Suggested formulation included modelling of contact interaction of the blank with deformable die. Mild contact model based on introduction of acting-in-vicinity forces repelling the surfaces to be in contact was employed. It was tested by analyzing the elastic impact of bars and then was applied to the corner filling operation. This operation was analysed as a single pulse and as a multi pulse forming process. It indicated that some compromise between the blank formability enhancement and level of contact stresses on the die surface can be found. In addition, some examples of tubular parts pulsed press fitting using tube expansion with pulsed pressure were analyzed. Specific attention was paid to the analysis of factors playing important role in residual contact pressure between the exterior and interior tubes in pulsed press fitting operation.2008-01-01T00:00:00ZMagnetic Pulse Welding for Dissimilar and Similar MaterialsShribman, V.http://hdl.handle.net/2003/271072015-08-12T23:10:52Z2008-01-01T00:00:00ZTitle: Magnetic Pulse Welding for Dissimilar and Similar Materials
Authors: Shribman, V.
Abstract: The Magnetic Pulse Welding (MPW) process, a cold solid state welding process, is an industrial process, operating at several high volume manufacturing facilities. MPW is accomplished by the magnetically driven, high velocity, oblique angle, impact of two metal surfaces. At impact, the surfaces (which will always have some level of oxidation) are stripped off and ejected by the closing angle of impact. The surfaces which are then metallurgically pure, are pressed into intimate contact by the magnetic pressure, allowing valence electron sharing and atomic-level bonding. This process has been demonstrated in the joining of tubular configurations of a variety of metals and alloys [1],[2],[3]. Product designers are frequently constrained by the restrictions of traditional joining technologies, which place certain limitations on the type of joint, the materials that can be joined and the quality of the joint. Solid state welding allows manufacturers to significantly improve their product designs and production results by enabling both dissimilar and similar materials to be welded together, thus providing the opportunity to use lighter and stronger material combinations. Magnetic pulse welding is a fast, noncontact and clean solid state welding process. A review of the main elements of the process is presented here along with typical quality testing results and some applications.2008-01-01T00:00:00ZCoupling Experiment and Simulation in Electromagnetic Forming Using Photon Doppler VelocimetryBanik, K.Daehn, G. S.Fenton, G. K.Golowin, S.Henchi, I.Johnson, J. R.L Eplattenier, P.Taber, G.Vivek, A.Zhang, Y.http://hdl.handle.net/2003/271052015-08-12T20:53:25Z2008-01-01T00:00:00ZTitle: Coupling Experiment and Simulation in Electromagnetic Forming Using Photon Doppler Velocimetry
Authors: Banik, K.; Daehn, G. S.; Fenton, G. K.; Golowin, S.; Henchi, I.; Johnson, J. R.; L Eplattenier, P.; Taber, G.; Vivek, A.; Zhang, Y.
Abstract: Modeling electromagnetic forming processes is in many ways simpler than modeling traditional metal forming processes. In electromagnetic forming the problem is often dominated by inertial acceleration by a magnetic field. This is a much better posed problem than the more traditional ones that are often dominated by complex three dimensional constitutive behavior and frictional effects. However, important aspects of the problem are dominated by the constitutive properties of the material, and often electromagnetic forming is performed in a regime where there is little reliable material strength data. Strain rates are often high (102 to 104 s-1 is the typical range for electromagnetic forming). Also, heat is generated both by ohmic heating as well as by plastic deformation, and peak temperatures can be quite high. Also, while hightemperature, high-strain-rate data is scarce, there is little or no data in cases where temperature rises significantly over very short times (tens of micro-seconds) as happens in electromagnetic metal forming. This rapid temperature rise is very important to the material response because the short time scales largely preclude the material from recovery and recrystallization processes and precipitates cannot dissolve as they normally would in an age-hardening alloy in these time scales. This presentation will show how advanced instrumentation, particularly the Photon Doppler Velocimeter (PDV) can be coupled with electromagnetic forming and provide both avenues to characterize material as well as to provide very critical tests of numerical models of the process.2008-01-01T00:00:00ZProduction of Steel-Light Metal Compounds with Explosive Metal CladdingKoschlig, M.Raabe, D.Veehmayer, M.http://hdl.handle.net/2003/271062015-08-12T20:53:37Z2008-01-01T00:00:00ZTitle: Production of Steel-Light Metal Compounds with Explosive Metal Cladding
Authors: Koschlig, M.; Raabe, D.; Veehmayer, M.
Abstract: Explosive Metal Cladding is a High Speed Welding Process using the energy of an
explosive to bond different metals and alloys in a 2-dimensinal areal configuration. Parameters influencing the cladding process are discussed and the potentials of the method are presented. Microscopic properties of a Cu-Al and a Steel-Ti transition zone are studied in detail to get a better knowledge of the principle mechanisms included in the bond creation. A perspective for future applications of explosive cladding in different industries like automotive and aerospace is given.2008-01-01T00:00:00ZElectromagnetic Compressive Split Hopkinson BarMartins, P. A. F.Rosa, P. A. R.Silva, C. M. A.http://hdl.handle.net/2003/271042015-08-12T20:53:33Z2008-01-01T00:00:00ZTitle: Electromagnetic Compressive Split Hopkinson Bar
Authors: Martins, P. A. F.; Rosa, P. A. R.; Silva, C. M. A.
Abstract: This paper proposes a new design for the compressive split Hopkinson bar that makes use of the intense pressure created in a transient magnetic field formed by the passage of a pulse of electric current through a series of coils. The proposed technology enables to characterize the behaviour of materials under high strain-rates with a small acceleration path length of the striker bar and, because propulsion is purely electromagnetic, the overall performance can be easily controlled and nearly infinitely adjustable. The presentation is focused on the design and fabrication of the mechanical, electrical and electromagnetic components of the new compressive split Hopkinson bar and includes results from two different testing applications to demonstrate the validity of the proposed concept.2008-01-01T00:00:00ZInfluence of Forming Rate on the Microstructure and Properties of Materials Subjected to Electromagnetic FormingBach, F.-W.Bormann, D.Walden, L.http://hdl.handle.net/2003/271032015-08-12T20:53:23Z2008-01-01T00:00:00ZTitle: Influence of Forming Rate on the Microstructure and Properties of Materials Subjected to Electromagnetic Forming
Authors: Bach, F.-W.; Bormann, D.; Walden, L.
Abstract: Electromagnetic high speed forming has been known since the 1960's and is successfully used for frictional connexions. In addition to joining, other applications of the process include coining, stamping and cutting. Regarding product quality and manufacturing costs, the process is superior to other methods and yet its utilisation can still be extended.
The synopsis of the material's microstructure and properties owing to electromagnetic forming, which is given by this article, clarifies the processes from a materials science point of view. This will not only represent an academic view point but also provide insight into a potential expansion of the process to other areas of application.2008-01-01T00:00:00ZThe Mechanical Behaviour of Ultra Fine Grained Titanium Alloys at High Strain RatesHalle, T.Herzig, N.Krüger, L.Meyer, L. W.Musch, D.Razorenov, S. V.Skripnyak, E. G.Skripnyak, V. A.http://hdl.handle.net/2003/271022015-08-12T20:53:48Z2008-01-01T00:00:00ZTitle: The Mechanical Behaviour of Ultra Fine Grained Titanium Alloys at High Strain Rates
Authors: Halle, T.; Herzig, N.; Krüger, L.; Meyer, L. W.; Musch, D.; Razorenov, S. V.; Skripnyak, E. G.; Skripnyak, V. A.
Abstract: Within this study the mechanical behaviour of ultra-fine grained Ti-6-22-22S titanium alloy was investigated and compared to coarse grained material. By severe plastic deformation using the cyclic channel die compression process, grain sizes between 300 and 500 nm were obtained. The mechanical behaviour was studied over a wide range of strain rates from 10^(-3) - 107 s^(-1) under compressive loading using different experimental techniques. A significant increase of flow stress with decreasing grain size compared to the coarse grain state was found. An evaluation of the strain hardening behaviour of the UFG material shows a significant increase of the strain hardening coefficient at high strain rates for low plastic deformation. The strain rate sensitivity of the material is found to be constant within a range of strain rates from 10^(-3) to 106 s^(-1) but increases at higher plastic strains. However, compressive deformability is nearly constant up to 102 s-1 and decreased disproportionately at higher rates of strain. With decreasing grain size a significant decrease of compressive deformability was found. The strength at failure is increased with increasing strain rate.2008-01-01T00:00:00ZFailure Elongation of Steel Sheets for an Autobody at the High Strain RateHuh, H.Kim, S. B.Lim, J. H.Song, J. H.Yoon, J. H.http://hdl.handle.net/2003/271012015-08-12T20:53:13Z2008-01-01T00:00:00ZTitle: Failure Elongation of Steel Sheets for an Autobody at the High Strain Rate
Authors: Huh, H.; Kim, S. B.; Lim, J. H.; Song, J. H.; Yoon, J. H.
Abstract: This paper presents the dynamic failure elongation of conventional mild steels and advanced high strength steel sheets such as TRIP and DP steels. The failure elongation has been obtained from the high speed tensile testing machine with various strain rates ranged from 0.003/s to 200/s. The experimental result demonstrates that the tensile elongation does not simply decrease as the strain rate increases, but it decreases from the quasi-static state to the strain rate of 0.1 or 1/s and increases again up to the strain rate of 100/s. Furthermore, some high strength steels have the tendency that the tensile elongation increases as the strain rate increases. This tendency has varieties depending on the microstructure and forming history of sheet metal. Moreover, the localized strain rate hardening in the necking region induces the increase of elongation. This phenomenon is very important not only in sheet metal forming but also in the crashworthiness evaluation to predict the fracture of sheet metal members.2008-01-01T00:00:00ZIntroduction of an Electromagnetism Module in LS-DYNA for Coupled Mechanical Thermal Electromagnetic SimulationsAshcraft, C.Cook, G.L Eplattenier, P.http://hdl.handle.net/2003/271002015-08-12T20:53:27Z2008-01-01T00:00:00ZTitle: Introduction of an Electromagnetism Module in LS-DYNA for Coupled Mechanical Thermal Electromagnetic Simulations
Authors: Ashcraft, C.; Cook, G.; L Eplattenier, P.
Abstract: A new electromagnetism module is being developed in LS-DYNA for coupled mechanical/thermal/electromagnetic simulations. One of the main applications of this module is Electromagnetic Metal Forming. The electromagnetic fields are solved using a Finite Element Method for the conductors coupled with a Boundary Element Method for the surrounding air/insulators. Both methods use elements based on discrete differential forms for improved accuracy. The physics, numerical methods and capabilities of this new module are presented in detail as well as its coupling with the mechanical and thermal solvers of LS-DYNA. This module is then illustrated on an Electromagnetic Metal Forming case.2008-01-01T00:00:00ZNumerical Modelling of High Speed Blanking Considering Thermoviscoplastic EffectsBehrens, B.-A.Peshekhodov, I.Sidhu, K. B.http://hdl.handle.net/2003/270992015-08-12T20:53:09Z2008-01-01T00:00:00ZTitle: Numerical Modelling of High Speed Blanking Considering Thermoviscoplastic Effects
Authors: Behrens, B.-A.; Peshekhodov, I.; Sidhu, K. B.
Abstract: To achieve the required specifications of the cut-edge profile of a blank, a time consuming trial and error procedures based on empirical information are utilized. However, the modern industry demands high quality product specifications in the shortest possible production time. Therefore, in order to predict the cut-edge profile and speed up the production process, it is essential to develop a reliable numerical model of the high speed blanking process which can predict the cut-edge profile of the blanks. In this study, the Lagrangian based finite element (FE) approach was used to model large strain deformation that takes place in the shearzone during blanking. However, the large deformation is difficult to model using Lagrangian approach as it leads to a severe distortion of the FE mesh. Therefore, in order to overcome a premature termination of the analysis due to the mesh distortion, an adaptive remeshing and rezoning technique was developed. Furthermore, to model the ductile fracture, the discrete crack propagation method was implemented in the MSC.Marc® Due to high speed of the cutting stamp, thermoviscoplastic material behaviour has to be taken into account. The Johnson-Cook plasticity model was used to model viscoplasticity. The results obtained from the FE analysis are presented in this paper.2008-01-01T00:00:00ZModeling and Simulation of 3D EMF ProcessesBlum, H.Reese, S.Schwarze, M.Stiemer, M.Svendsen, B.Unger, J.http://hdl.handle.net/2003/270982015-08-12T20:53:53Z2008-01-01T00:00:00ZTitle: Modeling and Simulation of 3D EMF Processes
Authors: Blum, H.; Reese, S.; Schwarze, M.; Stiemer, M.; Svendsen, B.; Unger, J.
Abstract: A recent interest in potential industrial applications of electromagnetic forming processes has inspired a demand for adequate simulation tools. Aiming at the virtual design of industrial applications, the purpose of this work is to develop algorithmic formulations particularly suitable to reduce the enormous computational cost inherent to 3D simulations. These formulations comprise a carefully chosen discretization, highly accurate methods for data transfer between electromagnetic and mechanical subsystems, an efficient solid shell formulation, and a termination criterion for the electromagnetic field computation. As a result the simulation time is reduced by about one order of magnitude.2008-01-01T00:00:00ZModels for Electromagnetic Metal FormingBartels, G.Leone, M.Schätzing, W.Scheibe, H. P.http://hdl.handle.net/2003/270972015-08-12T20:53:44Z2008-01-01T00:00:00ZTitle: Models for Electromagnetic Metal Forming
Authors: Bartels, G.; Leone, M.; Schätzing, W.; Scheibe, H. P.
Abstract: This paper presents a comparison of different simulation options for electromagnetic metal forming in order to make preliminary investigations with adequate accuracy. Four simulation models are compared. The models mainly differ in their complexity, handling and necessary precondition program packages. The user has the choice to use a simple program with a defined program algorithm or to use a program with a higher programming complexity which accepts more information.2008-01-01T00:00:00ZFast Algorithms for the Simulation of Electromagnetic Metal FormingBlum, H.Stiemer, M.Svendsen, B.Unger, J.http://hdl.handle.net/2003/270962015-08-12T20:54:01Z2008-01-01T00:00:00ZTitle: Fast Algorithms for the Simulation of Electromagnetic Metal Forming
Authors: Blum, H.; Stiemer, M.; Svendsen, B.; Unger, J.
Abstract: Despite the comprehensive understanding of the modeling and numerical simulation of electromagnetic metal forming that has recently been gained, the simulation of real forming situations is still a challenging task due to the large computational resources required. A bottleneck is the computation of the electromagnetic fields, since 100.000 up to several million unknowns are required to represent the geometry of a typical forming device. The purpose of this article is to present new techniques to speed up the simulation of electromagnetic metal forming with particular emphasis on the computation of the electromagnetic fields. An acceleration of the electromagnetic field computation is a significant step towards a virtual design of electromagnetic forming processes.2008-01-01T00:00:00ZModelling of the Mechanical Behaviour of Ultra-Fine Grained Titanium Alloys at High Strain RatesHalle, T.Herzig, N.Krüger, L.Meyer, L. W.Musch, D.Razorenov, S. V.Skripnyak, E. G.Skripnyak, V. A.http://hdl.handle.net/2003/270952015-08-12T20:53:52Z2008-01-01T00:00:00ZTitle: Modelling of the Mechanical Behaviour of Ultra-Fine Grained Titanium Alloys at High Strain Rates
Authors: Halle, T.; Herzig, N.; Krüger, L.; Meyer, L. W.; Musch, D.; Razorenov, S. V.; Skripnyak, E. G.; Skripnyak, V. A.
Abstract: Results of numerical simulations of the mechanical behaviour of coarse grained and UFG titanium alloys under quasi-static uniaxial compression and plane shock wave loading are presented in this paper. Constitutive equations predict the strain hardening behaviour, the strain rate sensitivity of the flow stress and the temperature softening of titanium alloys with a range of grain sizes from 20 µm to 100 nm. Characteristics of the mechanical behaviour of UFG a and a+ß titanium alloys in wide range of strain rates are discussed.2008-01-01T00:00:00ZFlanging and Hemming of Auto Body Panels using the Electro Magnetic Forming technologyAnderson, R.Brännström, P.Daehn, G. S.Eguia, I.Gonzalez, B.Gutierrez, M. A.Jimbert, P.Olsson, S. O.Sundberg, H.Zhang, Y.http://hdl.handle.net/2003/270932015-08-12T23:44:12Z2008-01-01T00:00:00ZTitle: Flanging and Hemming of Auto Body Panels using the Electro Magnetic Forming technology
Authors: Anderson, R.; Brännström, P.; Daehn, G. S.; Eguia, I.; Gonzalez, B.; Gutierrez, M. A.; Jimbert, P.; Olsson, S. O.; Sundberg, H.; Zhang, Y.
Abstract: Electro Magnetic Forming (EMF) technology has a great number of potential applications for the automotive industry. LABEIN-Tecnalia has worked with this technology for six years and has a good understanding of the automotive industry s needs and challenges. LABEIN-Tecnalia is currently developing new applications with EMF technology. Taking into account the advantages and limitations of EMF, bending and hemming processes present good geometric conditions for the use of this technology. The study presented is based largely on hemming circular configurations which are simplifications of those commonly used on hemmed automotive parts. The parameters of this new EMF bending and hemming processes have been studied, as well as their influence on the final quality of the parts obtained. Conclusions obtained from the basic geometries were tested on a more complicated geometry in order to apply the knowledge acquired. Parallel to the experimental work, fully coupled electromechanical software by LS-DYNA has been used to simulate and extend the present hemming results.2008-01-01T00:00:00ZTowards the Contact and Impact Modeling in Finite Element Simulations of High Speed FormingReese, S.Rickelt, C.Schwarze, M.http://hdl.handle.net/2003/270942015-08-12T20:53:21Z2008-01-01T00:00:00ZTitle: Towards the Contact and Impact Modeling in Finite Element Simulations of High Speed Forming
Authors: Reese, S.; Rickelt, C.; Schwarze, M.
Abstract: In finite element simulations of high speed sheet metal forming processes the contact between workpiece and forming tools has to be modeled very carefully. Several important aspects have to be taken into account. Robust and locking-free finite element formulations are required to model the sheet forming process, the die has to be considered as a deformable component, and the description of the contact constraints between workpiece and forming tools is a significant source of shortcomings in modeling. The contact and impact simulation makes high demands on the robustness of finite element formulations. For this reason finite elements with low order ansatz functions are preferred. Furthermore, they prove to be advantageous when automatic meshing tools are applied. To overcome the undesired effects of locking we work with an improved version of the innovative solid-shell concept proposed by [11]. It is based on the concept of reduced integration with hourglass stabilization. The use of this solid-shell finite element allows us to test the influence of the modeling of the die and the contact constraints in a very efficient way. An overview of so-called macro and micro deformations of forming tools in sheet metal forming simulations can be found in [8]. We show that the deformation of the die has a noticeable influence in electromagnetic sheet metal forming. However, in most commercial finite element codes taking into account elastically deformable forming tools requires a full finite element discretization of the die which leads to very high computational effort. Therefore users often assume the tools as being rigid and apply node-based spring-dashpot systems to improve the modeling of the interaction between sheet metal and die. But also in this case local interactions cannot be taken into account realistically. As a possible remedy we investigate a fully elastic description of the forming tools in combination with model reduction techniques. These significantly reduce the number of degrees-of-freedom in the finite element simulation. For this reason we present different alternatives of this technique.2008-01-01T00:00:00ZResearch in Impulse Joining of Self Pierce RivetingHahn, O.Kraus, C.Leuschen, G.Mauermann, R.Neugebauer, R.http://hdl.handle.net/2003/270922015-08-12T20:53:15Z2008-01-01T00:00:00ZTitle: Research in Impulse Joining of Self Pierce Riveting
Authors: Hahn, O.; Kraus, C.; Leuschen, G.; Mauermann, R.; Neugebauer, R.
Abstract: Results are shown in impulse joining of aluminium sheets with self-pierce-riveting. Two institutes are testing impulse-riveting with different setting velocities of the punch up to 10 m/s by using pneumatic cylinders and about 100 m/s by using a propellant charge. One aim focus consists in riveting without a C-frame against a flat anvil instead of using a C-frame with a contoured die. So accessibility is increased and disadvantages of occurring misalignments are avoidable.
The strength properties of the realised joints are tested.2008-01-01T00:00:00ZElectromagnetic Forming of AZ31B Magnesium Alloy SheetArroyo, A.Hurtado, I.Imbert, J.Salisbury, C. P.Ulacia, I.Worswick, M. J.http://hdl.handle.net/2003/270902015-08-13T01:06:27Z2008-01-01T00:00:00ZTitle: Electromagnetic Forming of AZ31B Magnesium Alloy Sheet
Authors: Arroyo, A.; Hurtado, I.; Imbert, J.; Salisbury, C. P.; Ulacia, I.; Worswick, M. J.
Abstract: In the first stage of this work, polycrystalline specimens of AZ31B magnesium alloy have been characterized by uniaxial tensile tests at quasi-static and dynamic strain rates at room temperature. The influence of the strain rate is outlined and experimental results were fitted to the parameters of Johnson-Cook constitutive material model. In the second stage of the present study, sheets of AZ31B magnesium alloy have been biaxially formed by electromagnetic forming using different coil and die configurations. Deformation values measured from electromagnetic formed parts are compared to the ones achieved with uniaxial tensile tests and also with the values obtained by conventional forming technologies. Finally, numerical simulations have been carried out using an alternative method for computing the electromagnetic fields in the EMF process simulation, a combination of Finite Element Method (FEM) for conductor parts and Boundary Element Method (BEM) for the surrounding air (or more generally insulators) that is being implemented into commercial code LS-DYNA®.2008-01-01T00:00:00ZProcess Analysis and Physical Simulation of Electromagnetic Joining of Thin-Walled partsBach, F.-W.Brosius, A.Demir, O. K.Gershteyn, G.Psyk, V.Schaper, M.Tekkaya, A. E.http://hdl.handle.net/2003/270912015-08-13T01:50:39Z2008-01-01T00:00:00ZTitle: Process Analysis and Physical Simulation of Electromagnetic Joining of Thin-Walled parts
Authors: Bach, F.-W.; Brosius, A.; Demir, O. K.; Gershteyn, G.; Psyk, V.; Schaper, M.; Tekkaya, A. E.
Abstract: To avoid typical problems when connecting different metallic materials as aluminum and titanium as e.g. the formation of intermetallic phases, electromagnetic welding represents an alternative technology to conventional (i.e. usually thermal) joining processes. Although feasibility and potential of this technique are already proved, the fundamental correlations of part- and process-parameters have not yet been investigated systematically. As an approach to examine these, the performance of model experiments and supplementary technological tests is suggested. The resulting connection quality is evaluated using metallographic methods.2008-01-01T00:00:00ZDesign and Analysis of a Deep Drawing and Inprocess Electromagnetic Sheet Metal Forming ProcessBach, F.-W.Beerwald, C.Brosius, A.Dudzinski, W.Gersteyn, G.Risch, D.Schaper, M.Tekkaya, A. E.http://hdl.handle.net/2003/270892015-08-12T20:54:05Z2008-01-01T00:00:00ZTitle: Design and Analysis of a Deep Drawing and Inprocess Electromagnetic Sheet Metal Forming Process
Authors: Bach, F.-W.; Beerwald, C.; Brosius, A.; Dudzinski, W.; Gersteyn, G.; Risch, D.; Schaper, M.; Tekkaya, A. E.
Abstract: The design as well as the subsequent analysis of a deep drawing and in-process
electromagnetic sheet metal forming calibration will be described in this paper. Due to the quite different forming processes concerning the occurred strain rates, an investigation on the microstructure of the formed workpieces will be pointed out. Furthermore, the design steps regarding the integrated tool coil will be presented and the resulting examples discussed. Finally, the setup of the integrated process as well as the feasibility will be shown on an exemplary semi-industrial workpiece.2008-01-01T00:00:00ZForming Behaviour in Laser Shock DrawingSchulze Niehoff, H.Vollertsen, F.Wielage, H.http://hdl.handle.net/2003/270882015-08-13T02:15:20Z2008-01-01T00:00:00ZTitle: Forming Behaviour in Laser Shock Drawing
Authors: Schulze Niehoff, H.; Vollertsen, F.; Wielage, H.
Abstract: Through the continuing trend of miniaturization new cost efficient and fast methods for processing small parts are required. In this paper a new non-mechanical process for the forming process of micro deep drawing is presented. This new deep drawing process utilizes a laser initiated plasma shock wave at the target, which forms the sheet. Several pulses can be applied at one point and therefore high forming degrees can be reached without increasing the energy density. In this paper the pressure of the shock wave is measured in order to enable optimizations of the process in future. Furthermore a distribution of the thickness over the deep drawn cups will be introduced. Finally laser deep drawing of samples made out of Al99.5, Cu and stainless steel sheet metal with thicknesses of 20 µm and 50 µm are shown.2008-01-01T00:00:00ZAction of Pulse-Magnetic Fields on Liquid and Crystallizing MetalChernikov, D. G.Glouschenkov, V. A.Grechnikov, F. V.Igolkin, A. J.Jusupov, R. J.http://hdl.handle.net/2003/270872015-08-12T23:09:01Z2008-01-01T00:00:00ZTitle: Action of Pulse-Magnetic Fields on Liquid and Crystallizing Metal
Authors: Chernikov, D. G.; Glouschenkov, V. A.; Grechnikov, F. V.; Igolkin, A. J.; Jusupov, R. J.
Abstract: Pulsed-magnetic fields are used for execution of a whole complex of technological processes: dividing, forming, assembling, welding and others. In all these technologies half-finished products from sheets, sections and tubes are used as billets. Action of magnetic fields on a cast metal is known in the metallurgy production, for example, casting to an electromagnetic crystallizer. In spite of a high electrical resistance of a melt and owing to low mechanical resistance of a liquid metal the use of high-intensity pulse-magnetic fields (PMF) in technologies of mechanical engineering is of interest. Even the first exploration experiment showed high efficiency of such action. At energy of 1, 2 kJ a portion of the melt under the action of the PMF has flown more than 4 m, spread in the form of a thin film on the ceiling and solidified. The paper presents three basic technological schemes of such action: with influence through a wall of a magneto-transparent crucible; by an immersion inductor; and action from the surface. Factors accompanying such action are: added sources of heat as a result of flowing of induced eddy currents through the melt; force action on the melt responsible for passage of waves of stress and metal flows. Action of these factors is controllable both in intensity and in direction. The temporal action of the pulse-magnetic field on a liquid and crystallizing metal (LCM) is to be matched with a curve of cooling the melt: either on the portion above the crystallization area or on its different portions, that is, at different relationships of solid and liquid phases.Factors of action of the pulse-magnetic field change temperature conditions of crystallization influence on the number of centers of crystallization and, as the consequence, change structure and properties of cast metal. The paper presents results of first studies on action of the pulse-magnetic field on a LCM which testify that such action is real and good. This has determined the prospects for development of new technologies in metallurgy (forming of an ingots structure, stirring of a material, rolling of cast metal and so on) and in mechanical engineering (in casting, stamping, welding and others).2008-01-01T00:00:00ZElectromagnetic Pulse Forming of Carbon Steel Sheet MetalAndersson, R.Syk, M.http://hdl.handle.net/2003/270862015-08-12T20:53:35Z2008-01-01T00:00:00ZTitle: Electromagnetic Pulse Forming of Carbon Steel Sheet Metal
Authors: Andersson, R.; Syk, M.
Abstract: Electromagnetic pulse forming is a promising direct method for a high speed sheet metal forming of materials with high conductivity, like Al- and Cu-alloys. For metallic sheet with low conductivity, like carbon steel sheets, the frequency of the current through the forming coil must increase to create the same forming properties as for materials with high conductivity. Usually this frequency is not easy to change in an existing electromagnetic pulse system without exchanging of the capacitors. Anyway, this project have analysed the formability of two high strength steel sheet material, a carbon steel DP60 and a austenitic stainless steels, with and without a copper driver. The experiments were made on commercial electromagnetic pulse system from Poynting with a predefined current frequency through the forming coil. The geometries that were used for the electromagnetic pulse forming analysis were a cone, rectangular parts, and spherical dome. All physical parts were 3D digitised and the deviation were analysed against nominal reference objects. The spherical dome experiment was used to analyse the increase in formability of the high strength steel sheets compared with conventional stamping in an Erichsén sheet metal testing machine.2008-01-01T00:00:00ZInfluence of Mandrel s Surface on the Mechanical Properties of Joints Produced by Electromagnetic CompressionBarreiro, P.Brosius, A.Hammers, T.Löhe, D.Marré, M.Rautenberg, J.Schulze, V.Tekkaya, A. E.http://hdl.handle.net/2003/270852015-08-12T20:53:40Z2008-01-01T00:00:00ZTitle: Influence of Mandrel s Surface on the Mechanical Properties of Joints Produced by Electromagnetic Compression
Authors: Barreiro, P.; Brosius, A.; Hammers, T.; Löhe, D.; Marré, M.; Rautenberg, J.; Schulze, V.; Tekkaya, A. E.
Abstract: Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for the manufacturing of lightweight structures. Taking conventional interference fits into account, the contact area s influence on the joint s quality seems to be of significance, as e.g. the contact area and the friction coefficient between the joining partners determine an allowed axial load or torsional momentum proportionally. Therefore, different contact area surfaces were prepared by shot peening and different machining operations and strategies. The mandrel s surfaces were prepared by shot peening with glass beads and Al2O3 particles. Alternatively, preparation was done using simultaneous five axis milling, because potential joining partners in lightweight frame structures within the Transregional Collaborative Research Centre SFB/TR10 would be manufactured similarly. After that, the manufactured surfaces were characterized by measuring the surface roughness and using confocal whitelight microscopy. After joining by electromagnetic compression, the influence of different mandrel s surface conditions on the joint s mechanical properties were analyzed by tensile tests. Finally, conclusions and design rules for the manufacturing of joints by electromagnetic compression are given.2008-01-01T00:00:00ZCorrosion Protection of the Zone of Thermal Action (Zone of Butt of Tubes While Welding) from the Inside When Laying Multifunctional Pipeline SystemsGlouschenkov, V. A.Karpukhin, V. F.http://hdl.handle.net/2003/270842015-08-12T20:53:17Z2008-01-01T00:00:00ZTitle: Corrosion Protection of the Zone of Thermal Action (Zone of Butt of Tubes While Welding) from the Inside When Laying Multifunctional Pipeline Systems
Authors: Glouschenkov, V. A.; Karpukhin, V. F.
Abstract: The work is aimed at handling a main problem of corrosion protection of the pipeline s interior section adjacent to a weld butt. It is proposed to execute fastening of elements of the protective system of pipes by application of the pulse-magnetic technology which has essential technical and economical advantages over other methods. Protection of end sections of pipes is performed by pulse-magnetic pressing-in of a bush made from stainless steel or by pulse-magnetic welding of rings from a protective material. Commercial tests of the pipelines produced by the technology being proposed supported good prospects of this technology use.2008-01-01T00:00:00ZReversed Switch-On Dynistor Switches of Gigawatt Power Microsecond PulsesAristov, Y. V.Grekhov, I. V.Korotkov, S. V.Kozlov, A. K.Lyublinsky, A. G.http://hdl.handle.net/2003/270822015-08-12T20:53:38Z2008-01-01T00:00:00ZTitle: Reversed Switch-On Dynistor Switches of Gigawatt Power Microsecond Pulses
Authors: Aristov, Y. V.; Grekhov, I. V.; Korotkov, S. V.; Kozlov, A. K.; Lyublinsky, A. G.
Abstract: A high-power (250 kA and 25 kV) compact switch based on an assembly of reversed switch-on dynistors (RSDs) connected in series and a coaxial saturable-core choke, which is necessary for their effective switching, is described. An essential feature of this switch is a drastic reduction of the duration of RSDs control pulse, which allows using minimum dimensions and low inductance saturable core choke and obtain high rise rate (more than 30 kA/µs) of the switched current. The increased RSDs control pulse amplitude and rise rate that are required for RSDs switching on by reduced duration triggering pulse are attained by using a fast switch based on new type semiconductor devices deep-level dynistors (DLDs).2008-01-01T00:00:00ZHigh-current Capability of Coaxial Cables in Magnetoforming ApplicationsHartmann, W.Pohl, F.Römheld, M.http://hdl.handle.net/2003/270832015-08-12T20:53:31Z2008-01-01T00:00:00ZTitle: High-current Capability of Coaxial Cables in Magnetoforming Applications
Authors: Hartmann, W.; Pohl, F.; Römheld, M.
Abstract: Magnetoforming technology often requires impulse current amplitudes of several hundred kiloamps, at pulse durations between 30 µs and > 100 µs. Often, it is required to provide the impulse via a flexible transmission line (cable) in order to allow the forming coil to be positioned correctly. These cables have to withstand the high pulse currents without deterioration for a large number of pulses. In addition, it is necessary to minimise the inductance of the cable connection, as an increase in inductance negatively influences the efficiency of the installation as a whole, whence low-inductance coaxial cables are required which are able to fulfil all of these requirements simultaneously. Manufacturers normally do not specify the impulse current capability of coaxial cables, as this is not necessary for most standard applications. Therefore, experiments were performed to explore the limits of commercial medium high voltage cables in regard of their impulse current withstand capability for these specific impulse parameters. A coaxial medium voltage cable has been tested at single pulses of ca. 100 µs duration, at amplitudes between 30 and 140 kA. The radial deformation (expansion) of the cable was detected with a high-resolution, high-speed camera. At a frame rate of 9000 frames/s the expansion of the cable has been determined as a function of the current amplitude. We observed dynamic changes of the cable diameter at currents above 81 kA, reaching up to 1.26 mm increase in diameter at 142 kA pulse amplitude. Above 100 kA, part of the deformation becomes irreversible, with cumulated permanent changes of up to 1 mm. The measurements are used to estimate the operating range of these cables.2008-01-01T00:00:00ZAssessing the Effective Energy for Magnetic Forming Processes by Means of Measurements and Numerical CalculationKulig, S.Peier, D.Rosendahl, J.Werdelmann, P.http://hdl.handle.net/2003/270812015-08-12T20:54:09Z2008-01-01T00:00:00ZTitle: Assessing the Effective Energy for Magnetic Forming Processes by Means of Measurements and Numerical Calculation
Authors: Kulig, S.; Peier, D.; Rosendahl, J.; Werdelmann, P.
Abstract: The efficiency of magnetic sheet metal forming processes is strongly depending on the facility s overall design. This mainly includes the geometric layout of forming tool, work piece and matrix but, however, will also expect the energy storage device being taken into consideration. Apart from field theoretic models the energy storage is describable by its terminal traits which the electric load - tool coil and work piece - is connected to. The paper presents a measuring method for the tool coil s terminal quantities, current i(t) and voltage u(t), which are used to provide the electric power p(t) being transferred to the load. Thus, it is possible to determine the entire energy which is dissipated by the work piece, provided that the coil s resistance is known. Besides the measurement, this approach is supported by numerical calculation intending to take a closer look at the inner losses of the work piece which are not accessible from measuring the system s terminal traits directly. Dividable into separate parts of the total energy, this information is applied to assess the forming process by means of the facility s energetic performance and to draw an overall energy balance.2008-01-01T00:00:00ZReliability of Solid State Switches Used in High Current Discharge ApplicationsBacklund, B.Welleman, A.http://hdl.handle.net/2003/270802015-08-12T20:53:55Z2008-01-01T00:00:00ZTitle: Reliability of Solid State Switches Used in High Current Discharge Applications
Authors: Backlund, B.; Welleman, A.
Abstract: The presentation will give information about the long term reliability of semiconductor components which are used in high current, high di/dt discharge switches as they are used in systems for electro-magnetic forming. Prototype equipment for laboratory use has shown the capability of the switches and equipment to fulfil the requirements requested by the end-users. This however is not enough to be used in the industrial production lines under continuous and repetitive heavy load conditions. Because of the relative high lifetime expectations of the durable equipment used for magnetic forming in the automotive industry the life-time of the semiconductor switches, the inductive loads and the capacitor banks are becoming an issue. The presentation will only describe the semiconductor reliability. A prototype system for 21 kVdc and pulse current of 210 kA was designed and built in the year 2005 by Siemens for the Fraunhofer Institute in Chemnitz, Germany. The semiconductor switch was supplied by ABB Switzerland Ltd. For this experimental machine only low repetition rates of one shot per several minutes and a limited expected life-time of approx. 15.000 20.000 shots was acceptable for the experimental work. The requirement from the automotive industry however is at least one shot per 15 seconds and an operational life-time of >= 2 Mio shot at the mentioned power level. During the last year ABB has done extensive tests to evaluate the behaviour of the semiconductor components used in high current solid state switches under the specific application conditions for production processes. In the presentation the test results of high current semiconductor devices are described for 250.000 shots and 1 Mio shots, and recommendations for reliable solid state switch designs are given. Keywords Semiconductor2008-01-01T00:00:00ZNovel Layers for Dies Used in Electromagnetic Sheet Metal Forming ProcessesBrosius, A.Hoffmann, F.Nebel, J.Risch, D.Tekkaya, A. E.Tillmann, W.Vogli, E.http://hdl.handle.net/2003/270792015-08-12T20:53:50Z2008-01-01T00:00:00ZTitle: Novel Layers for Dies Used in Electromagnetic Sheet Metal Forming Processes
Authors: Brosius, A.; Hoffmann, F.; Nebel, J.; Risch, D.; Tekkaya, A. E.; Tillmann, W.; Vogli, E.
Abstract: Due to the high forming velocities during electromagnetic sheet metal forming processes, a high impact force acts between workpiece and die. Here, the die surface sustains high damages shown by high wear and galling of the workpiece on the die surface. To enhance the die lifetime, a novel coating concept based on the PVD (physical vapour deposition) process was developed. In doing so, the hardness and the toughness of the designed layers were varied and adjusted to the demands of AlMg-sheet forming process.2008-01-01T00:00:00Z3rd International Conference on High Speed FormingKleiner, M.Tekkaya, A. E.http://hdl.handle.net/2003/251582016-02-02T15:58:46Z2008-03-11T00:00:00ZTitle: 3rd International Conference on High Speed Forming
Authors: Kleiner, M.; Tekkaya, A. E.2008-03-11T00:00:00Z