Verena Psyk

Integration of Electromagnetic Calibration into the Deep Drawing Process of an Industrial Demonstrator Part

In recent years a steadily growing interest in applying lightweight construction concepts could be observed. This development is accompanied by an increasing demand for innovative forming strategies suitable for extending the forming limits of the typical lightweight materials. Deep drawing combined with an integrated electromagnetic calibration step is an example of such a technology. The feasibility and potential of this process combination is analyzed on the basis of a demonstrator part from the automotive industry. Thereby, aspects related to the practicability of the electromagnetic forming process itself are regarded as well as points related to the deep drawn preform. The concept of a 3D-coil insert, integrated into a deep drawing punch in order to realize the calibration in the deep drawing process, is introduced and based on the experimental results, conclusions regarding the applicability of the process combination are drawn.

Process Analysis and Physical Simulation of Electromagnetic Joining of Thin-Walled parts

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 partand 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.

Simulation of tube wrinkling in electromagnetic compression

Wrinkle formation at electromagnetic tube compression was simulated using finite element (FE) method. Three-dimensional (3D) calculations were performed using a staggered coupling scheme between the electromagnetic and structural sides of the problem. Introducing the tube’s contour imperfections into the FE model makes the simulation of the wrinkle formation possible. The results show good correspondence with the experiments.

Investigation on a Deep Drawing and In-Process Electromagnetic Calibration

Extending forming limits is one of the most important aims of research work in production engineering. One possibility to improve material formability is the application of high strain rates, which can be realized e.g. by means of electromagnetic forming (EMF). A further extension of the forming limits can be achieved by a beneficial combination of EMF and quasistatic forming operations, which allow exploiting the complementary advantages of the different technologies involved. This approach will be described on the basis of a deep drawing and inprocess electromagnetic sheet metal forming calibration in this paper. Thereby, the design as well as the subsequent analysis of the components as well as the combined process plays a distinctive role. Furthermore, the stages of development 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.

A drop-weight high-speed tensile testing instrument

A drop-weight high-speed tensile testing instrument was developed, in which the acting force and the specimen elongation can be obtained by measuring the displacement of the drop-weight by means of an opto-electronic transducer. The system was used to obtain the flow curves of AA5754 at strain rates up to 2,200xa0s−1. The flow curves were verified with the help of finite element calculations by comparing the displacement and full-field strain measurement results. The developed instrument provides satisfying flow curves, in addition to being simple and cheap.

Numerical Method to Analyze Local Stiffness of the Workpiece to avoid Rebound During Electromagnetic Sheet Metal Forming

Electromagnetic sheet metal forming is a high speed forming process using pulsed magnetic fields to form metals with high electrical conductivity such as aluminum. Thereby, workpiece velocities of more than 300 m/s are achievable, which can cause difficulties when forming into a die: the kinetic energy, which is related to the workpiece velocity, must dissipate in a short time slot when the workpiece hits the die; otherwise undesired effects, for example rebound, can occur. One possibility to handle this shortcoming is to locally increase the stiffness of the workpiece. In order to be able to estimate the local stiffness a method is presented which is based on a modal analysis by means of the Finite‐Element‐Method. For this reason, it is necessary to fractionize the considered geometries into a part‐dependent number of segments. These are subsequently analyzed separately to determine regions of low geometrical stiffness. Combined with the process knowledge concerning the velocity distribution within the w...