Authors: Brosius, A.
Kleiner, M.
Title: Determination of Material Characteristics using Electromagnetic Forming and Weak Coupled Finite Element Simulations
Language (ISO): en
Abstract: The aim of this approach is to determine material characteristics of aluminium alloys (in the present case: AA5747) at very high strain rates, more precisely the relationship between yield stress, plastic strain and strain rate is figured out. To achieve high strain rates up to 10^4 s^(-1) the electromagnetic forming process (EMF) is applied, where a pulsed magnetic field is used to form materials with a high electrical conductivity during a process time between 10µs - 50µs. The advantage that EMF is a non-contact forming process can be used to determine material characteristics without any influence of friction. Additionally, in contrast to other testing methods the assumption of a mean strain rate over the process time is not needed, because the evaluation is done by finite element simulations. To compute the associated flow curve array, where the strain rate is the third dimension, a method will be proposed combining an online measurement technique and iterative finite element simulations. During EMF of the tube specimen, the radial displacement of at least one significant point at the tube surface is measured online. These data are used as reference values for the iteration scheme. The iteration starts with the material data of a quasistatic tensile test. In order to minimise the deviations between online measurement and simulation result an automated data modification scheme is implemented. The kernel of this scheme consists of an optimisation algorithm and two finite element codes. The first one is used to compute the deformation process of the specimen in a conventional transient way. The second code is implemented to calculate the body force distribution by a harmonic electromagnetic analysis. These two codes are coupled in a weak staggered approach.
Subject Headings: electromagnetic Forming
finite Element Method
parameter identification
URI: http://hdl.handle.net/2003/27054
http://dx.doi.org/10.17877/DE290R-8574
Issue Date: 2004
Publisher: Institut für Umformtechnik - Technische Universität Dortmund
Is part of: 1st International Conference on High Speed Forming, March 31, April 1, 2004, Dortmund, Germany
Appears in Collections:High Speed Forming 2004

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