EPJ Web Conf.
Volume 183, 2018DYMAT 2018 - 12th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
|Number of page(s)||6|
|Section||Modelling and Numerical Simulation|
|Published online||07 September 2018|
Experimental analysis and modelling of the strain-rate sensitivity of sheet niobium
Politecnico di Torino, Department of Mechanical and Aerospace Engineering,
Corso Duca degli Abruzzi 24,
* Corresponding author : firstname.lastname@example.org
Published online: 7 September 2018
The niobium is currently used for the construction of the superconducting radio frequency (RF) Crab Cavity for the particle accelerator LHC at CERN in Geneva. An alternative technique to traditional forming methods is the electrohydraulic forming (EHF), in which ultrahigh-speed deformation of blank sheets is performed by using shockwaves electrically induced in water. A big effort is made for the analysis of the forming processes by FEM simulations, which require the definition of an appropriate flow stress material model. With this aim, in the present work, a testing campaign was performed in tension on sheet specimens with a rectangular cross-section at different strain-rates, up to 103 s-1. The obtained results showed the material is strongly sensitive to strain-rate, as expected for a pure BCC metal. The data, were processed via a reverse engineering procedure, based on finite element simulations of the experimental tests. This methodology allowed the identification of a tabular flow stress model (MAT_224 implemented in LSDYNA) for the prediction of the material behaviour as a function of the plastic strain, strain-rate and temperature.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.