INVERSE COMPUTATIONAL DETERMINATION OF JOHNSON-COOK PARAMETERS USING THE SHPB TEST APPARATUS

Authors

  • Anja Mauko University of Maribor, Faculty of Mechanical Engineering, Smetanova ul. 17, 2000 Maribor, Slovenia
  • Branko Nečemer University of Maribor, Faculty of Mechanical Engineering, Smetanova ul. 17, 2000 Maribor, Slovenia
  • Zoran Ren University of Maribor, Faculty of Mechanical Engineering, Smetanova ul. 17, 2000 Maribor, Slovenia

DOI:

https://doi.org/10.14311/APP.2019.25.0064

Keywords:

SHPB test apparatus, Johnson-Cook constitutive model, inverse determination, NelderMead optimization, computer simulations

Abstract

The paper describes determination of the material parameters of the Johnson-Cook constitutive model of steel S235 JR sample material by applying the inverse computational methodology using the digital twin model of the SHPB. A quasi-static tensile testing of bulk material was conducted first to determine the base material parameters. This was followed by dynamic impact testing at two different strain rates using the SHPB. A digital twin computational model was built next in the LS-Dyna explicit finite element system to carry out the necessary computer simulations of the SHPB test. The inverse determination of strain hardening material parameter of Johnson-Cook model was done by using the Nelder-Mead simplex optimisation by comparing the measured and computed stress to time signals on incident and transmission bars. The obtained Johnson-Cook material parameters much better describe the sample material behaviour at very high strain-rates in computational simulations, if compared to the parameters derived by the classic, one-dimensional wave propagation Hopkinson procedure.

Downloads

Published

2019-12-06

Issue

Vol. 25 (2019): 17th YOUTH SYMPOSIUM ON EXPERIMENTAL SOLID MECHANICS

Section

Articles

License

Copyright notice

Authors who publish with this journal agree to the following terms:

1. Authors retain copyright and grant the journal the right of the first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
2. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., to post it to an institutional repository or to publish it in a book), with an acknowledgement of its initial publication in this journal.
3. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges as well as earlier and greater citation of the published work (See The Effect of Open Access).