This report presents some notes on the use of pinball-based contact-impact models with friction by the method of Lagrange Multipliers (LM) in EUROPLEXUS [1] (also abbreviated as EPX).
Recently, EPX is being used to simulate vehicle crash against obstacles such as road barriers for safety and security studies. These studies involve complex contact-impact scenarios, which in EPX are typically modelled by the method of Lagrange Multipliers (LM), although other methods (e.g. penalty-based) are also available in the code. In some test cases, the effect of friction may be important and it must be included in the numerical simulations.
Recent simulations concerning (elastic) impact tests with friction using the LM-based version of the pinball contact model have revealed some malfunctionings, which may be attributed to the friction model. Therefore, it has been proposed to completely review the formulation and implementation of the friction algorithm in the LM-based pinball contact model. The model used a single-tangent formulation that could lead to problems. It has now been replaced by the same friction model used by the sliding surface model (GLIS), which uses a more robust two-tangent formulation.
Despite this improvement, and the correction of other minor issues, the LM version of the PINB contact model remains somewhat fragile in cases with friction, and the penalty-based version should preferably be used in industrial applications.
CASADEI Folco;
MARKOVIC Damijan;
VALSAMOS Georgios;
LARCHER Martin;
Casadei, F., Markovic, D., Valsamos, G. and Larcher, M., Correction of friction implementation in the LM-based PINB contact model of EUROPLEXUS, Publications Office of the European Union, Luxembourg, 2023, doi:10.2760/180734, JRC134224.
2023-08-09
Publications Office of the European Union
JRC134224
978-92-68-05668-4 (online),
1831-9424 (online),
EUR 31597 EN,
OP KJ-NA-31-597-EN-N (online),
https://publications.jrc.ec.europa.eu/repository/handle/JRC134224,
10.2760/180734 (online),
