Title: Modelling of composite failure during vehicle crash using cohesive elements

Authors: S. Engel; C. Bögle; D. Lukaszewicz

Addresses: BMW AG, Research and Innovation Centre, Knorrstrasse 147, 80788 Munich, Germany ' BMW AG, Research and Innovation Centre, Knorrstrasse 147, 80788 Munich, Germany ' BMW AG, Research and Innovation Centre, Knorrstrasse 147, 80788 Munich, Germany

Abstract: Composite utilisation for vehicle crash applications currently relies on extensive testing since numerical simulation tends to be complex and time consuming. Simulation of inter- and intralaminar failure commonly employs highly refined meshes, while full vehicle crash models commonly use coarse shell meshes. Here, axial impact and three-point bending impact tests were conducted and simulated using a layered shell approach. Coarse meshes and cohesive elements were used with several plies grouped into individual shells to reduce the number of degrees of freedom and thus enhance the numerical efficiency. Cohesive element properties were then simultaneously calibrated against the test data using adaptive response surface methodology. After calibration simultaneous simulation of both failure modes in axial crushing and three-point-bending proved to be difficult. In particular, the peak load for axial crushing and the deformation depth for three-point-bending could not be replicated. The results demonstrate the current limitations of composite failure modelling using coarse cohesive and shell elements with respect to full vehicle simulations and future routes forward are discussed.

Keywords: vehicle crashes; crash testing; automotive composites; simulation; cohesive elements; calibration; composite failure modelling; axial impact tests; three-point bending impact tests; layered shell; response surface methodology; RSM; peak load; axial crushing; deformation depth.

DOI: 10.1504/IJAUTOC.2015.071130

International Journal of Automotive Composites, 2015 Vol.1 No.4, pp.333 - 348

Received: 26 Mar 2014
Accepted: 13 Oct 2014

Published online: 13 Aug 2015 *

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