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FIMCAR V: Off-set Test Procedure: Review and metric Development

Lazaro, Ignacio; Vie, Nicolas; Thomson, Robert; Schwedhelm, Holger

The off-set test is the most common test procedure in vehicle crash testing. These procedures are currently used in the European frontal directive (96/79/EC) and in consumer tests like Euro NCAP, IIHS, etc. In both compulsory and consumer testing cases, the ODB test consists of an impact into a honeycomb barrier (EEVC barrier) with a 40% overlap. The current ODB procedures only assess the self-protection of the tested vehicle. There are no methodologies investigating the partner-protection (e.g. structural interaction or frontal force levels) using these test configurations. Another off-set test procedure – the Progressive Deformable Barrier (PDB), a 50% off-set test – has been investigated for structural interaction and frontal force level assessment. The PDB is considered as the most promising off-set test procedure to assess partner-protection issues. In the PDB test, the deformation of the honeycomb barrier can be measured after the test. The PDB honeycomb is stiffer than the EEVC barrier and becomes progressively stiffer with increased deformation. The barrier 3D deformation profile is used to analyse the structural interaction and force levels of the tested vehicle. The PDB assessment procedure shall use the barrier deformation as an input. The specific objective of the deliverable is to define the fundamental concepts for developing assessment criteria and associated performance limits for the off-set test procedure. In an initial phase, existing test procedures have been investigated and an initial assessment methodology has been developed. This includes the review from past compatibility research projects and review of current test protocols. The robustness of the assessment criteria is investigated and potential for misuse in vehicle design is identified. Full scale tests and simulation studies were performed to investigate topics like robustness, repeatability and reproducibility of the test and the assessment criteria. Existing Euro NCAP tests performed in recent years were used to support this investigation. Based on the results of the tests performed, different proposals for criteria and limits have been investigated. Although the PDB is a promising procedure to evaluate compatibility issues such load spreading, at this stage of the project the criterion was not possible to be fully developed. For this reason the ODB is proposed as off-set test procedure, the ODB procedure will maintain the current self-protection requirements. However, PDB might still be an option for the future when validated compatibility metrics can be proposed. Therefore, the FIMCAR consortium agreed to further develop PDB criteria.
Published in: FIMCAR - Frontal Impact and Compatibility Assessment Research. - ISBN 978-3-7983-2614-9, Universitätsverlag der TU Berlin