Crash elements

Compressive strength and crushing characteristics of thin-walled profiles

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The aim of this project is to develop thin-walled profiles (crash elements) which can be used to evaluate and assess the crash potential of advanced high-strength steels (AHSS) with a minimum influence of the geometry. In the case of axially crushed thin-walled profiles numerical analyses and crash tests show that preconditions for the evaluation and assessment are a regular local folding mode. Consequently, a mode change from local folding to global buckling of the profile (Eulermode) has to be avoided. Furthermore, a minimum bending radius is required in order to limit the initial deformations due to the forming process. In order to satisfy these conditions, the cross-section geometry needs to be designed in respect to the material, i. e. the steel grade. Furthermore, the influence of spot welds on both, the folding mode and the crack initiation, is investigated on the basis of numerical stress analyses and specially developed test specimens.

The strategic aim of this project is to classify high-strength steel grades suitable for crash-relevant thin-walled structures in the automotive industry. Therefore, the Visual Assessment and Categorisation Scheme (VACS) was developed [1]. The VACS consists of four parameters α, β, γ and δ. It allows to access folding-irregularities and to validate numerical analyses with axial crash tests of thin-walled top-hat sections.


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The symbiosis of the high level of material sciences on the part of the voestalpine steel AG and the expertise in structural mechanics on the part of the Institut of Structural Lightweight Design turned out to be a good basis in order to fulfil the project requirements.

[1]        B. Müller, M. Schagerl, K.-U. Schröder: A systematic approach to design crash elements and to validate FE-analyses by combining computational methods with analytical considerations. Proceedings of the 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012), 24 , 1{10}