Dynamic beam-end tests: investigation using split Hopkinson bar

0563182 - ÚTAM 2024 RIV SE eng J - Článek v odborném periodiku
Leicht, L. - Fíla, Tomáš - Máca, P. - Curbach, M.
Dynamic beam-end tests: investigation using split Hopkinson bar.
International Journal of Impact Engineering. Roč. 172, February (2023), č. článku 104417. ISSN 0734-743X. E-ISSN 1879-3509
Institucionální podpora: RVO:68378297
Klíčová slova: concrete * bond stress-slip relation * split Hopkinson bar * dynamic pull-out * beam-end test * digital image correlation * LS-DYNA
Obor OECD: Materials engineering
Impakt faktor: 5.1, rok: 2022
Způsob publikování: Omezený přístup
https://doi.org/10.1016/j.ijimpeng.2022.104417

Bond between concrete and steel reinforcement is a highly investigated topic under both quasi-static and dynamic loading conditions. Strain rate sensitivity and dynamic increase factor are the key aspects affecting the resulting response of the structure and represent crucial parameters for modelling of the impact related events. Measuring the bond properties under dynamic conditions, however, is a complex task requiring advanced experimental techniques and methodology. In this paper, the bond stress-slip relation during dynamic pull-out was measured using an innovative technique based on tensile Hopkinson bar and a near-to-full-scale beam-end specimen representing an end-part of a reinforced concrete beam. A tensile split Hopkinson bar was used to generate a tensile stress wave with a long duration that pulls a reinforcement bar with a short bond length out of the concrete block. As a very complex wave propagation behaviour was observed during the impact, the forward and backward propagating waves have to be separated and subsequently used to properly calculate the bond stress-slip relation. Two redundant methods utilizing strain gauge signals and digital image correlation for separation of the longitudinal stress waves were employed to solve the problem. The proof-of-concept and applicability of the method which is the main focus of the contribution was demonstrated with a numerical simulation performed in LS-DYNA. An exemplary evaluation of the results of the real tests performed at medium impact velocity with full pull-out of the rebar was performed. The presented method is considered suitable for evaluation of the dynamic bond stress-slip relation and produced high quality results during initial impact phase and reasonable quality results up to the full pull-out.
Trvalý link: https://hdl.handle.net/11104/0335216