Faralli, Anna Chiara;
(2019)
Large deformation of T-stub connection in bolted steel joints.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Existing regulations on bolted steel joints (Eurocodes) require that the rotational capacity of joints be certified by experiments during the design phase. The rotational capacity depends on the deformation capacity of its components in bending, which are represented by an equivalent T-stub. Understanding how large deformation develops in T-stubs is, therefore, needed to characterise the joint performance. However, the Eurocodes only provide guidance on how to determine the moment resistance of a joint and no information were provided on how to determine their rotational capacity. This thesis investigates the mechanical performance of bolted T-stub connections undergoing large displacements and will form part of an eventual extension of the existing regulations. An initial assessment of Eurocode 3 – the primary focus will be on the deformation mode experienced by a T-stub – is first performed. Maps are generated onto which deformation modes are plotted in a two-dimensional geometric and material parameter space. In general, the deformation mode predicted by Eurocode 3 is, unsurprisingly, conservative, i.e. a T-stub is predicted to deform in mode 2 (or 3) when it actually deforms in mode 1 (or 2). This misprediction will be traced to the omission of geometric non-linearity in Eurocode 3, which affects the ductility of deformation of a T-stub and, consequently, the mode of deformation that it develops. Experiments and a detailed parametric study by finite-element simulations were performed to elucidate the effects of geometric non-linearity on the global displacement of T-stubs. Bolt deformation (and failure) in shear and catenary actions in the flange were found to be the two principal mechanisms through which a T-stub develops large displacement during tension; and, these effects were incorporated into an improved mechanical model to account for these sources of, hitherto neglected, geometric non-linearity. Last, a preliminary criterion to assess the significance of catenary effects in the tensile response of a T-stub is developed based on the plastic energy dissipated by axial force in its flange. This criterion is as an initial attempt to extend the Eurocodes to include the effects of geometric non-linearity that develop in the components of a bolted steel structural joint.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Large deformation of T-stub connection in bolted steel joints |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2019. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10080174 |
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