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Liesbeth Arnouts

Liesbeth Arnouts

Ir. arch. Liesbeth Arnouts is a PhD researcher at the Structural and Material Computational mechanics group of the Université libre de Bruxelles (ULB) and the Architectural Engineering Lab of the Vrije Universiteit Brussel (VUB). The research project, under the supervision of prof. dr. ir. Péter Z. Berke, prof. dr. ir. arch. Niels De Temmerman and prof. dr. ir. Thierry J. Massart, targets the development of a robust computational design methodology for bistable scissor structures using advanced modelling tools.

PhD research

Bistable Scissor Structures - Computational Design and Modelling

Date2017 - ...
SupervisorsPėter Z. Berke, Niels De Temmerman and Thierry J. Massart
FundsFonds de la Recherche Scientifique - FNRS

In many engineering applications (emergency shelters, exhibition and recreational structures...), structures need to be easily moveable, or assembled at high speed on unprepared sites. For this purpose, preassembled deployable scissor structures, which consist of beam elements connected by hinges, are highly effective: besides being transportable, they have the advantage of speed and ease of erection and dismantling, while offering a huge volume expansion. Intended geometric incompatibilities between the members can be introduced as a design strategy, to instantaneously achieve a structural stability that can be sufficient for small loads after deployment. In so-called bistable scissor structures, these incompatibilities result in compression and bending of some specific members that are under compression with a controlled snap-through behaviour. Despite the advantages bistable scissor structures have to offer, few have successfully been realized because of the complexity they add in the design process.

The main goal of this research is to obtain better performing bistable scissor structures by identifying and manipulating their most critical parameters. The expected outcomes are structural designs in which the material is efficiently used and in which deployment remains possible with sufficient safety. An additional use of the findings issued from the planned numerical modelling is to provide engineers with general guidelines on how to design such structures.

Master’s thesis

Computational Investigation of the Structural Response of Bistable Scissor Structures

Date2016 - 2017
SupervisorsThierry J. Massart and Niels De Temmerman

In many applications structures need to be easily moveable, or assembled at high speed on unprepared sites. For this purpose, preassembled deployable structures, which consist of beam elements connected by hinges, are highly effective. Intended geometric incompatibilities between the members are introduced for instantaneous structural stability after deployment. In such bistable scissor structures, these incompatibilities result in the bending of some specific members that are under compression with a controlled snap-through behaviour. The main goal of the thesis is to qualitatively and quantitatively discuss the behaviour of bistable scissor structures during deployment. To do this, a 3D nonlinear structural model is proposed to simulate the deployment, including explicitely geometrical imperfections in a stochastic approach. The originality of this work is (i) the implementation of gravity, (ii) the geometrical imperfections and (iii) the extension of the numerical model to complex deployable structures. Bounds on geometrical tolerances on several uncertain parameters (length of the beams, eccentricity of the pivot points, hinge misalignment and finite hinge stiffness) are proposed based on non-linear finite element simulations on a single module transformation. The computational tool is then applied to structures consisting of multiple modules and the influence of geometrical imperfections is characterized.

Awards

BrEA award

Date2017
Granted byBrEA

Award for the best master thesis in the field of Architectural Engineering

Victor Horta Award

Date2017
Granted byArt&Build

Award for the most valuable student in Architectural Engineering

Prix Strabag - Innovation en construction

Date2017
Granted byStrabag

Prize awarded to the graduate whose Master Thesis shows the best added value to civil engineering at large