Structural morphing induced by functionalising buckling: Fid-Bau Portal

Structural morphing induced by functionalising buckling

Khezri, Mani / Hu, Yang / Luo, Quantian / Bambach, Mike R. / Tong, Liyong / Rasmussen, Kim J.R.

Abstract The paper presents an overview of a research project at the University of Sydney aimed at developing a general framework for the analysis and design of functional components of buildings and structures, where such components achieve large shape changes (morphing) via buckling. The shape changes are optimised, e.g. to reduce energy consumption by minimising solar radiation loads or maximising natural air ventilation. The underlying driver for the project is to develop innovative building technology solutions to reduce the energy consumption of the next generation of low-, medium- and high-rise buildings. The paper first summarises recent work on plate elements supported along three edges, in which temporary intermediate restraints are used to load the plate into the post-buckling range and subsequently released to generate an abrupt shape change in response to an external signal triggered by shading or ventilation demand. This investigation is backed by an analysis of the placement of intermediate restraints to optimise the plate deflection by maximising the pre-buckling compression of the plate. Next, a study is presented on optimising the topology of plates to maximise their shading or ventilation capacities under applied compression or bending. Considering both buckling and nonlinear post-buckling, the analytical framework optimises the spatial distribution of plate thickness. Experiments on optimised plates are reported as well, in which shape memory alloy (SMA) and piezoelectric (PZT) actuators are used to induce compression and buckling. Subsequently, morphing induced by flexural–torsional buckling is investigated where simple 3-member frame geometries are devised to achieve large lateral buckling displacements and twist rotations under low-power external excitation. Lastly, an application of functionalised buckling for shading of buildings is illustrated which employs a bi-stable mechanism powered by shape memory alloy actuation.

Highlights • Provides an overview of recent research on functionalising plate and frame buckling. • Describes the basic idea of using temporary restraints to mobilise instantaneous shape change. • Describes the basic idea of twisting supports to produce large buckling deflections of simple frames. • Summarises a novel formulation for optimising plate topology for optimal buckling deformation. • Presents an example of using snap-buckling to design shading modules.