Kinetic Grid Mechanisms

Department: Architecture
Active Dates: December 2019 - ongoing
Principal Investigator: Eike Schling (HKU) and Jonas Schikore (TUM)
Funding Body: Architectural Research Incubator, TUM
Academic Advisor: Rainer Barthel, TUM, Chair of Structural Design
Project Team: Eike Schling, Jonas Schikore, Muye Ma, Wesley She

Project Description

Transformable structures are 4-dimensional and offer to design through time, beyond the static, by adapting to environmental conditions, structural influences or user’s needs. We can distinguish between conventional rigid-body mechanisms and compliant mechanisms (Howell 2002) which utilize the elastic properties of the material to perform a change in geometry without the need for hinges. Recent developments in computational modelling (Kiendl 2011) have substantially elevated the possibilities for designing and simulating large deformations, thus paving the way for a new research branch of bending active structures (Lienhard 2014).

This project researches fundamental principles of semi-compliant mechanisms, focusing on quadrilateral grid structures with uniaxial rotational (scissor) joints built from initially straight, continuous beams. We use specific lamella profiles that restrict the elastic deformability (Schikore et al. 2019), disabling at least one of the three local bending axes. Depending on the orientation of the profiles, we can categorize three families – double-ruled (straight), geodesic and asymptotic networks (Schling et al. 2017) – each exhibiting distinct kinetic properties with limited degrees of freedom. By controlling the structure’s parameters, we can design their shape and behaviour.

Even though we approach this topic from an architects point of view, we can find fundamental similarities with the theory of differential geometry, some of which have been described as early as 1897 by the mathematician Sebastian Finsterwalder (Finsterwalder 1897), who describes the analogy of curvature lines on surfaces and physical members within elastic grids.

This typology has recently been re-discovered for architecture through the erection of a lamella gridshell following the asymptotic curves on a digital design surface (Schling et al. 2018). Current investigations on deployable grid structures called “X-Shells” (Isvoranu et al. 2019) as well as a subclass limited to geodesic grids called “G-Shells” (Soriano et al. 2019) are dealing with similar compliant transformations, investigating their design from an initially flat starting point.

Objectives

It is our goal to establish a comprehensive digital workflow to design kinetic grid mechanisms, simulate their behaviour in dependency of geometric and mechanical parameters, and analyze their structural performance in the dynamic and static state. We will use this workflow to create an analytical morphology that informs future architectural design. We will focus on one specific architectural application, the Kinetic Umbrella, to develop feasible constructive solutions, looking at their materiality, actuation and locking, as well as load-bearing capacity.

The Kinetic Umbrella

The Kinetic Umbrella is a transformable structure of 8 m span, that is currently being developed and will be the primary output of this research project.  The structure is designed from continuous GRP profiles on two levels. The umbrella performs a semi-compliant transformation from a packed bundle to a deployed umbrella. The mechanism is actuated through meridian and ring cables, which shorten the distance between joints and thus change the angles of rhombuses within the structure. Shortening the upper ring will close the umbrella, shortening the meridian cables will pull the umbrella down into its unfolded shape.

 Output

  •  Schikore, Jonas; Schling, Eike; Bauer, Anna M.; Oberbichler Thomas (2020): Kinetics and Design of Semi-Compliant Grid Mechanisms. In Olivier Baverel, Helmut Pottmann, Caitlin Mueller, Tomohiro Tachi (Eds.): Advances in Architectural Geometry 2021. (to be published)
  • The Kinetic Umbrella: Construction, exhibition and workshops in Munich, Paris and Surrey 2021

Anticipated Impact

We hope that this project will become a key stone in making kinetic grid mechanisms available for architectural applications, allowing for innovative, efficient, material saving and adaptive building structures and envelopes.

References

 Finsterwalder, S. (1897): Mechanische Beziehungen bei der Flächen-Deformation. GDZPPN00211626X. In Deutsche Mathematiker-Vereinigung (Ed.): Jahresbericht der Deutschen Mathematiker-Vereinigung, vol. 6. Göttingen: Teubner (6), pp. 43–90. Available online at https://www.digizeitschriften.de/dms/img/?PID=GDZPPN00211626X, checked on 2/13/2019.

Howell, Larry L. (2002): Compliant mechanisms. New York: John Wiley & Sons.

Isvoranu, Florin; Panetta, Julian; Chen, Tian; Bouleau, Etienne; Pauly, Mark (2019): X-Shell Pavilion. A Deployable Elastic Rod Structure. In Carlos Lázaro, K.-U. Bletzinger, Eugenio Oñate (Eds.): FORM and FORCE 2019. Barcelona: International Centre for Numerical Methods in Engineering (CIMNE), pp. 606–613.

Kiendl, Josef (2011): Isogeometric Analysis and Shape Optimal Design of Shell Structures. Dissertation. Munich.

Lienhard, Julian (2014): Bending-active structures. Form-finding strategies using elastic deformation in static and kinetic systems and the structural potentials therein. Zugl.: Stuttgart, Univ., Diss., 2014. Stuttgart: ITKE (Forschungsberichte aus dem Institut für Tragkonstruktionen und Konstruktives Entwerfen, Universität Stuttgart, 36).

Schikore, Jonas; Bauer, Anna M.; Barthel, Rainer; Bletzinger, K.-U. (2019): Large torsion on elastic lamella grid structures. In Carlos Lázaro, K.-U. Bletzinger, Eugenio Oñate (Eds.): FORM and FORCE 2019. Barcelona: International Centre for Numerical Methods in Engineering (CIMNE), pp. 788–795.

Schling, Eike; Hitrec, Denis; Barthel, Rainer (2017): Designing Grid Structures using Asymptotic Curve Networks. In Klaas de Rycke, Christoph Gengnagel, Olivier Baverel, Jane Burry, Caitlin Mueller, Minh Man Nguyen et al. (Eds.): Design Modelling Symposium Paris 2017. Humanizing Digital Reality. Singapore: Springer, pp. 125–140.

Schling, Eike; Kilian, Martin; Wang, Hui; Schikore, Jonas; Pottmann, Helmut (2018): Design and Construction of Curved Support Structures with Repetitive Parameters. In Lars Hesselgren, Karl-Gunnar Olsson, Axel Kilian, Samar Malek, Olga Sorkine-Hornung, Chris Williams (Eds.): Advances in Architectural Geometry 2018. 1. Auflage. Wien: Klein Publishing, pp. 140–165.

Schling, E.: Repetitive Structures – Design and Construction of Curved Support Structures with Repetitive Parameters. Dissertation 2018. Chair of Structural Design, Technical University of Munich.

DOI: 10.14459/2018md1449869

https://mediatum.ub.tum.de/doc/1449869/1449869.pdf

 

Soriano, Enrique; Sastre Ramon; Boixader, Dionis (2019): G-shells. Flat collapsible geodesic mechanisms for gridshells. In Carlos Lázaro, K.-U. Bletzinger, Eugenio Oñate (Eds.): FORM and FORCE 2019. Barcelona: International Centre for Numerical Methods in Engineering (CIMNE), pp. 1894–1901.

 

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UNIVERSITY OF HONG KONG
FACULTY OF ARCHITECTURE