PMQ Exhibition – Kinetic Grid Structures

14 September – 5 October 2021
HKU Architecture Gallery
S503 – PMQ – 35 Aberdeen St. – Central

Welcome to the website of Kinetic Grid Structures, the interactive exhibition at PMQ, Hong Kong. The exhibition introduces research from the University of Hong Kong (HKU) and the Technical University of Munich (TUM) through interactive models and movies, and shows a full-scale documentation of the Kinetic Umbrella.

Introduction
Advances in architectural geometry have revealed a new kind of spatial mechanism that can be constructed from straight elastic lamellas connected through scissor joints. These kinetic lamella grids can be easily manufactured and offer a controlled movement from a flat into a doubly curved shape. This has the potential to inform the design of transformable structures at all scales from foldable roofs and adaptive building facades to medical stents for heart surgery. The Kinetic Umbrella, our first large-scale architectural application, has just been completed in Munich.

Modeling Process
We investigate various design possibilities and actuation techniques for kinetic grids. All models are built from initially straight glass fibre rods and connected with durable 3D printed joints. This allowed us to physically test various combinations and network topologies.

film by Alyssa Williams

Digital Design
The models are design digitally. They are based on smooth surfaces of negative curvature, mainly minimal surfaces. We generate so-called asymptotic curves on these shapes, which follow the path of zero normal curvature. It is these paths, that enable the specific configuration of slender straight lamellas, which create high structural resilience, and offer controlled elastic transformations.

Asymptotic Curves on Minimal surface
A: A physical soap film bounded by steel wires creates a minimal surface. B: Such a surface has particular properties. The two principal curvature directions k1 and k2 (red), are bisected by the asymptotic directions a1 and a2 (orange) C: To better illustrate this relationship of the principal and asymptotic directions, we created a graph, showing the maximal, minimal and zero values.

Kinetic Behaviour
The kinetic properties of the structures can be simulated. This allows us to measure the curvatures around all three axes of each fiberglass lamella and deduce the elastic energy that results from the bending and torsion. These simulations not only enable a precise understanding of the kinetic behaviour, but also allow a prediction of the natural equilibrium states of minimal energy.
In our further exhibition, we will show the distribution of torsion and bending for 5 transformation stages of each model. These diagrams illustrate, where the curvature is highest, and will cause elastic strain. Next to each diagram, we give the value of total curvature square, an indicator of the overall deformation. The grids tend to seek the position of least energy, indicated by this number.

film by Alyssa Williams

Six-Point Sail

Shape: Single Schwarz D Minimal Surface
Singularities: 1
Number of Lamellas: 24
Total Lamella Length: 716 cm
Number of different Lamellas: 4
Number of Joints: 98

Tricylinder

Shape: Closed Minimal Surface
Singularities: 2
Number of Lamellas: 24
Total Lamella Length: 921 cm
Number of different Lamellas: 2
Number of Joints: 82

Quadcylinder

Shape: Periodic Schwarz D Minimal Surface
Singularities: 4
Number of Lamellas: 48
Total Lamella Length: 2503 cm
Number of different Lamellas: 2
Number of Joints: 216

Regular Grid, actuated

Shape: Flat to Pseudosphere
Singularities: 0
Number of Lamellas: 18
Total Lamella Length: 1080 cm
Number of different Lamellas: 1
Number of Joints: 81

Support and Actuation:
Central lamella joints constrained to 90°
Top Joint Supported in X and Z
Side Joints Supported in Y and Z
Actuated by pulling side and top together

Hypar Grid, actuated

Shape: Flat to Hypar to Enneper
Singularities: 0
Number of Lamellas: 16
Total Lamella Length: 912 cm
Number of different Lamellas: 1
Number of Joints: 64

Support and Actuation:
Central joints constrained to 90°
Central joints supported in X, Y, Z
Actuated by changing the angle of diagonal
quads.

Regular Cylindrical Grid

Shape: Cylinder to Pseudosphere to Flat
Singularities: 0
Number of Lamellas: 24
Total Lamella Length: 1584 cm
Number of different Lamellas: 1
Number of Joints: 108

Timber Umbrella, Model 1:10

Shape: Funnel
Singularities: 0
Number of Lamellas: 24
Total Lamella Length: 2040 cm
Number of different Lamellas: 1
Number of Joints: 120

Kinetic Umbrella, Model 1:10

Shape: Funnel to cylinder
Singularities: 0
Number of Lamellas: 32
Total Lamella Length: 1056 cm
Number of different Lamellas: 1
Number of Joints: 192

Support and Actuation:
All bottom Joints are fixed in X,Y,Z
Actuated by tightening the ring cable

The Kinetic Umbrella
The Kinetic Umbrella is an elastically transformable lattice structure that was completed in August at the Kreativquatier in Munich. The research project investigates geometrical, mechanical and constructive solutions for kinetic structures, which are manufactured from exclusively straight lamellas. In the design, the joint and support conditions as well as the bending stiffness of the bars are specifically controlled in order to achieve a complex, spatial transformation of while maintaining a high load-bearing capacity.

film by Alyssa Williams

The Kinetic Umbrella consists of 32 slender FRP (Fibre Reinforced Plastic) lamellas (8×80 mm), which are assembled diagonally in two layers. The tall FRP profiles create a high resistance to external loads through their strong axis, and – at the same time – smooth elastic bending and twisting around their week axis. They are connected through aluminum joints with plain bearings, that enable a smooth mechanism. The Kinetic Umbrella can change its shape from a 6m high cylinder into a cantilevered funnel with 8m span. The grid is mounted on a ring-shaped steel structure that facilitates the outward tilt of the structure. By slowly releasing and pulling a ring cable the grid can be easily opened and closed. Three additional rings at the outer, mid and low perimeter secure the final unfolded shape. The diagonal grid is covered with parallel textiles, that follow the changing geometry and offer partial sun protection.

Exhibition Curator:
Eike Schling

Research Team HKU:
Jan Yip Choy, Ka Mak Fan, Hao Feng Chuah, Hing Fung Li, Zongshuai Wan, Jacky Chu, Muye Ma

Photographer HKU: Jason Ji Xiang
Movies HKU: Alyssa Williams
Photographer TUM: Jonas and Anna Schikore

Academic Partner, TUM:
Jonas Schikore M. Sc. (Project Lead: Kinetic Umbrella)
Technical University of Munich,
Faculty of Architecture
Pierluigi D’Acunto, Professor for Structural Design

Kinetic Umbrella Project Team:

Frauke Wilken, Tao Sun, Clemens Lindner, Frederic Chovghi, Fabian Matella, Maria Rau, Sarah Sendzek, Sebastian Hoyer, Merlin Bieling, Sanziana Maximeasa, Sebastian Dietrich

Industry Partners:

BRANDL Metal Manufactorer
Erhard Brandl GmbH & Co. KG
Metal Manufacturer, Eitensheim

FACTUREE Aluminium Joints
cwmk GmbH
Oudenarder Str. 16
13347 Berlin

GEPOTEX Ribbons and Ropes
Gerhard Popp
Ziegelhüttenweg 3
D-91448 Emskirchen

Funding Bodies:

Dr. Marschall Stiftung
Werner Konrad Marschall und Dr.-Ing. Horst Karl Marschall Stuftung
Arcisstr. 21
80333 Munich

Sto Foundation
DSZ – Deutsches Stiftungszentrum GmbH
Barkhovenallee 1
45239 Essen, Germany

Please let us know how we can improve this page, and the exhibition!

About eikeschling

Dr.-Ing. | Architect BYAK Assistant Professor in Architectural Structures The University of Hong Kong

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