Introduction

Deployable structures are a novel and unique type of engineering structure, which can be packaged for transportation and expanded at the time of operation. They retain the functionality of conventional structures, but are also able to undergo large geometric transformations. This subject encompasses both mechanical and structural engineering.

The development of deployable structures is a critical technology for satellite communications and other space systems. There are three commonly used types of deployable spacecraft structures: masts, i.e. slender, one-dimensional elements; solar arrays, i.e. two-dimensional, flat structures covered on one side with photovoltaic cells; and reflectors for telecommunications and telescopes. Typical dimensions of deployable structures currently in use are: masts up to 50 m long, solar arrays with surface area of 500 m2, and reflectors with diameter up to 10 m. On-going projects, such as the Euro-African Satellite Telecommunications services proposed by Matra Marconi UK Ltd, aimed at offering high quality fixed and mobile telephony services over the whole of Europe, the Middle East and Africa; the In-Step Inflatable Antenna proposed by NASA, and the International Space Station Alpha jointly developed by NASA and the European Space Agency, Japan and Russia, all involve large structures.
Obviously, such structures cannot be delivered into space in their service configuration because launching vehicles are, and in the foreseeable future will continue to be, limited in size. This presents a considerable challenge and offers exciting opportunities for imaginative concepts and ideas. But new concepts are only the first stage in the complex development of new deployable spacecraft structures. These structures have to be expanded automatically in the harsh space environment, after several months pre-flight stowage; during launch they undergo high accelerations and vibration levels. Failures are expensive and difficult to rectify, but they do happen. Most recent examples include important deployable components on both the Galileo Space Probe and the Hubble Space Telescope. This indicates that our present knowledge of large deployable structures is inadequate and there is a need for in-depth research into structural configurations, analytical simulations of in-orbit behaviour, and ground testing to ensure the success of future space missions.

My interests in this subject started in 1991 when I arrived at Cambridge to study for a Ph. D degree. My work has focused on two type of structures: deployable frames and tension structures. Having realised that previous research on deployable space frames had resulted in highly complex solutions requiring a vast number of spring-loaded joints or motorised hinges, I decided to develop new concepts with simple joints, inexpensive manufacturing, and robust performance. For instance, all of my deployable frame concepts use only pivoted joints and have a single internal degree of freedom despite being geometrically over-constrained. These solutions have been found by systematically using symmetry and making careful simplifying assumptions.

Please click different projects to see my work on different structural forms.

• Structural Mechanisms
• Deployable Space Frames
• Retractable Structures
• Design Optimisation and Shape Adjustment
• Cable Net Structures
• Membrane Structures

Key Words

pantographs | dynamic & | kinematic simulation | finite element method | force method | geometry | linkages | mechanisms | prestress | retractable roofs | sensitivities | single degree of freedom system | topology

This page is created by Zhong You, who is a university lecturer in the Department of Engineering Science of Oxford University. This is a link to his current address. You may e-mail zhong.you@eng.ox.ac.uk for further infomation.

Zhong was an EPSRC advanced fellow based at Cambridge University before moving to Oxford.