CHEN Yan's Home Page

Deployable Structure

Introduction

Deployable structures are structures whose shape can undergo large geometric transformation to meet the practical requirement. They exist in people’s daily life, e.g. balloons, umbrellas and foldable chairs, etc. In spite of having different sizes and functions, there is a common feature among them: they all retain the functionality of conventional structures but are capable of undergoing large geometric transformation.

Deployable structure in our daily life

In the last four decades, research in the design of structural mechanisms has primarily been driven by aerospace applications where large structures have to be packaged into small volume for launch, and expanded when they reach orbits. The three most commonly used deployable spacecraft structures are masts, solar arrays and reflectors. Deployable structures are also used in earth-bound applications as emergency or temporary shelters, portable exhibition stands and retractable roofs of swimming pools or stadiums. In recent years, there is a significant development in medical engineering in the use of deployable structures, such as expandable stents used in the gastrointestinal tract or blood vessel to treat the cancer, permanent expandable implants in breast reconstructive surgery, and balloons inserted into stomach as anti-obesity device.

Deployable structure in aerospace engineering

Deployable structure in civil and medical engineering

In most design, planar mechanisms are selected as building elements for construction of large deployable structures of 3D geometry. 3D mechanisms are rarely used. The reason is probably due to the highly non-linear nature of compatibility conditions and mathematical difficulty in finding solutions which ensure that the mobility of each building element is retained. The first attempt of utilising 3D mechanism was my PhD research on the theory of deployable structures based on the Bennett and Bricard linkages, which are two most well-known 3D mechanisms. A family of novel structures have been developed, all of which have a single degree of mobility and are geometrically over-constrained.

Deployable structure based on Bennett linkage

Deployable structure based on Bricard linkage

More work is carrying out on the design and analysis of deployable structures based 3D mechanisms for various engineering appilcations.

Other links:
Deployable structures can also be found in many intereting toys. The most famous one is: Hoberman sphere.
Deployable structures can also be found in natural as folding leaves.

Back to Chen Yan's homepage