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Introduction
Dr Mark Schenk
Lecturer in Aerospace Engineering
started at Bristol in October 2014
(previously Surrey Space Centre, University of Cambridge)
Research interests
• folding structures (i.e. engineering origami)
• deployable space structures
Folded Structures
Mechanics of Folding/Folded Structures
• folding kinematics + structural mechanics
• applications: morphing, metamaterials, deployables
• exploring embedded actuation
twist
saddle
Deployable Space Structures
Deployable Space Structures
Deployable structures are folded up during launch, and
unfurled to their full dimensions once in space.
Examples: solar arrays, antennas, reflectors, instrument
masts, gossamer sails, etc.
Deployable structures have unique and often contradictory
requirements, providing very interesting structural
challenges.
Deployable Space Structures
Mechanics of Deployable Space Structures
1. compact stowage of large structures
e.g. folding methods, large displacements and deformations
2. reliable and predictable deployment
e.g. strain energy control, deployment forces
3. structural performance after deployment
e.g. long slender booms, tensioned membranes, thin shells
Deployable Space Structures
InflateSail: technology demonstration mission
3U CubeSat (10x10x30 cm)
• 10 m2 gossamer sail
• 1 m long inflatable mast
Objective: demonstrate
feasibility of drag augmentation
to de-orbit satellites from LEO
EU FP7 funding / QB50 launch
PI: Prof. V. Lappas, University of Surrey
Deployable Space Structures
InflateSail: Inflatable Deployable Mast (video)
• cylindrical mast (D = 90 mm)
• rapid inflation (< 10 s)
Deployable Space Structures
Geometry and Deployment Kinematics
Deployable Space Structures
Post-Deployment Mechanics
• membrane material is a 45 µm
Aluminium-Mylar laminate
• Al: stiffness
Mylar: toughness
• strain-rigidisation: long-term
structural performance by
removing creases through
local plastic deformation
Al
Mylar
Al
Deployable Space Structures
Post-Deployment Mechanics
• investigate efficacy :
stiffness vs inflation pressure
• first natural frequency as
indication of stiffness: 𝐸𝐼 ∝ 𝜔𝑛2
• modelling currently intractable,
incomplete understanding
of creased materials
Deployable Space Structures
Deployment Mechanics
• test anomalies:
rapid pressure drops
shortly after inflation
• visco-elastic effects
in laminate and adhesives
• currently quantifying
and modelling these effects
(AIAA 2016)
Deployable Space Structures
Deployable Gossamer Sail
Deployable Space Structures
Deployable CFRP booms
• four deployable booms unfurl
and tension the sail membrane
• thin-ply, bi-stable CFRP booms
with variable ply angle (RolaTube)
• deployment
mechanisms
University of Bristol CubeSat
• setting up University of Bristol CubeSat : UoB-Sat-1
• educational project, but also a technology demonstration
platform to showcase research
• call for payload proposals, deadline: 16th September 2015
More information: http://www.uobsat.uk/
Questions
Questions?
