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SUMMARY:Novel application-driven deployable SAR system adopting high strai
 n composites  - Annalisa Tresoldi
DTSTART:20241213T150000Z
DTEND:20241213T160000Z
UID:TALK225478@talks.cam.ac.uk
CONTACT:Callum White
DESCRIPTION:Synthetic Aperture Radar (SAR) technology capabilities\, such 
 as high-resolution imaging\, continuous monitoring\, tracking\, etc.\, can
  be further exploited by employing CubeSats. However\, the availability of
  onboard resources severely challenges the installation of large space ins
 truments on CubeSats. This work investigates the feasibility of a SAR Depl
 oyable Rolled-up Composite Antenna (DERCA-SAR) concept tailored for a 12U 
 CubeSat low-power remote sensing application. A SAR reflectarray system is
  considered to be implemented on a high strain composite structure with a 
 shallow “tape-measure” inspired shape. To provide stiffness in the dep
 loyed state\, the cross-sectional curvature of the shell is rigidly mainta
 ined at the root during stowage and fully recovered along the shell's leng
 th after deployment when the elastic energy stored in the coiled configura
 tion is released. A suitable range of the shell's cross-sectional curvatur
 e and thickness is outlined from an initial trade-off study conducted to a
 ssess the stiffness in the deployed state through natural frequency analys
 es. The flexibility of the DERCA-SAR shell is exploited through a coilable
  stowage process. The required coiling torque\, the elastic strain energy 
 stored and the ploy region are the main aspects of the coiling process tha
 t are addressed through experimental work and numerical and analytical mod
 els. An improvement is achieved in the natural and shortened transverse cu
 rvature field predictions of the ploy region by initially applying non-uni
 form boundary conditions and eventually employing a high-order polynomial 
 function to describe the variation of the transverse curvature in the ploy
  region. Concerning the deployment process\, experimental tests and finite
  element models are used to develop mathematical models based on Lagrangia
 n approaches that describe the deployment dynamics of this structure in tw
 o deployment phases and predict the deployment time and velocity that may 
 impact the antenna performance. The first blossoming phase is analytically
  well predicted\, capturing the coil's translation during blossoming using
  a convective reference frame. The second and more chaotic phase\, which i
 s modelled using a Hencky-type system with non-linear stiffness\, shows to
 tal deployment times and velocities that are coherent with testing\, revea
 ling that minor changes in the \nmechanical properties of the laminate wou
 ld noticeably affect the deployment dynamics. \n
LOCATION:CivEng Seminar Room (1-33) (Civil Engineering Building)
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