The Stability of Thermo-Elastically Controlled Structures

Telecom, science and Earth observations missions typically demand thermo-elastically stable platforms to varying degrees of demand dictated by mission needs. Certain on-board payloads are required to acquire data to high levels of stable pointing accuracy that varies depending upon the nature of the mission
  • Number of scholarships One
  • Value Home/EU tuition fees and stipend
  • Opens 27 March 2017
  • Deadline 30 April 2017
  • Help with Tuition fees, Living costs
  • Duration 36 months

Eligibility

Applications should hold,  or expect to achieve a first class honours in an Engineering of Physical Sciences degree.

Open to EU/Home applicants only.

Project Details

Telecom, science and Earth observations missions typically demand thermo-elastically stable platforms to varying degrees of demand dictated by mission needs. Certain on-board payloads are required to acquire data to high levels of stable pointing accuracy that varies depending upon the nature of the mission. Mission pointing needs vary from several arc-seconds to sub-arc second angular shift of the pointing vectors, dependent upon the underlying mission and science requirements. One major source of pointing error is that arising from structural thermo-elastic distortion which, in turn, arises from either pseudo-static or time varying thermal shifts, or thermal gradients induced in the structure as a result of the variation in illumination by the Sun. Differential temperatures, along with differential material expansion characteristics, are the governing parameters inducing thermal strains or changes in shape of the core platform structure. Historically, during design, such de-point effects are budgeted for analytically via a multi-disciplinary approach involving:
1. Thermal control /analysis specialists able to predict structural thermal distributions both of a static and transient nature. The thermal mathematical models (TMMs) are subject to correlation and validation relatively late in the spacecraft development life cycle via thermal balance tests conducted in specialist vacuum chamber facilities.
2. Structural specialists responsible for architectural management and FE analysis take the thermal ‘maps’ from the thermal specialists, and predict thermal distortion and payload (angular) changes from nominal states. Often numerous thermal cases (mappings) are applied to the FE model to establish worst case scenarios for de-point. Key outputs from the FE model are normally angular shifts in pointing vectors at discrete payload locations or from discrete payload features. Calculated angular changes are then typically provided to mission system engineers for further data processing or as direct input into system budget allocation.
3. Mission specialists for supporting definition of the mission scenario and usually the final de-point budget management.
Historically verification via correlation of this analytic approach has not been rigorous but this needs to change. A growing demand is currently being seen to define verification tests and correlation approaches to enable a confident basis for such system level control.
The PhD shall support advancement of the industry state-of-the-art in all aspects that are associated with system requirements in order to predict and validate structural thermo-elastic stability.

There will be extensive theoretical and numerical modelling work of thermo-elastically controlled structures operating on orbit, and with associated terrestrial tests to implement and verify the theoretical findings.

Key subject areas or key words: structural dynamics, spacecraft, thermal loading, FEA, structural control, pointing accuracy, space mission architectures

This project is funded by Airbus (DS), and the University of Strathclyde Doctoral Training Centre

Duration of study: minimum 36 months

How to apply

If you are eligible and interested,  please apply by emailing a covering letter, full Curriculum Vitae and the names and contact details of at least two academic referees to Professor M Cartmell matthew.cartmell@strath.ac.uk.