Thesis offer

Mechanical design of stratospheric balloons: numerical and experimental approach

CNES has been working for several years to develop predictive mechanical models designed to improve the performance and reliability of balloon envelopes. The “Institut de Recherche Dupuy de Lôme” (IRDL Lorient) supports CNES in this development with a finite element processing tool (Herezh++) adapted to inflated structures with large displacement.

The aim of this PhD work is to investigate the status of numerical and experimental aspects of inflated balloon behavior in order to improve these simulations.
This research will provide a relevant contribution to simulation tools, taking advantage of balloon research and development activities.

Bibliography activity phase will provide a scientific glance on the latest developments in this domain. Through this work experimental data and results will be collected then compared with the outcome of the work that needs to be carried out.
A first objective of the study will be the analysis and development of experimental procedures. Based on small- sized specimens of inflated structures, we seek to identify behaviors laws and to study, then validate, the simulations. The appropriated measurements to that type of structure will be an important part of the work, especially at low temperatures.

The second objective is dedicated to numerical simulations in order to expand and to feed the theoretical bases. Several ideas could be considered as:

  • Assembly of existing tools (algorithms) in order to imagine new composite scenarios (dynamic relaxation combined with the implicit calculation, for instance),
  • Research of a method to take into account the local buckling,
  • Study of a better solution to introduce plastic anisotropic material behavior in Herezh and to use the method for complex laws,
  • Pleat management (self-contact),
  • Fluid-structure coupling.

In addition to this PhD, the correct design of CNES balloons requires the establishment of a test program to characterize the material behavior used in modelling, which is a part of research activity in CNES. These tests will not be directly carried out by the PhD student; nevertheless he will be part of design reviews, analysis and prospecting phases.

This PhD work is an important component of a set of studies decided by CNES to improve knowledge on the design and prediction of our balloon’s behavior. The results will contribute to the improvement of CNES’ skills in this domain.

Profil recherche

  • Highly motivated by finite element numerical simulation, he (she) has a strong background and scientific experience in mechanics of structures and materials. Skills in nonlinear constitutive laws are welcome as well as interest in aerospace engineering. He (she) appreciates working in a team. He (she) is autonomous motivated and has initiative. He (she) writes and speaks English fluently

Website

https://cnes.fr/fr/les-ressources-humaines-du-cnes/dimensionnement-de-ballons-stratospheriques-approche- numerique-et

Contacts

Host laboratory : Institut de Recherche Dupuy de Lôme (IRDL)
PhD/research supervisors: RIO Gérard (gerard.rio@univ-ubs.fr), LAURENT Hervé (herve.laurent@univ-ubs.fr)
Offer CNES supervisor : GUIGUE Pascale

 

 

Apply

To apply for this offer, we invite you to contact the PhD/research supervisor and complete with the co- financing part of the online form (Reply to the offer) by March 31, 2017.

 

 

 

Posted in Actualités.