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Digital archive of theses discussed at the University of Pisa

 

Thesis etd-09252007-083030


Thesis type
Tesi di laurea vecchio ordinamento
Author
BAGNOLI, LUCA
URN
etd-09252007-083030
Thesis title
Multibody analysis of solar array deployment using flexible bodies
Department
INGEGNERIA
Course of study
INGEGNERIA AEROSPAZIALE
Supervisors
Relatore Mengali, Giovanni
Relatore Salvetti, Attilio
Keywords
  • ADAMS
  • deployment
  • Multibody
  • solar array
  • solar panel
Graduation session start date
17/10/2007
Availability
Full
Summary
The solar panels represent the main device for collecting and converting solar energy into
electrical energy and they are widely used in space missions supplying the energy
necessary for both spacecrafts and payloads. To optimize the sun exposed surface the
panels are usually organized in wings configurations, that, stored during the launch,
deploy in the space at the beginning of the operative phase of the satellite.
This work of thesis focus on this deployment phase and on the associated dynamic
loads. The need of this investigation is connected to the strict requirements on the
deployment. Since we want to be sure of the complete deployment in every condition
with high margin of safety, the energy stored in the deployment mechanism is quite
oversized. This leads to the dynamic loads that we want to estimate.
The key topic of the thesis consists in the generation of a flexible multi-body model for
solar arrays deployment studies and analysis. The main aim of this model is the
verification and validation of a usually pre-existing rigid model used for the conceptual
studies of the deployment.
In this rigid model, generated directly in ADAMS environment, all the structural
stiffness is condensed in a small number of DOF (rotational springs located on the hinge
lines). It’s clear that this way of modelling does not cover higher frequency or side
dynamics effects. By the introduction of a flexible model we want to investigate these
effects and check the right working of the mechanism also in presence of deformation.
Optionally, using the flexible model, we can also have a first estimation of stresses and
strains due to the dynamics of the deployment.
The two main requirements for a flexible model are to be easy to generate and to be
compatible with the related rigid model. These two aspects are important to avoid
significant impact on the project budget. The flexible bodies are generated using the
user friendly interface of PATRAN (avoiding or minimizing manual inputs in
NASTRAN) and then importing this flexible bodies in an ADAMS adapted rigid model
(avoiding to re-built the flexible model from the beginning).
The first chapter of the thesis will show the theoretical background of the NASTRANADAMS
interface for the generation of flexible bodies. This theoretical part, even if not
strictly necessary for the final-user, is anyway important for the full comprehension of
some of the choices that will be adopted.
The second chapter will introduce and explain the main characteristics of a solar array
rigid model using BEPI COLOMBO MPO solar array and AMOS 3 solar array as
examples. The third chapter will focus on the generation of the flexible model using the
same two formers examples.
In chapter four the results of the two models will be compared and in the fifth chapter
the consequent conclusions will be drawn. In last chapter six will be shown other
possible fields of application of the flexible body modelling with ADAMS.
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