Tesi etd-10192021-104652 |
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Tipo di tesi
Tesi di laurea magistrale
Autore
GOTTINI, DANIELE
URN
etd-10192021-104652
Titolo
Ariel Mission: Testing the Pre-flight Primary Mirror via FEA
Dipartimento
INGEGNERIA CIVILE E INDUSTRIALE
Corso di studi
INGEGNERIA AEROSPAZIALE
Relatori
relatore Prof. Marcuccio, Salvo
relatore Prof. Pace, Emanuele
tutor Ing. Del Vecchio, Ciro
tutor Ing. Scippa, Antonio
relatore Prof. Pace, Emanuele
tutor Ing. Del Vecchio, Ciro
tutor Ing. Scippa, Antonio
Parole chiave
- analysis
- Ansys
- ansys
- Ariel
- ariel
- fem
- FEM
- mirror
Data inizio appello
23/11/2021
Consultabilità
Non consultabile
Data di rilascio
23/11/2024
Riassunto
The objective of the thesis is to study the ground testing phase of the main mirror of the ARIEL telescope.
Tests on the prototype of the mirror (PTM) underlined an unexpected deformation of the reflecting surface exceeding a peek to valley of 1µm, this led to the need of better analysing the execution of said tests to find out faults and correct the setting for future tests on the final prototype M1.
First of all the PTM was taken into consideration and a free-free modal analysis was carried out on a shell model of the mirror and compared to pre-existing analyses to evaluate the goodness of the model and the set up.
After this, static structural analyses with different supporting configurations were done: they underlined the need of more carefully explain and document the setting up of the tests due to significant differences of the results depending not only on the configuration but also on the sequence of operation to reach the final setting. Additional studies were also performed to evaluate different settings for future tests. Some doubts rose when moving from bonded to frictional connections between the mirror outer edge and the supporting cylinders; to solve them, the analysis moved to the dynamic domain, but the steady state results turned out to be in line with the static structural with calculation times order of magnitude larger and so it was discarded.
In the last phase the focus shifted on the M1 model: three configurations were considered using a shell model for the mirror, the results were evaluated using MatLab to subtract the effect of rigid tilt of the reflective surface. Two different mirror models were considered and the results were submitted to the optical team for successive studies.
Tests on the prototype of the mirror (PTM) underlined an unexpected deformation of the reflecting surface exceeding a peek to valley of 1µm, this led to the need of better analysing the execution of said tests to find out faults and correct the setting for future tests on the final prototype M1.
First of all the PTM was taken into consideration and a free-free modal analysis was carried out on a shell model of the mirror and compared to pre-existing analyses to evaluate the goodness of the model and the set up.
After this, static structural analyses with different supporting configurations were done: they underlined the need of more carefully explain and document the setting up of the tests due to significant differences of the results depending not only on the configuration but also on the sequence of operation to reach the final setting. Additional studies were also performed to evaluate different settings for future tests. Some doubts rose when moving from bonded to frictional connections between the mirror outer edge and the supporting cylinders; to solve them, the analysis moved to the dynamic domain, but the steady state results turned out to be in line with the static structural with calculation times order of magnitude larger and so it was discarded.
In the last phase the focus shifted on the M1 model: three configurations were considered using a shell model for the mirror, the results were evaluated using MatLab to subtract the effect of rigid tilt of the reflective surface. Two different mirror models were considered and the results were submitted to the optical team for successive studies.
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