Master Thesis - OUFTI-1

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Chapter 5 Complete FE analysis of OUFTI-1: Static, modal and random vibration 5.1 Introduction Through this chapter, a complete FE analysis of OUFTI-1 will be performed. Firstly, the modeling strategy for each of its components will be exposed. A selection will be realized between these components to choose which of them have a critical inuence on the global behavior of the entire satellite and so, have to be taken into account in the FE model, and which can be neglected to limit the modeling eorts. Then, three dierent analysis will be carried out: • A static analysis, where the satellite will be submitted to the static loads encountered during the launch phase. • A modal analysis, which will allow to obtain the natural frequencies of the satellite and to verify their fulllment of the ESA requirements. • A random vibration analysis, where the satellite will be submitted to a random vibration. This analysis is essential because the decision to accept the satellite on board Vega (or any other space launcher), is strongly based on its results. 5.2 Modeling strategy Through this section, the modeling strategy for the relevant components of the satellite will be exposed. It should be noted that this modeling is performed using the Samcef software. Firstly, the Catia model presented in chapter 2, is uploaded in the Samcef 101
environment. Then, this model is exploded in several parts to isolate each component. Finally, a behavior and a material are assigned to each of them and they are linked together using the assembly methods available in Samcef (the methods used must be as close as possible from the real connection between the two components to obtain accurate results). 5.2.1 Materials properties Firstly, the properties of the materials used for manufacturing the several components, are presented in a single table (see Table 5.1). This allows to avoid multiple repeatings of tables including these properties through this section. Afterwards, these materials will be just mentioned and their properties will not be reminded. It should be noted that these properties were found using the CES software. Materials Young's moduli (GP a) Poisson ratios Densities (kg/m 3 ) Al − 5052 H32 71.795 0.33675 2685 Al − 5754 69 0.33 2700 Al − 7075 T 6 72.5 0.33 2800 Al − 7075 T 73 71 0.33 2800 FR 4 20 0.3 2200 Stainless steel 205 0.3 7850 Table 5.1: Properties of the materials used in OUFTI-1 5.2.2 Main structure The main structure of OUFTI-1, which corresponds to the CSK structural parts, was modeled using shell components. Indeed, the thickness of the base and end plates (1.52 mm) and the one of the chassis (1.27 mm) are negligible with regard to their other dimensions (100 mm), which allows to use this type of modeling. All these components are made of Al − 5052 H32. The base and end plates are connected to the chassis by several M3 × 4 mm stainless steel screws. To model this type of connection in Samcef, the procedure is the following one: • A point (vertex) is placed at the center of the two holes (one on the considered plate and the other on the chassis). • These vertex are linked to the wire of their respecting hole using a "mean" assembly. This type of assembly determines the mean rotation and displacement of the nodes 102
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University of Liège Faculty of App
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Abstract OUFTI-1, standing for "Orb
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3.4 Initial idea . . . . . . . . .
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List of Figures 1.1 The Pumpkin's C
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4.18 MAC matrix using the simple me
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List of Acronyms ADCS Al AlNiCo ASI
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Thesis outline This thesis focuses
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of larger satellites. So, the CubeS
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1.2 OUFTI-1 project 1.2.1 Genesis O
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• XatCobeo (Vigo - Spain): Develo
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Chapter 2 OUFTI-1: Flight system co
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Figure 2.2: Product tree of OUFTI-1
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2.3.2 Solar panels The armor panels
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• We do not want to drill or manu
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In our case, because of the limited
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Figure 2.13: Magnetic eld obtained
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Figure 2.17: Pictures of the ADCS c
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consider the possibility of oshorin
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Figure 2.20: Exploded view of OUFTI
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I xx , I yy and I zz are called the
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Subsystem: Structure & Conguration
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Subsystem: Thermal Control Parts Co
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Chapter 3 Design of a new support f
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Figure 3.3: Batteries during and af
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The concept is the following one: F
Page 51 and 52: A test under vacuum conditions was
Page 53 and 54: Thermal Expansion (CTE) of the mate
Page 55 and 56: Figure 3.9: Classication by density
Page 57 and 58: The last property to determine is t
Page 59 and 60: • So, it was decided to use two t
Page 61 and 62: is to prevent the batteries' bulge.
Page 63 and 64: • Then, the thermostats, that wil
Page 65 and 66: Figure 3.23: Schematics of the cove
Page 67 and 68: • Other components, including the
Page 69 and 70: 3.9.3 Dynamic behavior Finally, it
Page 71 and 72: 3.10 Summary Through this chapter,
Page 73 and 74: Chapter 4 Electronic cards dynamic
Page 75 and 76: Figure 4.1: Example of manufacturin
Page 77 and 78: Figure 4.4: Illustration of the exp
Page 79 and 80: Figure 4.5: MAC between the two mod
Page 81 and 82: • Global mass/stiness smearing me
Page 83 and 84: 4.2.6 Modeling of the chassis A gen
Page 85 and 86: Q = ω k = 1 ω b − ω a 2 ζ ⇒
Page 87 and 88: Their study was based on the fact t
Page 89 and 90: Figure 4.14: Example of spacecraft
Page 91 and 92: Figure 4.15: Location of measuremen
Page 93 and 94: Figure 4.18: MAC matrix using the s
Page 95 and 96: 4.3.6 Application of the local mass
Page 97 and 98: ρ P C 104 connector = 10.12 × 10
Page 99 and 100: According to this particular shape,
Page 101: This is due to the fact that this c
Page 105 and 106: 5.2.4 Antenna support For the anten
Page 107 and 108: Components Young's moduli (GP a) Po
Page 109 and 110: Components Young's moduli (GP a) Po
Page 111 and 112: 5.3 Static analysis As described in
Page 113 and 114: Figure 5.9: Illustration of the com
Page 115 and 116: Figure 5.11: Maximal Von Mises stre
Page 117 and 118: Figure 5.12: First mode of OUFTI-1
Page 119 and 120: Figure 5.15: Precise PSD of Vega [5
Page 121 and 122: Chapter 6 Conclusions This master t
Page 123 and 124: provided for each method used. We h
Page 125 and 126: last versions of the Verication Con
Page 127 and 128: [13] Ph. LEDENT. "Design and Implem
Page 129 and 130: [40] "Dejond - Aluminum Catalog ".
Page 131 and 132: Appendix A Schemas of solar panels
Page 133 and 134: Appendix B Schemas of electronic ca
Page 135 and 136: Appendix C Fixations of the endless
Page 137 and 138: Appendix D Datasheet of the battery
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Master Thesis - OUFTI-1

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