Master Thesis - OUFTI-1

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Figure 4.20: MAC matrix using the local mass smearing method 4.3.7 Application of a homemade method Generally, the methods used in the previous sections, are applied to the entire PCB. However, as already mentioned in section 4.2.5, these methods can be particularized to the dierent categories of components and several methods can be applied on the same PCB. The homemade method described here is based on this concept. It considers the following simplications: • The light components are completely neglected. • The SMT components, including: the I 2 C − EEP ROM, the two MAX 890, the MSP 430, the Crystal 32.768 kHz and the JT AG connector, are modeled using the global mass smearing method. This solution was chosen because it is easier to apply than the local mass smearing method and, with regard to the mass contributions of these components, it brings the same level of accuracy. • The heavy components, including only the P C 104 connector, are modeled using a detailed FE model. This solution was chosen because, owing to its dimensions and its properties, the P C 104 connector plays an important role in the PCB dynamic response. So, it is better to model it entirely. To be able to create this particular model, the properties of this connector are necessary. Its mass is easily obtained by weighting it and has a value of 10.12 g, which leads to a density calculated in Equation 4.3.2 95
ρ P C 104 connector = 10.12 × 10−3 7.193 × 10 −6 = 1406.9234 kg/m3 (4.3.2) For its stiness, no static bend test was possible to perform. So, its value was xed based on reference [49], where the Young's modulus of an equivalent component was determined by test. So, the Young's modulus used in our FE model is 846 MP a. Applying this simplications on the FE model, the results obtained are presented in Table 4.7 and in Figure 4.21. Corresponding modes Frequency deviations (%) 1 15.29 2 17.33 Table 4.7: method Frequency deviations between corresponding modes using the homemade Figure 4.21: MAC matrix using the homemade method It can be remarked that this particular method is the one which gives the best results according to the MAC and the frequency deviations. For these last ones, the great dierences between the values obtained by the model and the ones resulting from the experimental test, can be easily explained. They are due to the fact that the stiness is ignored, and that ignoring the stiness is a conservative approach which underestimates the values of the natural frequencies. So, in the following chapter, this particular method will be applied to each electronic card of <strong>OUFTI</strong>-1 to obtain its complete FE model. 96
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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
Page 45 and 46: Chapter 3 Design of a new support f
Page 47 and 48: Figure 3.3: Batteries during and af
Page 49 and 50: 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: 4.3.6 Application of the local mass
Page 99 and 100: According to this particular shape,
Page 101 and 102: This is due to the fact that this c
Page 103 and 104: environment. Then, this model is ex
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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