Master Thesis - OUFTI-1

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4.3.8 Sensitivity analysis During the description of the modeling strategy, it was highlighted that several parameters play an important role on the accuracy of the obtained FE model. In this section, the eect that a variation of some of these parameters causes on the PCB dynamic response, will be studied. Mass of the sensor used during the experimental test The rst analysis concerns the mass of the sensor used to realize the measurements during the test. Indeed, this sensor brings a local increase of mass and stiness on the PCB, just as each electronic component. To obtain accurate results, this fact has normally to be taken into account in our model, which is never the case when a FE model is realized. So, the question is: what is the real eect of the sensor on the PCB dynamic response To try to answer to this question, a sensitivity analysis will be performed by integrating sensors of several mass in our model. Then, the shape of the fourth mode of the OBC 2 card will be studied for 3 cases: a sensor of 0.2 g (as the sensor used in our case), one of 1 g and the last of 2 g. To realize this, a concentrate mass is added to the model. However, this mass has to be placed at a strategic point to obtain results which highlight its inuence on the mode shape. Indeed, if this mass was placed on a vibration node, nothing could be observed because it would not be excited. So, to realize this choice, the initial shape of the fourth mode is necessary. This one is given in Figure 4.22. Figure 4.22: Initial shape of the OBC 2 card's fourth mode 97
According to this particular shape, it was chosen to place the sensor at the level of the measurement point 1 (see Figure 4.15), which is situated in one of the two corners on the opposite side of the P C 104 connector, because it is this part of the electronic card which presents the greatest deformations and so, which participates the most to this mode. Table 4.8 presents the natural frequencies obtained in each case and their deviations with regard to the initial one, and Figure 4.23 shows the eect on the mode shape. Cases Natural frequencies (Hz) Frequency deviations (%) Initial 907.68 / Sensor of 0.2 g 893.81 1.53 Sensor of 1 g 862.66 4.96 Sensor of 2 g 847.62 6.62 Table 4.8: Natural frequencies obtained by adding sensors of several mass to the FE model Figure 4.23: Mode shapes obtained by adding sensors of several mass to the FE model 98
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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
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 and 96: 4.3.6 Application of the local mass
Page 97: ρ P C 104 connector = 10.12 × 10
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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