Master Thesis - OUFTI-1

More documents

Recommendations

Info

concerned. This particularity allows to model the fact that the screw is not rigidly xed to the structural parts, and that a set can occured. It is important to note that the denition of this type of assembly must be realized carefully. Indeed, one vertex is used as the reference point for the determination of the "mean" assembly. It is important that this point is selected rst and therefore, is dened as support 1. The vertex must be dened in the "Modeler" module as "not a datum point". The group of master nodes will be placed on support 2. No other parameters are required [56]. • Finally, the two vertex are linked together using a "xed" assembly, which allows to model the screw. This type of assembly joins the two parts rigidly together. The other components, such as the feet (normal and special ones), the deployment switch, ... were not taken into account because they do not aect signicantly the global behavior of the satellite. 5.2.3 Solar panels The solar panels, made of Al − 7075 T 73, were also modeled using shell components with a thickness of 1.5 mm. These solar panels will be connected to the dierent faces (+X, +Y , −Y , +Z and −Z) of the satellite using a specic glue: epoxy Stycast 2850 (with catalyst 24 LV), as alredy mentioned. To model this type of connection in Samcef, a "glue" assembly is used. This assembly is currently used when a glue is involved in a connection between two components. It establishes a linear relation between the nodes on support 1 and the faces of the elements on support 2 (as shown in Figure 5.1). The mesh is automatically adapted [56]. Figure 5.1: Illustration of a "glue" assembly [56] The solar cells and the electronic pads were not included in the model for the same reasons than before (negligible eect). 103
5.2.4 Antenna support For the antenna support, it was chosen to only model the support itself (made of Al − 5754). Indeed, due to their negligible mass, the antennas do not play an important role in the global behavior of the support, as well as the thermal knife and the "Dyneema" wire. However, owing to its complex geometry, this support can not be modeled using shell components. So, in this case, volume elements are used (in Samcef, it corresponds to apply the behavior of "exible volume" on the support). The xing method is the same as the one used for the solar panels. The support is connected to the face −X of the chassis using a "glue" assembly. 5.2.5 Electronic cards and battery support The modeling procedure for the electronic cards was discussed in chapter 4. In this chapter, it was noted that the best method to realize an accurate FE model of an electronic card is the homemade method, which uses the following simplications: • The light components are completely neglected. • The SMT components are modeled using the global mass smearing method. • The heavy components, such as the P C 104 connectors, are modeled using a detailed FE model. It was also noted that the electronic cards, due to their low thickness (1.7 mm), can be modeled using shell elements. So, this method will now be applied to each electronic card individually. The FM 430 card This card is presented in Figure 5.2. Applying the homemade method to this card is not so easy. Indeed, it can be seen that several heavy components are present on this card. Unfortunately, the properties of these components are not known so, a detailed FE model of these ones can not be realized. For this reason, it was decided that the P C 104 connector would be modeled using a detailed FE model, and the other components would be modeled using the global mass smearing method. The properties nally obtained for this card, are presented in Table 5.2. 104
Page 1 and 2:
University of Liège Faculty of App
Page 3 and 4:
Abstract OUFTI-1, standing for "Orb
Page 5 and 6:
3.4 Initial idea . . . . . . . . .
Page 7 and 8:
List of Figures 1.1 The Pumpkin's C
Page 9 and 10:
4.18 MAC matrix using the simple me
Page 11 and 12:
List of Acronyms ADCS Al AlNiCo ASI
Page 13 and 14:
Thesis outline This thesis focuses
Page 15 and 16:
of larger satellites. So, the CubeS
Page 17 and 18:
1.2 OUFTI-1 project 1.2.1 Genesis O
Page 19 and 20:
• XatCobeo (Vigo - Spain): Develo
Page 21 and 22:
Chapter 2 OUFTI-1: Flight system co
Page 23 and 24:
Figure 2.2: Product tree of OUFTI-1
Page 25 and 26:
2.3.2 Solar panels The armor panels
Page 27 and 28:
• We do not want to drill or manu
Page 29 and 30:
In our case, because of the limited
Page 31 and 32:
Figure 2.13: Magnetic eld obtained
Page 33 and 34:
Figure 2.17: Pictures of the ADCS c
Page 35 and 36:
consider the possibility of oshorin
Page 37 and 38:
Figure 2.20: Exploded view of OUFTI
Page 39 and 40:
I xx , I yy and I zz are called the
Page 41 and 42:
Subsystem: Structure & Conguration
Page 43 and 44:
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 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 and 102: This is due to the fact that this c
Page 103: environment. Then, this model is ex
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
show all

Master Thesis - OUFTI-1

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?