Master Thesis - OUFTI-1

Components
Mass (g)
Box 27.33
Cover 19.24
4 screws M3 × 8 mm 4 × 0.465 = 1.86
4 spacers 4 mm 4 × 0.0775 = 0.31
4 spacers 19 mm 4 × 0.3575 = 1.43
2 batteries KOKAM SLB 603870H 2 × 33 = 66
4 wires 4 × 2 = 8
2 heaters 2 × 1.5 = 3
4 thermostats 4 × 0.2125 = 0.85
8 wires 8 × 1.25 = 10
Thermal insulator 0.08
Total 138.1
Table 3.6: Necessary mass budget
This budget is well lower than the available mass budget, which is of 153.29 g. So, our
design is valid with regard to the mass.
3.9.2 Static loads
Then, the structural integrity of the support under static loads at which it will be
submitted during the launch phase, must be veried.
For this, some FE analysis have to be performed. To limit the modeling eorts, only
the relevant structural parts will be considered. The modeling strategy for each part of
the support is:
• The box and the cover of the support are exible volumes made of Al − 7075 T 6.
The properties of this material are:
Young's modulus: E = 72.5 GP a
Poisson ratio: ν = 0.33
Density: ρ = 2800 kg/m 3
• The batteries, which are also exible volumes, weight 32 g and have a volume of
1.482 × 10 −5 m 3 in nominal conditions, which lead to a density of 2159.25 kg/m 3 .
However, their Young's modulus can not be estimated and is not provided in the
datasheets. To determine it, some static bench tests would be necessary but, in our
case, these components will be represented by increasing the density of the support
inside the area normally occuped by the batteries.
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