Satellite FEM materials and properties

IV.1.2 Satellite FEM materials and properties

In the satellite FE model, only seven material cards are defined. The most relevant parameters of material cards are given in Tables IV.1.1, IV.1.2 and IV.1.3.

Table IV.1.1: Isotropic materials used in the finite element model (MAT1 property cards).


Material name	MID	$E$ (GPa)	$ν$	$α$ ( $K^{- 1}$ )	$ρ$ ( ${kg/m}^{3}$ )


Al-7075-T7351	2	72.1	0.33	$23.6 10^{- 6}$	2796.0

Al-7010-T7451	1	71.7	0.33	$23.6 10^{- 6}$	2820.0

Al-2024-T3 clad	3	69.0	0.33	$23.6 10^{- 6}$	2768.0

(thermo-elastic)	5001	72.1	0.33	$23.6 10^{- 6}$	0.0

Table IV.1.2: 3D anisotropic materials used in the finite element model (MAT9 property cards).


Material type	Honeycomb 50	Honeycomb 72


MID	5	6

$G_{11}$ (MPa)	0.670	0.760

$G_{22}$ (MPa)	0.670	0.760

$G_{33}$ (MPa)	669.0	1276.0

$G_{44}$ (MPa)	0.207	0.310

$G_{55}$ (MPa)	138.0	193.0

$G_{66}$ (MPa)	310.0	483.0

$ρ$ ( ${kg/m}^{3}$ )	50	72

$α$ ( $K^{- 1}$ )	$23.6 10^{- 6}$	$23.6 10^{- 6}$

Table IV.1.3: 2D anisotropic materials used in the finite element model (MAT8 property card).


Material type	Honeycomb 50 2D	CFRP 2D


MID	4	10000

$E_{1}$ (MPa)	0.500	290000

$E_{2}$ (MPa)	0.500	5600

$ν_{12}$	0.3	0.33

$G_{12}$ (MPa)	0.500	3000

$G_{1 Z}$ (MPa)	310.0	1100

$G_{2 Z}$ (MPa)	138.0	1100

$ρ$ ( ${kg/m}^{3}$ )	50	1670

$α_{1}$ ( $K^{- 1}$ )	$23.6 10^{- 6}$	$- 1 10^{- 6}$

$α_{2}$ ( $K^{- 1}$ )	$23.6 10^{- 6}$	$31 10^{- 6}$

$S_{1 t}$ (MPa)	0.050	1600

$S_{1 c}$ (MPa)	0.050	500

$S_{2 t}$ (MPa)	0.050	25

$S_{2 c}$ (MPa)	0.050	140

$S_{s}$ (MPa)	0.050	55

All CBAR elements receive PBARL properties:

For the traversing elements representing the inserts in sandwich panels, one assumes a cylinder of 16 mm diameter. The material is Al 7010 T7451.
The bars of metallic frame receive Al 7010 T7351 material and have a tubular cross-section with 26 mm and 30 mm internal and external diameters respectively.
The bars of struts receive Al 7010 T7351 material and have a tubular cross-section with 46 mm and 50 mm internal and external diameters respectively.
Finally, when RBE2 elements are replaced by very stiff CBAR elements for thermo-elastic calculations, one attributes the fake material 5001 to the CBAR elements. This material is equivalent to Al 7010 T7351 but has no density. The bar cross-section is assumed to be a rod of 30 mm diameter.

All skins, except those of bottom panel, are made of Aluminum 2024 T3 and have a thickness of 0.5 mm. The honeycomb used in sandwich panels has a density of 50 ${kg/m}^{3}$ . Only in the +Z panel of the box a 72 ${kg/m}^{3}$ honeycomb has been used. The bottom panel is modeled with surface elements, and has correspondingly a PCOMPG property card (PID=6). Each skin of the bottom sandwich panel is made of CFRP laminated material with plies 0.1 mm thick. The properties are defined as follows:

PCOMPG    6                  50.779    30.+6    HILL    20.        0.
            2008     10000  1.-4      0.        YES
            2007     10000  1.-4      45.      YES
            2006     10000  1.-4     -45.      YES
            2005     10000  1.-4      90.      YES
            2004     10000  1.-4      90.      YES
            2003     10000  1.-4     -45.      YES
            2002     10000  1.-4      45.      YES
            2001     10000  1.-4      0.        YES
            100      4        .0284     0.        YES
            3001     10000  1.-4      0.        YES
            3002     10000  1.-4      45.      YES
            3003     10000  1.-4     -45.      YES
            3004     10000  1.-4      90.      YES
            3005     10000  1.-4      90.      YES
            3006     10000  1.-4     -45.      YES
            3007     10000  1.-4      45.      YES
            3008     10000  1.-4      0.        YES

For sandwich panels modeled with solid elements, the honeycomb is oriented in such a way that the direction Z is perpendicular to the panel. Direction X is vertical for vertical panels and oriented towards +X of coordinate system 1001 for horizontal panels.

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