Strength Analysis - Finite Element Analysis for Satellite Structures - page 96

frame, and 12 nodes divided into two circles representing the connection with
the battery bracket.
• Upper frame module: 96 nodes representing the connection of the frame with the
base plate, 12 nodes representing the connection of the battery bracket with the
base plate, and 96 nodes divided into eight circles representing the connection
with the basis plate module.
• Basis plate module: 96 nodes representing the connection with the upper frame,
96 nodes divided into eight circles representing the connection with the basis
walls module, 24 nodes divided into four circles representing the connection of
the plate with the basis walls through four bolts, and 12 nodes divided into two
circles representing the connection of the diagonal struts with the basis walls
through two bolts.
• Basis walls module: 132 nodes representing the connection with the basis plate
module, 96 nodes divided into eight circles representing the connection with the
lower frame module, and two nodes located at the same wall representing two
points of the base connections for the equipment model of Power Conditioning
Unit (PCU) and Cell Leveling Unit (CLU). In the use pass phase, this equipment
model is created as a virtual element during building the satellite model.
• Lower frame module: 96 nodes representing the connection with the basis walls
module, 96 nodes divided into eight circles representing the connection with the
mounting plate module, and two nodes located at the same wall representing the
other two points of the base connections for the equipment model of PCU and
CLU.
• Mounting plate module: 96 nodes divided into eight circles representing the
connection of the plate with the lower frame module.
Table 4.1 lists the total number of elements and nodes used to mesh each
structural module, in addition to the total number of selected master DOF. As such,
the total number of master DOF is 3,819 associated with 1,273 nodes. Each
selected node has only three DOF (U x , U y , and U z ) because they belong to the
ANSYS solid element ''SOLID92''. It has a quadratic displacement behavior and
is well suited to model irregular meshes. SOLID92 is defined by 10 nodes having
three translational DOFs at each node.
4.8 Global Finite-Element Model of Small Sat
The entire finite-element model of Small Sat is generated during use the pass
phase. It is used in static, modal, and dynamic analyses. It consists of the seven
superelement modules of the primary structure with the launch vehicle adapter and
a virtual element (nonsuperelement). The virtual part is the equipment model of
the PCU and the CLU. They are modeled together as a single part. This virtual part
is modeled as a pyramid with zero-density elements like all other satellite