Figure 2. Wiring Diagram for CBUSH, PBUSH, PBUSHT and TABLED2
for a Coulomb Damping Description.
The model setup is shown below in figure 3.  It is reduced to a single degree of
freedom problem by constraining the 2 nodes as shown. The damping and stiffness are
both defined by a single CBUSH element. A short duration triangular pulse of 2ms is
applied to the system.
Figure 3. Analysis model schematic
Coulomb Damping - Page 2
The data is input into Nastran using a TABLED1 entry as shown in Figure 2. The presence
of the PBUSH1 referenced for damping overrides the damping on the PBUSH entry which is
set as 5% critical. The small non vertical slope is seen by the -0.0001 and +0.0001 data
pairs.
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