equivalent total axial force, Feq, acting on the cap as shown in Equation 4.2 and Figure
4.6-C. This total force is then distributed equally and applied directly to the number of
nodes, n, on the outer circular edge at the end of the tube as shown in Equation 4.3 and
Figure 4.6-D.
Feq = P, Acap
n
Feq = F,
1i=1
F, Feq
n
(4.1)
(4.2)
(4.3)
Rigid Cap
Acap =7r2
Pi
ntHF-
Fabric Tube
i=1 (D)
Figure 4.6 Steps in representing internal pressure as pre-tension forces
4.1.2 Water Current Drag
Water flowing over the outer surface of the tube creates a drag force. Fluid
assumptions and equations are derived in Chapter 2. A programming do-loop was
Rigid Cap
(A)
(C)