1.40E+07
1.20E+07
1.00E+07
0-
S8.00E+06
n Maximum Stress
S6.00E+06 -
~m Minimum Stress
a 4.00E+06
3 2.00E+06
0.OOE+00
-2.00E+06
0 2 4 6 8 10 12 14
Tube Length (m)
Figure 4.18 Longitudinal bending stress results for verification model with 0.5 m/s flow
velocity
4.1.5 Verification Model Conclusion
The results from the verification model show the merged shell41 and shell63
elements acceptably model the tension-only tubing material. The Saint-Venant's
principle effect is specific to the boundary conditions and geometry of the verification
model and is not applied elsewhere. The drag loading and boundary condition
applications are acceptable and accurately model the actual conditions.
4.2 Cage Simulation Process
The actual tubes, when assembled as a cage, have rigid end caps with hose clamps
constraining each end. Based on the geometry of the cage, the tube can flex and extend
longitudinally. Internally, the tube contains pressurized air to maintain inflation. The
external loading on the tube is a distributed drag force caused by a cross-flowing water
current.