Finite Element Analysis on the Lower Sustainer Bulkhead using Abaqus Purpose:

October 24, 2011

The purpose of this document is to provide a brief, graphical depiction of the finite element analysis performed on the lower sustainer bulkhead. This part is being modeled because its structural design is critical to the rocket. The bulkhead must withstand the thrust loads that the motor applies and it must transmit the thrust force to the rocket. Procedure: The finite element analysis is performed on three parts, which will be welded together during fabrication: 1. The lower sustainer bulkhead a. 5.75” outside diameter by 4.0” inside diameter b. To be cut out of a 3/16” Aluminum plate 2. The coupler tube between the sustainer and booster a. 5.75” outside diameter Aluminum tube with 1/8” wall thickness b. Height of 8” 3. The motor mount tube, which is welded to the inside circumference of the bulkhead a. 4.0” outside diameter Aluminum tube with 1/16” wall thickness b. Height of 4” for the model The assumptions and boundary conditions for the model are as follows: 1. The load applied to the top of the motor mount tube is modeled as a static load equal to the motor’s maximum thrust (1141.1 lbf), as supplied by Cesaroni Technologies (http://pro38.com/products/pro98/motor.php). The sustainer will use the 19318N3301-P motor, which has a total impulse of 19,318 N*s. 2. The bottom edge of the coupler tube has been fixed in space for the model. This will be similar to the test conditions that will be present when the model is tested in the laboratory. 3. The model takes advantage of quarter-symmetry, allowing a finer mesh to be used while reducing computer processing time. Results:

Figure 1 – Views of Quarter-Symmetry Assembly

Figure 2 – Mesh on the Bulkhead (uses linear 8-node elements)

Figure 3 – Biased Mesh on the Coupler Tube (biased to produce more elements near the loading)

Figure 4 – Plot of the Displacement Magnitude (in global x-y-z coordinate system) (in inches) Note: The magnitude of the deformation is highly exaggerated to show detail.

Figure 5 – Plot of the Displacement in the y-direction (a radial direction that is positive going from left to right across the picture above) (in inches) Note: The magnitude of the deformation is highly exaggerated to show detail.

Figure 6 – Plot of the Displacement in the z-direction (the axial direction, where displacement down is positive) (in inches) Note: The magnitude of the deformation is highly exaggerated to show detail.

Figure 7 – Plot of the Equivalent Von Misses Stress for the Undeformed Shape (in psi)

Figure 8 – Plot of the Equivalent Von Misses Stress for the Deformed Shape (in psi) Note: The magnitude of the deformation is highly exaggerated to show detail.

Figure 9 – Another Plot of the Equivalent Von Misses Stress for the Deformed Shape (in psi) Note: The magnitude of the deformation is highly exaggerated to show detail.

Figure 10 – A Final Plot of the Equivalent Von Misses Stress for the Undeformed Shape (in psi)