Utilization of Ultrasonic Consolidation in Fabricating Satelite Decking
Publication made available electronically January 13, 2012.
A fundamental investigation of the use of ultrasonic consolidation (UC) to produce deck panels for small satellites was undertaken. Several fabrication methods for producing structural panels and decking were analyzed. Because of its ability to create aluminum objects in an additive fashion, and at near-room temperatures, UC was found to be a powerful solution for creating highly integrated and modular satellite panels. It also allowed a lightweight and stiff deck to be fabricated without the use of adhesives.
A series of experiments were performed to understand the issues associated with creating a sandwich-type structure using UC. The experiments used a peel test apparatus to evaluate the bond strength for various geometric configurations and materials. Aluminum 3003 was chosen as the sole material constituting the deck panel. The honeycomb lattice was found to offer the best core configuration due to its ability to resist vibration from the sonotrode and provide adequate support for pressure induced by the sonotrode. Support materials for enhancing the bonding of the facings to the core were investigated but did not lead to implementation.
A CAD model was created to integrate the honeycomb core, facings, and modular bolt pattern into the ultrasonically consolidated structure. The model was used to develop a build procedure for fabricating the deck on the UC machine.
A finite element analysis was performed that used an equivalent properties method to represent the deck. The stiffness of a prototype deck was evaluated in a three-point bending test and the results were found to correlate with the finite element model. A sine sweep vibration test was then performed on the prototype deck panel to measure its natural frequencies.
Finally, a case study was performed on a deck built for the TOROID spacecraft. A final deck panel was designed using the results from the prototype. The deck included the USUSat bolt pattern, vented honeycomb, and a reinforced rim. The cost and benefits of the final deck panel versus traditional fabrication methods were outlined.