Apparatus for Characterizing Mixed Failure Modes in Cross Deck Pendants
Navy SBIR 2019.2 - Topic N192-077
NAVAIR - Ms. Donna Attick - email@example.com
Opens: May 31, 2019 - Closes: July 1, 2019 (8:00 PM ET)
TECHNOLOGY AREA(S): Materials/Processes
ACQUISITION PROGRAM: PMA251 Aircraft Launch & Recovery Equipment (ALRE)
OBJECTIVE: Design and develop an apparatus and methodology for rapid cycle testing of Cross Deck Pendants (CDPs) that is able to simulate, and then allow for the characterization of, the associated failure modes.
DESCRIPTION: Carrier aviation is dependent upon the ability to recover aircraft expeditiously and safely aboard ship. The arresting gear system aboard aircraft carriers relies on a steel cable to transfer the energy from the landing aircraft to the arresting gear engines located below the deck. The arresting gear cable is actually two separate cables, the CDP and the purchase cable, that are connected via a terminal and pin. The CDP is the portion of the cable that is stretched across the landing area and interfaces with the aircraft tailhook. It is replaced after approximately 125 cycles. The purchase cable is the portion of the cable that is reeved through the arresting engine below the flight deck, and has a much longer periodicity between replacements.
Three primary failure modes affect CDP service life: tailhook impact, hook slip, and final bend around the hook. Tailhook impact occurs at the moment of engagement with the cable; at this moment the CDP can accelerate from 0 to 155 knots almost instantaneously due to impact. Hook slip occurs when the aircraft lands “off-center” (i.e., at a distance either port or starboard of the landing area centerline). The arresting gear system will tend to pull the aircraft toward the centerline, and the tailhook will abrade the cable along the way. At the end of the arrestment, the CDP is bent around the tailhook with a low D/d ratio (diameter of the hook/diameter of the cable) in the final bend around the hook.
The Failure modes of the CDP are currently not fully understood and the development of a next generation CDP would benefit significantly from having knowledge of the CDP Failure Modes. Therefore, the Navy is interested in a test apparatus (machine) that can replicate these failure modes on a CDP in a real, physical environment, in order to
gain knowledge on the importance of each failure mode to CDP service life, and the interaction the failure modes have on each other. This knowledge will help craft requirements for a future improved CDP. Additionally, this test machine will be used as a cycle tester to qualify CDPs, reducing demand on existing, costly testing facilities. One machine for the three failure modes is preferred. However, the Navy will consider separate machines if one machine is unfeasible.
The machine must be able to isolate and test each failure mode, in a lab environment, both separately and combined, with varying degrees of each. Parameters are not constant. Cable tension on each side of the cable change quickly and by tens of thousands of pounds throughout each event. The goal will be to replicate tension time histories provided by the Government, as opposed to maintain a static peak cable tension. Impact speed will need to be controllable as well, according to each aircraft’s approach speed. Hook slip must be adjustable from zero to 10 feet. Hook points will need to be able to be swapped with other hook points since each aircraft has a unique tailhook.
Cable tension can be up to 110,000 lbs in the steel wire rope with an approximate diameter of 1.5 inches. Load from the tailhook can be up to 220,000 lbs. Engaging speed can be up to 155 knots. A cycle speed of 4 events per hour or greater is desired when tests are run concurrently with all three defined failure modes.
PHASE I: Define and develop a conceptual design with engineering and lifecycle cost analyses to prove the concept is feasible. The Phase I effort will include prototype plans to be developed during Phase II.
PHASE II: Develop and build a prototype of the system designed in Phase I. Provide a detailed design and engineering analyses consistent with a Critical Design Review. Include a demonstration of the full system operating in simulation, and verify the model with test data provided by the Government. Provide detailed cost estimate and a plan for manufacturing.
PHASE III DUAL USE APPLICATIONS: Build and test one unit. Install the unit at the Naval Air Warfare Center Aircraft Division, Lakehurst, New Jersey.
Wire rope has a wide range of applications in industry, including bridges, elevators, cranes, overhead hoists, ski- lifts, ship moorings, and off-shore oil rigs.
1. Sloan, F., Bull, S., & Longerich, R. “Design Modifications to Increase Fatigue Life of Fiber Ropes.” Proceedings of Oceans 2005, MTS/IEEE, Washington D.C., 2005. https://ieeexplore.ieee.org/document/1639856
2. Sloan, F., Nye, R., & Liggett, T. “Improving Bend-Over-Sheave Fatigue in Fiber Ropes.” Oceans, 2003, San Diego. https://ieeexplore.ieee.org/document/1283446
3. Wire Rope User's Manual, Fourth Edition, December 2005. The Wire Rope Technical Board: New York. http://www.wireropetechnicalboard.org/main_prod.html
KEYWORDS: Wire Rope; Cross Deck Pendant; Cable Testing; Cable Abrasion; Bend-Over-Sheave Performance; Arresting Gear