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Orion Parachute Riser Cutter DevelopmentThis paper presents the tests and analytical approach used on the development of a steel riser cutter for the CEV Parachute Assembly System (CPAS) used on the Orion crew module. Figure 1 shows the riser cutter and the steel riser bundle which consists of six individual cables. Due to the highly compressed schedule, initial unavailability of the riser material and the Orion Forward Bay mechanical constraints, JSC primarily relied on a combination of internal ballistics analysis and LS-DYNA simulation for this project. Various one dimensional internal ballistics codes that use standard equation of state and conservation of energy have commonly used in the development of CAD devices for initial first order estimates and as an enhancement to the test program. While these codes are very accurate for propellant performance prediction, they usually lack a fully defined kinematic model for dynamic predictions. A simple piston device can easily and accurately be modeled using an equation of motion. However, the accuracy of analytical models is greatly reduced on more complicated devices with complex external loads, nonlinear trajectories or unique unlocking features. A 3D finite element model of CAD device with all critical features included can vastly improve the analytical ballistic predictions when it is used as a supplement to the ballistic code. During this project, LS-DYNA structural 3D model was used to predict the riser resisting load that was needed for the ballistic code. A Lagrangian model with eroding elements shown in Figure 2 was used for the blade, steel riser and the anvil. The riser material failure strain was fine tuned by matching the dent depth on the anvil with the actual test data. LS-DYNA model was also utilized to optimize the blade tip design for the most efficient cut. In parallel, the propellant type and the amount were determined by using CADPROG internal ballistics code. Initial test results showed a good match with LS-DYNA and CADPROG simulations. Final paper will present a detailed roadmap from initial ballistic modeling and LS-DYNA simulation to the performance testing. Blade shape optimization study will also be presented.
Document ID
20100039628
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Oguz, Sirri (NASA Johnson Space Center Houston, TX, United States)
Salazar, Frank (NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 25, 2013
Publication Date
July 31, 2011
Subject Category
Mechanical Engineering
Report/Patent Number
JSC-CN-24140
JSC-CN-21998
Meeting Information
Meeting: AIAA Joint Propulsion Conference
Location: San Diego, CA
Country: United States
Start Date: July 31, 2011
End Date: August 3, 2011
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 644423.06.31.03.13.10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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