GLTRS--Glenn
TITLE AND SUBTITLE:
Modeling and Evaluation of Canted Coil Springs as High Temperature Seal Preloading Devices

AUTHOR(S):
Jay J. Oswald, Robert L. Mullen, Patrick H. Dunlap, Jr., and Bruce M. Steinetz

REPORT DATE:
September 2004

FUNDING NUMBERS:
WBS-22-794-40-4V

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
John H. Glenn Research Center at Lewis Field
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-14688

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, DC 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-2004-213189
AIAA-2004-3889

SUPPLEMENTARY NOTES:
Prepared for the 40th Joint Propulsion Conference and Exhibit cosponsored by AIAA, ASME, SAE, and ASEE, Fort Lauderdale, Florida, July 11-14, 2004. Jay J. Oswald and Robert L. Mullen, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-4901; Patrick H. Dunlap, Jr. and Bruce M. Steinetz, NASA Glenn Research Center. Responsible person, Jay J. Oswald, organization code 5950, 216-433-6411.

ABSTRACT:
Future reusable launch vehicles will require advanced structural seals. This includes propulsion seals along edges and hinge lines in hypersonic engines, and control surface seals for movable flaps and elevons on proposed reentry vehicles. Seals must remain in sealing engagement with opposing surfaces, for multiple missions, even though the seal gap may be opening and closing due to thermal and structural loads. To meet this requirement either the seals themselves must be resilient or there must be a resilient structural element behind the seals. Case Western Reserve University is working with NASA's Glenn Research Center to develop more resilient high temperature seal components and preloading devices. Results are presented for a finite element analysis of a canted coil spring that is being considered as a high temperature seal preloading device. This type of spring is a leading candidate due to its ability to provide nearly constant force over a large deflection. The finite element analyses were verified by comparing them to experimental results of canted coil springs of three different stiffnesses, measured at Glenn Research Center. Once validated the parameterized model was combined with a scripting algorithm to assess the effects of key spring design variables (wire diameter, coils per inch, cant amplitude, eccentricity, and spring width) on spring stiffness and maximum Von Mises stress to aid in subsequent design.

SUBJECT TERMS:
Seals; Canted coil; Spring; High temperature; Finite element method

NUMBER OF PAGES:
17

PDF AVAILABLE FROM URL:
2004/TM-2004-213189.pdf ( 3,098 KB )
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