Cyclic Loads Tests of Carbon Involute Solid Rocket Motor Outer Boot Ring Segments.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
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Cyclic Loads Tests of Carbon Involute Solid Rocket Motor Outer Boot Ring Segments On December23, 1987, a Solid Rocket Motor SRM nozzle Outer Boot Ring OBR failed at the end of the Development Motor 9 DM-9 test firing in Utah. This ring was constructed of carbon cloth phenolic CCP composite material laid in an involute arrangement. As a result, NASA selected the structural backup ring used in DM-8 to commence shuttle flights after the 1986 Challenger disaster. In an effort to explain the boot ring failure, a series of structural tests and analyses were devised for the DM-9 configuration ring. Among these was a series of cyclic loads tests of OBR segments. The immediate objective of the cyclic loads tests was to assess the cumulative damage, if any, from the cyclic loading incurred by gimballing the SRM nozzle during the DM-9 firing. To do this, six 30-in. segments were cut from an involute ring and instrumented with strain gages and EDIs. Three specimens were loaded directly to failure without cycling and the other three were loaded to failure after being cyclically loaded to simulate the DM-9 nozzle thrust vector control TVC duty cycle.
- Laminates and Composite Materials
- Solid Propellant Rocket Engines