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At least 163 records · Page 9

Predicting the velocity and azimuth of fragments generated by the range destruction or random failure of rocket casings and tankage

A calculational method is described which provides a powerful tool for predicting solid rocket motor (SRM) casing and liquid rocket tankage fragmentation response. The approach properly partitions the available impulse to each major system-mass component. It uses the Pisces code developed by Physics International to couple the forces generated by an Eulerian-modeled gas flow field to a Lagrangian-modeled fuel and casing system. The details of the predictive analytical modeling process and the development of normalized relations for momentum partition as a function of SRM burn time and initial geometry are discussed. Methods for applying similar modeling techniques to liquid-tankage-overpressure failures are also discussed. Good agreement between predictions and observations are obtained for five specific events.

Eck, Marshall↗

Automated Inspection of the RSRM Case O-Ring Seal Surface

An automated inspection system has been developed to inspect the o-ring sealing surfaces on the Space Shuttle reusable solid rocket motor (RSRM) case segment joints. A laser digitizing system is used to create a three dimensional map of the o-ring sealing surfaces. This data is analyzed for any irregularities, which are noted for further inspection and disposition. This paper describes both the hardware and the software used to gather data as well as the methods developed to analyze the data. The RSRM is assembled from four casting segments. Each of the field joints between these segments is sealed with three o-rings. These o-rings are critical for the proper operation of the motor. After launch the booster segments are recovered and reused. As part of the refurbishment process the o-ring sealing surfaces are inspected for any irregularities. The system developed uses a combination of commercial and customized hardware and software. The system uses two computer systems in a real time environment to control a laser, an XYZ precision table, and case rotation and position information. The system is capable of inspecting both the tang end and the clevis end of the RSRM field joint. The o-ring grooves and flat sealing surfaces are inspected.

ODell, Keith P.↗

Identification and management of filament-wound case stiffness parameters

The high specific strength and the high specific modules made graphite epoxy laminate an expedient material substitute for the Shuttle Solid Rocket Motor steel case to substantially increase the payload performance without increasing the composite case axial growth during thrust build up which was constrained to minimize liftoff excitation effects on existing structural elements and interfaces. Parameters associated with axial growth were identified for quality and manufacturing controls. Included is an innovative method for experimentally verifying extensional elastic properties on a laminate pressurized test bottle.

Verderaime, V.↗

A Preliminary Investigation on the Destruction of Solid-Propellant Rocket Motors by Impact from Small Particles

An investigation was conducted to determine whether solid-propellant rocket motors could be ignited and destroyed by small-particle impacts at particle velocities up to a approximately 10,940 feet per second. Spheres ranging from 1/16 to 7/32 inch in diameter were fired into simulated rocket motors containing T-22 propellant over a range of ambient pressures from sea level to 0.12 inch of mercury absolute. Simulated cases of stainless steel, aluminum alloy, and laminated Fiberglas varied in thickness from 1/50 to 1/8 inch. Within the scope of this investigation, it was found that ignition and explosive destruction of simulated steel-case rocket motors could result from impacts by steel spheres at the lowest attainable pressure.

Carter, David J., Jr.↗

Rocket-motor spin-test apparatus

Rocket motor spin test apparatus capable of subjecting solid rocket motors to dynamic spin or roll environments encountered in flight

FLIGHT TEST INSTRUMENT↗

Solid propellant rocket motor and method of making same

A method is described for making a solid propellant rocket motor having a specific concavity formed within the fuel charge. A mandrel with an aperature wider than that of the casing is inserted within the motor casing and a solidifiable propellant cast above the mandrel. The mandrel is removed after the propellant is cured.

Thibodaux, J. G., Jr.↗

Numerical techniques for solving nonlinear instability problems in smokeless tactical solid rocket motors

The selection of a satisfactory numerical method for calculating the propagation of steep fronted shock life waveforms in a solid rocket motor combustion chamber is discussed. A number of different numerical schemes were evaluated by comparing the results obtained for three problems: the shock tube problems; the linear wave equation, and nonlinear wave propagation in a closed tube. The most promising method--a combination of the Lax-Wendroff, Hybrid and Artificial Compression techniques, was incorporated into an existing nonlinear instability program. The capability of the modified program to treat steep fronted wave instabilities in low smoke tactical motors was verified by solving a number of motor test cases with disturbance amplitudes as high as 80% of the mean pressure.

Baum, J. D.↗

The full-scale process and design changes for elimination of insulation edge separations and voids in tang flap area

Qualification of the full-scale process and design changes for elimination of redesigned solid rocket motor tang nitrile butadiene rubber insulation edge separations and voids was performed from 24 March to 3 December 1990. The objectives of this test were: to qualify design and process changes on flight hardware using a tie ply between the redesigned solid rocket motor steel case and the nitrile butadiene rubber insulation over the tang capture features; to qualify the use of methyl ethyl ketone in the tang flap region to reduce voids; and to determine if holes in the separator film reduce voids in the tang flap region. The tie ply is intended to aid insulation flow during the insulation cure process, and thus reduce or eliminate edge unbonds. Methyl ethyl ketone is intended to reduce voids in the tang flap area by providing better tacking characteristics. The perforated film was intended to provide possible vertical breathe paths to reduce voids in the tang area. Tang tie ply testing consisted of 270 deg of the tang circumference using a new layup method and 90 deg of the tang circumference using the current layup methods. Tie ply process success was defined as a reduction of insulation unbonds. Lack of any insulation edge unbonds on the tang area where the new process was used, and the presence of 17 unbonds with the current process, proves the test to be a success. Successful completion of this test has qualified the new processes.

Danforth, Richard A.↗

Development and application of contamination technology for MSFC managed space systems

The second annual report on the development and application of contamination technology for MSFC managed space systems covering the period from 10 Dec. 1992 to 10 Dec. 1993 is presented. During this time period, studies were concluded which proved that in-process corrosion protection is not required during Redesigned Solid Rocket Motor (RSRM) case processing. Also completed were a series of tests evaluating the effects of environmental exposure and contamination on 2219-T87 aluminum (Space Shuttle External Tank) OSEE response and bonding properties. Correlations were developed between OSEE response, contamination type/level, and primer adhesion. The results showed that the wet tape and water break free tests currently employed during ET processing may not detect bond affecting levels of some potential contaminants; however, the contaminants were detected with OSEE analysis. Finally, exposure/contamination studies were initiated with HP9-4-30 steel. HP9-4-30 was selected for evaluation because it represents a class of metals commom to MSFC managed space flight systems which are less prone to oxidation than D6AC steel or aluminum.

Source record↗

Models Extracted from Text for System-Software Safety Analyses

This presentation describes extraction and integration of requirements information and safety information in visualizations to support early review of completeness, correctness, and consistency of lengthy and diverse system safety analyses. Software tools have been developed and extended to perform the following tasks: 1) extract model parts and safety information from text in interface requirements documents, failure modes and effects analyses and hazard reports; 2) map and integrate the information to develop system architecture models and visualizations for safety analysts; and 3) provide model output to support virtual system integration testing. This presentation illustrates the methods and products with a rocket motor initiation case.

Malin, Jane T.↗