| Failure Analysis of Three Si3N4 Balls Used in Hybrid Bearings |
15 FEB 2003 |
29 pages |
| Authors:
M. J. O'Brien; N. Presser; E. Y. Robinson; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
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 | The rolling-element fatigue life of advanced hybrid material bearings consisting of silicon-nitride balls, REX20 tool-steel inner races, and CRU20 tool-steel outer races was measured under well-qualified laboratory testing. Multiple sets of four bearings (207H size) were tested using the least-of-four technique and sudden-death statistics to obtain a Weibull distribution based upon a bivariate model that accounted for load, time, and sample size. The Weibull distribution model shows that the advanced ... |
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| Silicon Nitride Hybrid Bearing Fatigue Life Comparisons |
15 JAN 1999 |
23 pages |
| Authors:
E. Y. Robinson; AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
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| Research to improve high-speed ball bearings for spacecraft applications has led to development of ceramic materials for bearing components, and the need to acquire sufficient fatigue life data to show the merits of various ceramic materials and fabrication processes, in comparison with the vast amount of steel bearing fatigue data acquired over many decades. In order to eliminate bias from such evaluations it is best to conduct ... |
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| Analysis of Wrinkles in Carbon-Carbon Composites |
OCT 81 |
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| Authors:
E. Y. Robinson; J. Jortner; AEROSPACE CORP EL SEGUNDO CA
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 | Wrinkles have been implicated in test failures and structural degradation. Localized effects on elastic properties can be very pronounced and need to be addressed when such features are present in components slated for testing or operational usage. A method for analyzing wrinkle anomalies is presented in this paper. The effect of the wrinkle is addressed by establishing compliance integrals across the 'disturbed' region and then developing a simplified mathematical wrinkle ... |
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| Mechanical Property Approximations of Carbon-Carbon Involute Cones |
JAN 80 |
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| Authors:
E. Y. Robinson; AEROSPACE CORP EL SEGUNDO CA
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| Rosette-type exit cone laminates are analyzed in this paper as idealized flat laminates having a continuous, uniform variation of fiber orientation, in direct proportion to thickness. Results provide formulas which may be used to assign properties to finite-element models of such laminated structures. Processing problems for such laminates, as experienced in the IUS program, are described briefly and recommendations made for improved analysis and reduced-risk processing. |
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| Developments of a Unique Graphite/Epoxy Antenna Subreflector, |
21 MAR 73 |
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| Authors:
E. Y. Robinson; R. A. Stonier; C. L. Lofgren
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| A subreflector for a conical main antenna reflector was designed and fabricated with graphite/epoxy material. The subreflector is a cylindrical paraboloid with demanding criteria for contour surface precision, high thermal stability, and sufficient structural capacity for intertial launch loads in axial and transverse directions. In addition, dynamic launch environments impose constraint on allowable natural frequencies. This application presents broad design requirements and novel fabrication constraints. (Author, modified). |
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| Development of a unique graphite/epoxy antenna subreflector. |
MAR 73 |
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| Authors:
E. Y. Robinson; R. A. Stonier; C. L. Lofgren; JET PROPULSION LAB PASADENA CALIF
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| Advanced concepts for large, furlable space antennas have led to an extensive development program with configurations utilizing conical main reflectors. The antenna subreflectors for these conical configurations have unusual geometries and new structural requirements. Structural efficiency of the conical antennas is improved through the use of fiber composites and a subreflector was designed and fabricated with graphite/epoxy material. This was sized to fit a subscale, 6-ft- diameter model. The subreflector ... |
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| Acoustic emission studies of large advanced composite rocket motor cases. |
FEB 73 |
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| Authors:
E. Y. Robinson; CALIFORNIA INST OF TECH PASADENA
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| Acoustic emission patterns were measured during pressure testing of advanced composite rocket motor cases made of boron/ epoxy and graphite/epoxy. Both accelerometers and high frequency acoustic emission tranducers were used, and both frequency spectrum and amplitude distri- bution were studied. The acoustic emission patterns suggest that precursor emission might be used in certain cases to anticipate failure. The technique of hold-cycle acoustic emission monitoring was also evaluated and could become ... |
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| On the elastic properties of fiber composite laminates with statistically dispersed fiber and ply orientation. |
FEB 73 |
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| Authors:
E. Y. Robinson; CALIFORNIA INST OF TECH PASADENA
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| Structural application of advanced composite filamentary materials requires lamination of the basic orthotropic plies into 'angle-ply' laminates. The resulting elastic and strength properties depend on the pattern of orientation and are influenced by inevitable errors and inaccuracy in placement of the angle plies. Misorientation results also from irregular displacements following processing at elevated temperatures. In addition, laminate properties are effected by dispersed fiber orientation. The effect on elastic properties of ... |
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| Estimating Weibull parameters for composite materials. |
OCT 72 |
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| Authors:
E. Y. Robinson; JET PROPULSION LAB PASADENA CALIF
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| This paper deals with the statistical analysis of strength and fracture of materials in general, with application to fiber composites. The 'weakest link' model is considered in a fairly general form, and the resulting equations are demonstrated by using a Weibull distribution for flaws. Failure and damage in a fiber-reinforced system are described. Some useful graphs are included for predicting the strength of such a system. Recent data on organic- ... |
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| a basic model for acoustic emission from fiber-reinforced material |
01 SEP 72 |
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| Authors:
E. Y. Robinson; JET PROPULSION LAB PASADENA CALIF
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| acoustic emission (ae) from fiber-reinforced composites can often be conveniently interpreted by use of normalized coordinates in graphical data display. many aspects of the shape of the acoustic emission pattern are invariant with the signal amplification ratio, and the use of normalized coordinates allows simultaneous comparison of ae pattern shapes from different experiments. in this paper, the first-order model of ae from fiber composites, based on filament breaking rates, is ... |
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| A BASIC MODEL FOR ACOUSTIC EMISSION FROM FIBER-REINFORCED MATERIAL. |
SEP 72 |
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| Authors:
E. Y. Robinson; JET PROPULSION LAB PASADENA CALIF
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| The first-order model of acoustic emission from fiber-reinforced composites, based on filament breaking rates, is cast into a normalized form useful for correlating experimental data. The general features of the normalized model are shown and compare favorably with available data. (Author, modified-PL) ANNOTATION: A basic model for acoustic emission from fiber-reinforced material. |
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| Analysis of stress-rupture data from S-glass composites. |
FEB 72 |
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| Authors:
E. Y. Robinson; T. T. Chiao; PRINCE ALBERT RADAR LAB (SASKATCHEWAN)
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| Stress-rupture data on S-glass multifilament yarn and S-glass-epoxy composites are obtained. Glass from different lots were used, and processing parameters were varied to demonstrate the effects of material variability. The statistical behavior of the data and rationale for classifying and interpreting the observed distributions are provided. The statistical patterns show that lifetime distributions are characteristically skewed. The normalized form of this distribution was used as a convenient analytical tool to ... |
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| A DESIGN PROCEDURE FOR BRITTLE MATERIAL UNDER BIAXIAL STRESS |
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| Authors:
E. Y. Robinson; PROTOTYPE DEVELOPMENT ASSOCIATES INC SANTA ANA CALIF
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Reports by Author
