Statistical aspects of coexisting fatigue failure mechanisms in OFHC copper
Axial load fatigue endurance distributions of annealed oxygen free high conductivity copper specimens with cold worked surface layer tested at four stress levels
AXIAL LOAD↗
SEARCH · Engineering Papers
Results for “endurance”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Advanced thermionic cathodes for Kaufman thrusters.
High endurance thermionic cathodes for Kaufman thrustors, discussing emissive coatings and emissive layer starvation
SURFACE LAYER↗
Evaluation of lubricants for high-temperature ball bearing applications.
High temperature lubricants for ball bearing applications, discussing bearing endurance and rolling-contact fatigue tests on synthetic paraffinic oil
LUBRICATING OIL↗
A review of lubrication of sliding and rolling element electrical contacts in vacuum
Summary data on deposition and endurance lives of thin metallic films used for lubricating sliding and rolling element electrical contacts in vacuum environments
Przybyszewski, J. S.↗
Results and problems of research on potassium vapor turbines.
Two stage potassium vapor turbine tests summary noting performance and endurance
Schnetzer, E.↗
Extreme temperature aerospace bearing lubrication systems Final report
Ball bearing endurance tests and lubricant film thickness measurements under conditions of high temperature, pressure, and speed
Peacock, L. A.↗
Reactor for nuclear extended range aircraft
High temperature liquid metal cooled nuclear reactor for military aircraft with long flight endurance and range
Orazio, F. D., Sr.↗
Erosion of metals by multiple impacts with water
Investigation determines - relation between impact velocity and minimum number of impacts producing visible erosion, relation between high frequency fatigue stresses and number of cycles to failure, water-hammer stresses relation to high frequency endurance limit, erosion rate as exposure time function, and correlates experimental data with recent theory.
Rudy, S. L.↗
Flat-conductor cable has rotary and linear flexibility
Report describes capabilities and limitations of flat-conductor cable /FCC/ relative to flexure in bending, folding, rotating, and extending, it also compares FCC mechanical and endurance characteristics with round-wire cable, and compares qualities of various types of insulation for FCC. Several configurations exemplify FCC flexibility.
Carden, J. R.↗
Antiwear and EP additive effects during rolling and spinning contact with a synthesized hydrocarbon oil
Synthesized hydrocarbon oil antiwear and extreme pressure additives effects on bearing spinning torque and endurance
Zaretsky, E. V.↗
Erosion of a three-stage potassium turbine
Three stage potassium vapor turbine for space systems electric power generation, discussing erosion and endurance tests
Kaplan, G. M.↗
Testing and performance simulation of an air- cooled thermoelectric module
Tubular compact air cooled thermoelectric module endurance and performance tests and computer simulation for space reactor power system
Merrifield, D. V.↗
SNAP-8 electrical generating system development program
The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology was demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.
Source record↗
SNAP-8 electrical generating system development program
The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology has been demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.
Source record↗
Alternator insulation evaluation tests
Tests were conducted to predict the remaining electrical insulation life of a 60 KW homopolar inductor alternator following completion of NASA turbo-alternator endurance tests for SNAP-8 space electrical power systems application. The insulation quality was established for two alternators following completion of these tests. A step-temperature aging test procedure was developed for insulation life prediction and applied to one of the two alternators. Armature winding insulation life of over 80,000 hours for an average winding temperature of 248 degrees C was predicted using the developed procedure.
Penn, W. B.↗
Magnetic perturbation inspection of inner bearing races
Approximately 100 inner race bearings were inspected nondestructively prior to endurance testing. Two of the bearings which failed during testing spalled at the sites of subsurface inclusions previously detected by using magnetic field perturbation. At other sites initially judged to be suspect, subsurface inclusion-nucleated cracking was observed. Inspection records and metallurgical sectioning results are presented and discussed.
Barton, J. R.↗
Application of polyimide actuator rod seals
Development of polyimide two-stage hydraulic actuator rod seals for application in high-performance aircraft was accomplished. The significant portion of the effort was concentrated on optimization of the chevron and K-section second-stage seal geometries to satisfy the requirements for operation at 450 K (350 F) with dynamic pressure loads varying between 200 psig steady-state and 1500 psig impulse cycling. Particular significance was placed on reducing seal gland dimension by efficiently utilizing the fatigue allowables of polyimide materials. Other objectives included investigation of pressure balancing techniques for first-stage polyimide rod seals for 4000 psig 450 K(350 F) environment and fabrication of a modular retainer for the two-stage combination. Seals were fabricated in 0.0254 m (1.0in.) and 0.0635 m (2.5in.) sizes and tested for structural integrity, frictional resistance, and endurance life. Test results showed that carefully designed second stages using polyimides could be made to satisfy the dynamic return pressure requirements of applications in high-performance aircraft. High wear under full system pressure indicated that further research is necessary to obtain an acceptable first-stage design. The modular retainer was successfully tested and showed potential for new actuator applications.
Watermann, A. W.↗
Grid-translation beam deflection systems for 5-cm and 30-cm diameter Kaufman thrusters
A 5-cm grid translation mechanism has been developed capable of 10 deg beam deflection. A 2026-hour endurance test was run at a preset 10 deg deflection angle and an extrapolated lifetime of better than 10,000 hours obtained. Response time data for grid translation are presented. Preliminary results for a 30-cm diameter system are given and results of a theoretical analysis of a dished grid system are discussed.
Lathem, W. C.↗