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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"Ball bearings"”.
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Assembly Optimization for Double Row Ball Bearings
… on optimal assembly methods for double row ball bearings. As with common single row bearings, double row ball bearings, consist of four general components, namely, an inner ring, an outer ring, a complement of balls and a cage or retainer to keep the balls separate. Unlike single row …
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Reaction Wheel Ball Bearings Microvibration Source Characterisation
… misalignments and imperfections affecting the ball bearing components, are some of the main causes that generate microvibrations disturbances onboard, affecting the pointing stability of the satellite line-of-sight. The work presented in this thesis aims to characterize the RW disturbance …
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Predicting the dynamic behavior of rotor systems on ball bearings
… dynamic behavior of a rotor system supported by ball bearings are presented. Two computer programs were developed. The first uses a transfer matrix technique to compute rotor natural frequencies as a function of bearing stiffness. The second is a bearing analysis program which is used to …
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Air-oil mist lubrication of small bore ball bearings at high speeds
… groove and angular con tact 25 and 30 mm bore ball bearings were tested to high speeds using air-oil mist lubrication. Test conditions included cooling air flow rates of 1.5, 3.0, and 6.0 scfm (0.05, 0.10, and 0.20 kg/min), thrust loads of 50, 75, and 100 lb (222, 334, and 445 N), and a …
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Development of a pneumatic sensor for measuring the torque of instrument ball bearings
… on the operational characteristics of instrument ball bearings, a great majority have been in accordance with MIL-STD-206. Since tests in compliance with this specification determine bearing quality or rate bearings comparatively, nothing was known of the operational characteristics of the …
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Effects of controlled vibration induced gapping on the torque performance of lubricated ball bearings
Ball bearings that are not sufficiently preloaded may be subjected to gapping and transient high contact stresses during launch. Despite the fact that such phenomena may cause bearing damage or degrade torque performance and lubricant life, the dynamic behaviour of bearings subjected to typical …
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Ultrasonic acoustic health monitoring of ball bearings using neural network pattern classification of power spectral density
… the operating condition of conventional ball bearings. The acoustic emission signals used in this study are in the ultrasonic range (20-120 kHz), which is significantly higher than the majority of the research in this area thus far. A direct benefit of working in this frequency range is …
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A study of the effect of frequency, amplitude, and load on fretting corrosion of instrument ball bearings
Small precision ball bearings were vibrated for eight hour periods and coastdown was measured before and after vibration to determine fretting corrosion damage to the bearings. The load, frequency of vibration, and amplitude of vibration were each varied to determine their effects on the fretting …
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Prediction of the running torque of instrument ball bearings at high speed under combined radial and axial loads
… the torque versus speed behavior of instrument ball bearings between 1000 and 40,000 rpm with various combinations of radial and axial load ranging between 0 and 200 grams. Because of the lack of experimental data for instrument bearings over any range of speeds, loads and sizes, it was …
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The measurement of the running torque of oil and grease lubricated instrument ball bearings under combined radial and axial loads
… on the operating characteristics of instrument bearings, most were conducted at two rpm or less and with thrust load only. A study by H.H. Mable tested the running torques of radially loaded bearings from 1,000 to 40,000 rpm. The purpose of this investigation was to study the running torques of …
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The vibration of instrument ball bearings in a controlled environment and the effect of the resulting fretting corrosion on bearing torque
… between two flat specimens or between a single ball and a flat plate held in contact by a normal force. There are a number of interrelated influencing factors involved in fretting corrosion including: the vibration frequency and amplitude, the environmental conditions, the characteristics of the …
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The Response of a Structural Target to an Explosive Charge Incorporating Foreign Objects: A Numerical Study
… structure. The explosive, the container and the ball bearings were simplified representation of the key components of an improvised explosive device (IED). The numerical study was aimed at studying the ball bearing interaction with blast when incorporated into charge, and was based on previous …
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The response of a structural target to oblique fragment and blast loading
… to nails, pieces of glass, nuts, bolts and ball bearings [2]. Fragments, released upon the detonation of the device, are propelled outwards at high velocities and different directions with devastating effects on structures or human lives. Investigating the fragment effect is vital to develop …
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A study on the response of a target plate to a foreign object placed at various depths in a cylindrical Charge
… that consist of readily available items, such as ball bearings, nails or glass. The versatile nature of IEDs makes it very difficult to conduct a generalised study on their impact. One major challenge in IED research is the wide range of potential IED geometries, sizes, explosion types and …
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Numerical Modelling of Ball Bearing Stiffness to Predict Contact Stress Caused by Vibration Induced Gapping
The ball bearings that form part of mechanisms in space applications are subjected to vibrations. The result of these vibrations is gapping between the rings of the bearing. This gap allows collisions of the ball with the races, which produce high contact stresses. These high stresses can cause …
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Exercise in artificial gravity
… We also added a sliding mattress with linear ball bearings on rails, so that the subject's body can move up and down while stepping. Design changes and exercise feasibility were validated by having subjects exercise during centrifugation at 23 rpm. We measured heart rate, blood pressure, …
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Floating head skin friction gage measurements in supersonic flows
… contain a floating head that is supported by ball bearings which allow it to move in any horizontal direction and restrain it from any vertical motion. The shearing force caused by the supersonic flow deflects the floating head parallel to the flow direction. Strain gages mounted across a …
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Designing a Wearable, Centimeter-Scale Generator Powered by Human Movement
… structural components outside of the mag- nets, ball bearings, and center shaft are fabricated from compliant materials to enhance user comfort and device durability. The system is characterized across a range of pouch pressures and wall supply flowrates where a flowrate of 10 liters per minute …
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Energy Dissipation and Entropy Generation During the Fatigue Degradation: Application to Health Monitoring of Composites
… detection method for detection of wear in thrust ball bearings coated with molybdenum disulphide (MoS2) is presented. It employs an energy feature obtained from time-frequency representation of the vibration signal. Extensive experimental studies are conducted to verify the efficacy of the …
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Complex Mechanical Properties of Steel
… is a very complex phenomenon especially in bearings due to the Hertzian contact which takes place. A model has been developed that is able to quantify the residual stress distribution, under the raceway of martensitic ball bearings, using the running conditions. It is evident that a …
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