Performance and Failure Modes of Grease Lubricated Hybrid Ceramic Bearing in High Speed and High Temperature Condition

2012 ◽  
Author(s):  
Dezhi Zheng ◽  
Le Gu ◽  
Tingjian Wang ◽  
Liqin Wang
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Failure Modes ◽  
Operating Conditions ◽  
Grease Lubrication ◽  
Operation Performance ◽  
Heavy Load ◽  
Ceramic Bearing ◽  
Rolling Element ◽  
Hybrid Silicon

Ceramic rolling element bearings have promising applications in extreme operating conditions such as high speed, high temperature, and heavy load. In this study, a hybrid silicon nitride ceramic ball bearing lubricated with high temperature grease is presented. The structure and parameters of the bearing are specially designed to satisfy the requirement of grease lubrication, high temperature and high speed conditions. A test rig was developed for the experiments of ceramic bearing performance. The experimental results show that grease lubricated ceramic bearings with fine design have excellent high speed and high temperature performance. By analyzing the operation performance and failure bearing inspection, the failure modes of grease lubricated ceramic bearings is analyzed. Thermal instability caused by the grease insufficient supply is the main factor of failure.

A Methodology for High Cycle Fatigue Characterization of Lead-Free Interconnects Under Simultaneous Harsh Environments of High Temperature and Vibration

2013 ◽  
Author(s):  
Pradeep Lall ◽  
Geeta Limaye
Keyword(s):  
High Temperature ◽  
High Speed ◽  
High Cycle Fatigue ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Natural Frequencies ◽  
Image Correlation ◽  
Lead Free ◽  
Cycle Fatigue ◽  
Increase With Increase

Current trends in the automotive industry warrant a variety of electronics for improved control, safety, efficiency and entertainment. Many of these electronic systems like engine control units, variable valve sensor, crankshaft-camshaft sensors are located under-hood. Electronics installed in under-hood applications are subjected simultaneously to mechanical vibrations and thermal loads. Typical failure modes caused by vibration induced high cycle fatigue include solder fatigue, copper trace or lead fracture. The solder interconnects accrue damage much faster when vibrated at elevated temperatures. Industry migration to lead-free solders has resulted in a proliferation of a wide variety of solder alloy compositions. Presently, the literature on mechanical behavior of lead-free alloys under simultaneous harsh environment of high-temperature vibration is sparse. In this paper, the reduction in stiffness of the PCB with temperature has been demonstrated by measuring the shift in natural frequencies. The test vehicle consisting of a variety of lead-free SAC305 daisy chain components including BGA, QFP, SOP and TSOPs has been tested to failure by subjecting it to two elevated temperatures and harmonic vibrations at the corresponding first natural frequency. The test matrix includes three test temperatures of 25C, 75C and 125C and simple harmonic vibration amplitude of 10G which are values typical in automotive testing. PCB deflection has been shown to increase with increase in temperature. The full field strain has been extracted using high speed cameras operating at 100,000 fps in conjunction with digital image correlation. Material properties of the PCB at test temperatures have been measured using tensile tests and dynamic mechanical analysis. FE simulation using global-local finite element models is thus correlated with the system characteristics such as modal shapes, natural frequencies and displacement amplitudes for every temperature. The solder level stresses have been extracted from the sub-models. Stress amplitude versus cycles to failure curves are obtained at all the three test temperatures. A comparison of failure modes for different surface mount packages at elevated test temperatures and vibration has been presented in this study.

scholarly journals Experimental Study on the Skidding Damage of a Cylindrical Roller Bearing

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4075 ◽  
Author(s):  
Qing Zhang ◽  
Jun Luo ◽  
Xiang-yu Xie ◽  
Jin Xu ◽  
Zhen-huan Ye
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Failure Modes ◽  
Roller Bearing ◽  
Weight Ratio ◽  
Operating Conditions ◽  
Roller Bearings ◽  
Light Load ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

As large-scale rotating machines develop toward high rotating speed and high power–weight ratio, skidding damage has become one of the major initial failure modes of cylindrical roller bearings. Therefore, understanding the skidding damage law is an effective way to ensure the safety of machines supported by cylindrical roller bearings. To realize the skidding damage, a high-speed rolling bearing test rig that can simulate the actual operating conditions of aviation bearings was used in this paper, and the skidding damage dynamic behaviors of cylindrical roller bearings were investigated. In addition, to ensure the accuracy of the obtained skidding damage mechanism, the cylindrical roller bearing was carefully inspected by microscopic analysis when the skidding damage occurred. Out results show that instantaneous increases in friction torque, vibration acceleration, and temperature are clearly observed when the skidding damage occurs in the cylindrical roller bearing. Furthermore, under the conditions of inadequate lubrication and light load, the critical speed of skidding damage is rather low. The major wear mechanisms of skidding damage include oxidation wear, abrasive wear, and delamination wear. The white layers are found locally in the inner ring and rollers under the actions of friction heat and shear force.

Nonlinear dynamic analysis of a microsegment gear system with a time-varying base circle

2020 ◽  
Vol 44 (2) ◽  
pp. 279-293
Author(s):  
Kang Huang ◽  
Fengwei Xu ◽  
Yangshou Xiong ◽  
Meng Sang ◽  
Yong Yi
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Operating Conditions ◽  
Gear System ◽  
Resonant Peak ◽  
Time Varying ◽  
Heavy Load ◽  
Involute Gear ◽  
Base Circle

A systematic dynamic analysis of a microsegment gear system with a time-varying base circle, time-varying mesh stiffness, and gear backlash is carried out in this paper. By discretizing the meshing process, a six degree-of-freedom nonlinear dynamic model of a microsegment gear pair is established. To study the dynamic response of the microsegment gear and involute gear under various operating conditions, the numerical integration method is adopted. The dynamic transmission error (DTE) of the two gears is analysed in terms of time history charts, phase diagrams, fast Fourier transformation spectra, and Poincaré maps. The effects of support damping and support stiffness on radial vibration are also investigated. Results reveal that, compared with the involute gear system, the microsegment gear system is more stable at the high-speed condition and has a smaller amplitude of DTE under medium-speed and heavy-load, high-speed, and heavy-load conditions. The support damping and support stiffness have great effects on the resonant peak in the radial direction of the microsegment gear. Both the proposed model and numerical results are expected to provide a useful source of reference for the dynamic design of the microsegment gear system.

Fundamental Design Issues of Brush Seals for Industrial Applications

2002 ◽  
Vol 124 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Saim Dinc ◽  
Mehmet Demiroglu ◽  
Norman Turnquist ◽  
Jason Mortzheim ◽  
Gayle Goetze ◽  
...  
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Design Parameters ◽  
Design Criteria ◽  
Seal Design ◽  
Brush Seal ◽  
Brush Seals ◽  
As Stress

Advanced seals have been applied to numerous turbine machines over the last decade to improve the performance and output. Industrial experiences have shown that significant benefits can be attained if the seals are designed and applied properly. On the other hand, penalties can be expected if brush seals are not designed correctly. In recent years, attempts have been made to apply brush seals to more challenging locations with high speed (>400 m/s), high temperature (>650 °C), and discontinuous contact surfaces, such as blade tips in a turbine. Various failure modes of a brush seal can be activated under these conditions. It becomes crucial to understand the physical behavior of a brush seal under the operating conditions, and to be capable of quantifying seal life and performance as functions of both operating parameters and seal design parameters. Design criteria are required for different failure modes such as stress, fatigue, creep, wear, oxidation etc. This paper illustrates some of the most important brush seal design criteria and the trade-off of different design approaches.

Heat Built-Up of Industrial Solid Tires in Thailand

2013 ◽  
Vol 844 ◽  
pp. 445-449
Author(s):  
Sanae Rukkur ◽  
Charoenyut Dechwayukul ◽  
Wiriya Thongruang ◽  
Orasa Patarapaiboolchai
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Heat Generation ◽  
Strain Energy ◽  
High Speed ◽  
Cyclic Load ◽  
Hysteresis Loops ◽  
Heavy Load ◽  
Heat Build Up ◽  
Temperature Work

Solid tires made of natural rubber, manufactured and used for forklift trucks in Thailand, have quality problems involving blow out [. Failure of solid tires may occur from excessive loads and or heat generation inducing loss of mechanical properties. The failure of solid tires relating to heat generation is considered. Solid tires under severe conditions, such as overloading, high speed, or high temperature work places often leading to fail and blowout. When these are continuously rolled and loaded, the rubber is stressed and deformed leading to heat generation [. The hysteresis loss storage in form of strain energy due to internal friction in the rubber converts to the heat source transfer to the section of tire. During carrying heavy load, solid tire is subjected to the repeat compressed cyclic loading. Since rubber has the visco-hyperelastic property, cyclic load deformation causes hysteresis loop when tire is performed under cyclic load. Hysteresis loops area indicates the amount of energy turn into heat and it is difficult transferring to the surface of the tire due to insulation itself. As the results, there is heat build-up as shown in term of temperature rising differs in each tire and finally causes blowout or explosion.

Exhaust Pressure Estimation and Its Application to Detection and Isolation of Turbocharger System Faults for Internal Combustion Engines

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Yue-Yun Wang ◽  
Ibrahim Haskara
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Failure Modes ◽  
Combustion Engine ◽  
Pressure Sensors ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
Recirculation Flow ◽  
Model Based

Engine exhaust backpressure is a critical parameter in the calculation of the volumetric efficiency and exhaust gas recirculation flow of an internal combustion engine. The backpressure also needs to be controlled to a presetting limit under high speed and load engine operating conditions to avoid damaging a turbocharger. In this paper, a method is developed to estimate exhaust pressure for internal combustion engines equipped with variable geometry turbochargers. The method uses a model-based approach that applies a coordinate transformation to generate a turbine map for the estimation of exhaust pressure. This estimation can substitute for an expensive pressure sensor, thus saving significant cost for production vehicles. On the other hand, for internal combustion engines that have already installed exhaust pressure sensors, this estimation can be used to generate residual signals for model-based diagnostics. Cumulative sum algorithms are applied to residuals based on multiple sensor fusion, and with the help of signal processing, the algorithms are able to detect and isolate critical failure modes of a turbocharger system.

Study on rheological properties of aviation lubricating oil under conditions of heavy load, high speed, and high temperature

2019 ◽  
Vol 71 (4) ◽  
pp. 525-531 ◽  
Author(s):  
Zhen Li ◽  
Xiaoli Zhao ◽  
Dezhi Zheng ◽  
Tingjian Wang ◽  
Le Gu ◽  
...  
Keyword(s):  
High Temperature ◽  
Rheological Properties ◽  
Rheological Model ◽  
High Speed ◽  
Traction Force ◽  
Lubricating Oil ◽  
Rheological Parameters ◽  
Heavy Load ◽  
Content Type ◽  
Loop Control

Purpose This study aims to evaluate the rheological properties of aviation lubricating oil under conditions of heavy load, high speed and high temperature and the applicability of the classical rheological model under severe conditions. Design/methodology/approach A Chinese aviation lubricating oil was used and its traction curves were obtained using a new two-disk tribotester. Its rheological parameters were calculated based on empirical formulae. Moreover, the traction force was calculated based on the classical Eyring rheological model. Findings The traction curves are obtained with respect to contact pressure, temperature and rolling speed. The rheological parameters are significantly influenced by environmental factors, especially viscosity. The traction force calculated using the Eyring model is consistent with the experimental results. Originality/value A novel two-disk tribotester was designed using a gas bearing and speed–force closed-loop control to ensure measurement accuracy. The mechanism of rheological properties was analyzed and the applicability of the classical rheological model under severe conditions was verified. It provided an experimental and theoretical basis for expanding the application of classical rheological models under extreme conditions.

Steady Characteristics of High-Speed Micro-Gas Journal Bearings With Different Gaseous Lubricants and Extreme Temperature Difference

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Xueqing Zhang ◽  
Qinghua Chen ◽  
Juanfang Liu
Keyword(s):  
High Temperature ◽  
Temperature Difference ◽  
Gas Turbines ◽  
High Speed ◽  
Load Capacity ◽  
Axial Direction ◽  
Operating Conditions ◽  
Thermal Creep ◽  
Large Temperature ◽  
The Stability

High-speed micro-gas journal bearing is one of the essential components of micro-gas turbines. As for the operating conditions of bearings, the high-speed, high-temperature, ultra-high temperature difference along the axial direction and the species of gaseous lubricants are extremely essential to be taken into account, and the effects of these factors are examined in this paper. The first-order modified Reynolds equation including the thermal creep, which results from the extremely large temperature gradient along the axial direction, is first derived and coupled with the simplified energy equation to investigate the steady hydrodynamic characteristics of the micro-gas bearings. Under the isothermal condition, it is found that CO2 can not only improve the stability of bearings but also generate a relatively higher load capacity by some comparisons. Thus, CO2 is chosen as the lubricant to further explore the influence of thermal creep. As the rotation speed and eccentricity ratio change, the thermal creep hardly has any effect on the gas film pressure. However, the shorter bearing length can augment the thermal creep. Compared with the cases without the thermal creep, the thermal creep could remarkably destroy the stability of gas bearing, but it might slightly enhance the load capacity.

Low-Friction Wear Resistant Coatings for High-Temperature Foil Bearings

2005 ◽  
Author(s):  
Hooshang Heshmat ◽  
Piotr Hryniewicz ◽  
James F. Walton ◽  
John P. Willis ◽  
Said Jahanmir
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Tribological Behavior ◽  
Operating Conditions ◽  
Hard Coatings ◽  
Wear Resistant Coatings ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Chrome Coating ◽  
Maximum Coefficient

Compliant foil bearings offer many advantages over rolling element bearings in high-speed and high-temperature applications. However, implementation of foil bearings in these applications requires development of solid lubricant coatings that can survive the severe operating conditions encountered at high speeds and high temperatures. The objective of this paper is to present results on development of an advanced coating system for use with compliant foil bearings that permits higher operating speeds and temperatures. In order to evaluate the coating performance and to select the best coating combination for implementation, a number tests were conducted using a high-temperature, high-speed tribometer up to 810 °C. Inconel test substrates, representative of a portion of a foil bearing, were coated with several different Korolon™ coatings. The counterface disks were coated with four different hard coatings. The test results confirmed the excellent tribological behavior of Korolon™ coatings for high-speed high-temperature foil bearing applications. While the tribological behavior of Korolon™ coatings were determined to be a function of temperature, in most cases a maximum coefficient of friction less than 0.1 was observed during startup/shutdown periods. Subsequently, a foil journal bearing was designed and a composite Korolon™ coating was applied to the bearing top foil; and a dense chrome coating was applied to the journal surface. The foil bearing was installed in a turbojet engine and operated successfully to 54,000 rpm for over 70 start-stop cycles.

High Temperature Supersonic Jet Facility for Aeroacoustic Studies

2001 ◽  
Author(s):  
Brenton J. Greska ◽  
Anjaneyulu Krothapalli
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Noise Suppression ◽  
Supersonic Jet ◽  
Infrared Camera ◽  
Operating Conditions ◽  
Laser Speckle ◽  
Stereoscopic Particle Image Velocimetry ◽  
Sudden Expansion ◽  
Jet Flows

Abstract This paper describes a newly built experimental facility at the Florida State University to develop innovative technologies for the noise suppression and mixing control of high-speed jets. This facility is capable of generating jet flows up to a maximum jet exit Mach number of about 2.5 at stagnation temperatures reaching up to 1500K. The facility can accommodate nozzles having an exit diameter of about 80 mm. At the maximum operating conditions, the jet can be run continuously for about 15 minutes. The jet exhausts into an anechoic room that measures 5.2 m (width) × 5.8 m (length) × 4 m (height). A sudden expansion (SUE) burner using Ethylene as its fuel is used to heat the high-pressure air. The instrumentation includes: High Resolution Infrared camera, stereoscopic Particle Image Velocimetry and Laser Speckle Displacement method for flow field measurements, high temperature unsteady pressure probes for the measurement of pressure fluctuations in the hydrodynamic field, and microphones with high speed data acquisition for far-field narrow band sound measurements.

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