Prediction of Failure in Ductile Machine Elements Operating at Elevated Temperatures

1976 ◽  
Vol 98 (3) ◽  
pp. 1062-1065
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Elevated Temperatures ◽  
State Of The Art ◽  
Design Practice ◽  
Ductile Metals ◽  
Ductile Materials ◽  
Machine Element ◽  
Distortion Energy ◽  
Machine Elements ◽  
Sound Theoretical Basis ◽  
Good Agreement

This paper provides the designer with formulations and data so that he can more confidently design a ductile machine element, operating at elevated temperatures, by employing obtainable strength data at those temperatures. The paper begins by taking a panoramic view of the state of the art regarding a procedure for designing such elements, under such conditions, on the basis of stress vs. strength. Then, the paper combines the basic principle of the distortion-energy theory of failure, long recognized as the best theory of failure for ductile materials by well documented experiments, with thermodynamic behavioral and mechanical properties. This combination and accompanying study result in formulation, information and data so that the validity of the aforementioned design practice is given a sound theoretical basis. Specific applications are taken for various categories of steel with very good agreement between the theory and experimental data. However, with necessary data, the procedure can be applied to other ductile metals as well.

An Electrical Method for Failure Prediction in Ductile Machine Elements at Elevated Temperatures

1978 ◽  
Vol 100 (4) ◽  
pp. 614-618
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Electrical Resistivity ◽  
Critical Stress ◽  
Elevated Temperatures ◽  
Failure Prediction ◽  
Electrical Method ◽  
Conservation Of Energy ◽  
Ductile Metals ◽  
Machine Element ◽  
Machine Elements ◽  
Good Agreement

This paper provides the designer with an electrical method for failure prediction in ductile machine elements operating at elevated temperatures from room through the creep range. The law of conservation of energy, electrical considerations, and electrical properties are employed to result in a formulation. The formulation enables the designer to obtain, or verify, and then employ the critical stress value he requires in the design of a particular machine element operating at a given elevated temperature. It is shown that this critical stress value may be calculated simply by knowing the electrical resistivity value at the operating temperature, and the critical stress and electrical resistivity values at a datum (room) temperature. Specific applications are taken for various categories of steels with very good agreement between the theory and experimental data. The formulation is deemed to be applicable to other ductile metals as well.

Prediction of Yield in Ductile Materials Operating at Creep Temperatures

1977 ◽  
Vol 99 (3) ◽  
pp. 425-428
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Experimental Data ◽  
Elevated Temperature ◽  
Yield Strength ◽  
Yield Point ◽  
Room Temperature ◽  
Ductile Metals ◽  
Ductile Materials ◽  
Machine Element ◽  
Creep Temperature ◽  
Good Agreement

Utilizing a thermodynamic approach, this paper provides the designer with formulations and data so that he can obtain or verify, and then employ, the yield strength (or yield point) value he may desire in the design of a particular ductile machine element operating in the creep temperature range. A previous paper by the authors [1] dealt with the prediction of failure of such elements in the range between room temperature and the lower creep temperature. Thus, the present paper in conjunction with [1], and the references in both, is to provide a thermodynamic explanation for failure of such elements operating in elevated temperature environments ranging from room through creep temperatures. Specific applications are taken for three selected categories of steel with good agreement between the theory and experimental data. However, with necessary data, the procedures in this paper, as it was in [1], is expected to be applicable to other ductile metals as well.

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

scholarly journals Low adhesion effect of novel duplex NC/WC:C coatings against ductile materials at elevated temperatures

2018 ◽  
Vol 220 ◽  
pp. 32-35 ◽  
Author(s):  
Yangchun Dong ◽  
Kailun Zheng ◽  
Gonzalo Fuentes ◽  
Hanshan Dong
Keyword(s):  
Elevated Temperatures ◽  
Ductile Materials ◽  
Adhesion Effect

Blade Loading and Numerical Slip Factor of Centrifugal Compressor Impellers

1999 ◽  
Author(s):  
JongSik Oh
Keyword(s):  
State Of The Art ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Blade Design ◽  
Direct Relation ◽  
Blade Profile ◽  
Blade Loading ◽  
Slip Factor ◽  
Compressible Turbulent Flow ◽  
Good Agreement

Abstract Through the state-of-the-art CFD approach, the Eckardt radial bladed and backswept impellers were analyzed to investigate the effect of blade loadings from blade design shape on the slip factor variation for the change of the flow rate. In addition, a new design of the blade profile was arbitrarily attempted to generate a center-loading pattern in the Eckardt backswept impeller. Three dimensional compressible turbulent flow analysis was applied, with the Baldwin-Lomax turbulence model adopted, to get the numerical slip factor, using the mass-averaged concept, at the discharge plane of each impeller. The numerical slip factors are in good agreement with the experimental ones, and the Wiesner’s slip factors are found to deviate further from the numerical and experimental ones, especially in the two backswept impellers. The deviation angles and the blade loadings in the meridional channel are found in no direct relation with the trend of change of the slip factors. Blade-to-blade loadings in midspan location are, however, found in direct relation, especially at the sections where maximum loadings are to be expected. That information can be utilized in establishing an improved expression for slip factor in the future.

scholarly journals Classification and examples of next generation machine elements

2019 ◽  
Vol 84 (1) ◽  
pp. 21-32 ◽  
Author(s):  
G. Vorwerk-Handing ◽  
T. Gwosch ◽  
S. Schork ◽  
E. Kirchner ◽  
S. Matthiesen
Keyword(s):  
System Analysis ◽  
Signal Transmission ◽  
Main Research ◽  
Related Data ◽  
Research Areas ◽  
Machine Element ◽  
Machine Elements ◽  
Technical Systems ◽  
Key Aspects ◽  
Sensory Functions

Abstract In order to fully exploit the potential of the rapidly progressing digitalisation of technical systems, it is necessary to provide reliable and significant process and condition related data. In this context, solutions are especially aspired to allow a simple integration into the surrounding system and to influence it as little as possible. The main challenges regarding the measurement of process and condition data in the operation and control of technical systems as well as in test environments are identified and presented at the beginning of this article. A promising approach to meet the resulting requirements is the integration of sensory functions into simple standardised machine elements. In order to facilitate the discussion and interdisciplinary development of machine elements with sensory functions, an extension of the existing classification of mechatronic machine elements is introduced and illustrated with examples. The introduced classification takes into account the classification according to Stücheli and Meboldt and is based on a comparison of conventional and mechatronic machine elements on a functional level with regard to the function structure. As a result, the three classes sensor carrying machine elements, sensor integrating machine elements and sensory utilizable machine elements are introduced and subsequently discussed in more detail on the basis of examples. Finally, an outlook is given on the main research areas with regard to the development of mechatronic machine elements. Key aspects include working principles and effects for application in mechatronic machine elements, system analysis with regard to load conditions, power supply of sensor and data processor in the environment of the machine element as well as data processing and signal transmission under typical environmental conditions of mechanical engineering.

Influence of High-Temperature Bias Stress on Room-Temperature VT Drift Measurements in SiC Power MOSFETs

2019 ◽  
Vol 963 ◽  
pp. 757-762
Author(s):  
Daniel B. Habersat ◽  
Aivars Lelis ◽  
Ronald Green
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
State Of The Art ◽  
Charge Trapping ◽  
High Temperature Stress ◽  
Test Method ◽  
Power Mosfets ◽  
Temperature Bias ◽  
Bias Stress

Our results reinforce the notion of the need for an improved high-temperature gate bias (HTGB) test method — one which discourages the use of slow (greater than ~1 ms) threshold-voltage (VT) measurements at elevated temperatures and includes biased cool-down if room temperature measurements are performed, to ensure that any ephemeral effects during the high-temperature stress are observed. The paper presents a series of results on both state-of-the-art commercially-available devices as well as older vintage devices that exhibit enhanced charge-trapping effects. Although modern devices appear to be robust, it is important to ensure that any new devices released commercially, especially by new vendors, are properly evaluated for VT stability.

scholarly journals Comparison of Above-Water Seabird and TriOS Radiometers along an Atlantic Meridional Transect

2020 ◽  
Vol 12 (10) ◽  
pp. 1669
Author(s):  
Krista Alikas ◽  
Viktor Vabson ◽  
Ilmar Ansko ◽  
Gavin H. Tilstone ◽  
Giorgio Dall’Olmo ◽  
...  
Keyword(s):  
State Of The Art ◽  
Ocean Color ◽  
Percentage Difference ◽  
Wide Range ◽  
Before And After ◽  
Reference Measurements ◽  
Satellite Ocean Color ◽  
Good Agreement

The Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) project has carried out a range of activities to evaluate and improve the state-of-the-art in ocean color radiometry. This paper described the results from a ship-based intercomparison conducted on the Atlantic Meridional Transect 27 from 23rd September to 5th November 2017. Two different radiometric systems, TriOS-Radiation Measurement Sensor with Enhanced Spectral resolution (RAMSES) and Seabird-Hyperspectral Surface Acquisition System (HyperSAS), were compared and operated side-by-side over a wide range of Atlantic provinces and environmental conditions. Both systems were calibrated for traceability to SI (Système international) units at the same optical laboratory under uniform conditions before and after the field campaign. The in situ results and their accompanying uncertainties were evaluated using the same data handling protocols. The field data revealed variability in the responsivity between TRiOS and Seabird sensors, which is dependent on the ambient environmental and illumination conditions. The straylight effects for individual sensors were mostly within ±3%. A near infra-red (NIR) similarity correction changed the water-leaving reflectance (ρw) and water-leaving radiance (Lw) spectra significantly, bringing also a convergence in outliers. For improving the estimates of in situ uncertainty, it is recommended that additional characterization of radiometers and environmental ancillary measurements are undertaken. In general, the comparison of radiometric systems showed agreement within the evaluated uncertainty limits. Consistency of in situ results with the available Sentinel-3A Ocean and Land Color Instrument (OLCI) data in the range from (400…560) nm was also satisfactory (−8% < Mean Percentage Difference (MPD) < 15%) and showed good agreement in terms of the shape of the spectra and absolute values.

Heat Dissipation and Temperature Distribution of Brake Liner Using Steady State Analysis

2012 ◽  
Vol 249-250 ◽  
pp. 712-717
Author(s):  
M.P. Natarajan ◽  
B. Rajmohan
Keyword(s):  
Heat Dissipation ◽  
Friction Material ◽  
Automotive Application ◽  
Element Analysis ◽  
Slowing Down ◽  
Drum Brake ◽  
The Coefficient Of Friction ◽  
Machine Elements ◽  
Braking Process ◽  
Good Agreement

Brakes are machine elements that absorb kinetic energy in the process of slowing down or stopping a moving part. Brake capacity depends upon the unit pressure between the braking surfaces, the coefficient of friction, and the ability of the brake to dissipate heat equivalent to the energy being absorbed. In braking system, drum brake is used mostly for automotive application. During the braking process, the forces and pressures in a drum brake are difficult to determine because of the manner in which the shoe contacts the drum. Finite Element analysis has been used to predict interface temperatures and heat flows and the results have been compared with experimental measurements made using fine thermocouples. Good agreement has been achieved, showing that the proportion of heat which flows into the friction material varies with time and temperature.

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