SIMPLIFIED APPROACH FOR THE DETERMINATION OF THE MECHANICAL EFFICIENCY IN GEAR TRAINS

2004 ◽  
Vol 40 (09) ◽  
pp. 33 ◽  
Author(s):  
Jiande Lin
Keyword(s):  
Mechanical Efficiency ◽  
Simplified Approach ◽  
Gear Trains

The Mechanical Efficiency of Epicyclic Gear Trains

1993 ◽  
Vol 115 (3) ◽  
pp. 645-651 ◽  
Author(s):  
E. Pennestri` ◽  
F. Freudenstein
Keyword(s):  
Mechanical Efficiency ◽  
Spur Gear ◽  
Efficiency Analysis ◽  
Gear Drive ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Gear Drives ◽  
General Computer Program ◽  
General Computer

The analysis of mechanical efficiency constitutes an important phase in the design analysis of gear drives. The objective of this investigation has been the development of a general algorithm for the determination of efficiency in split-power spur-gear trains. The model includes meshing losses only; for a more realistic estimation other sources can be considered separately. The systematic nature of the formulation, based on the dual correspondence between the kinematic structure of the gear drive and a labelled graph, allows a ready coding of the efficiency analysis in a general computer program. The numerical results are in line with those given by other authors using different methodologies.

Influence of Inlet Conditions on the Thermohydrodynamic State of a Fully Circumferentially Grooved Journal Bearing

2000 ◽  
Vol 123 (3) ◽  
pp. 525-532 ◽  
Author(s):  
P. S. Keogh ◽  
M. M. Khonsari
Keyword(s):  
Temperature Distribution ◽  
Energy Equation ◽  
Journal Bearing ◽  
Hydrodynamic Bearing ◽  
Simplified Approach ◽  
Supply Pressure ◽  
Axial Temperature ◽  
Viscosity Variation ◽  
Inlet Conditions

A thermohydrodynamic (THD) analysis of a fully circumferentially grooved hydrodynamic bearing is presented. The pressure distribution is obtained using the short bearing approximation taking into account the viscosity variation in the radial and circumferential coordinates. The axial temperature variation is also included by an axial averaging technique, which incorporates the supply pressure and film entry temperature in the energy equation. It is found that the determination of the lubricant temperature at the entry to the film plays an important role in the overall temperature distribution in the bearing. A simplified approach for determining this temperature is presented. An extensive set of experimental results performed by Maki and Ezzat (1980, ASME J. Lubr. Technol., 102, pp. 8–14) is used for validation purposes. The results show that mixing in the inlet groove may cause the film entry temperature to be significantly different from the nominal supply temperature and hence have a significant influence on the bearing temperature.

Simplified approach for determination of hepatic drug-oxidizing capacity using trimethadione metabolism as an indicator

1989 ◽  
Vol 10 (6) ◽  
pp. 617-620 ◽  
Author(s):  
Einosuke Tanaka ◽  
Shinichi Kobayashi ◽  
Koichi Nakamura ◽  
Eiji Uchida ◽  
Hajime Yasuhara
Keyword(s):  
Hepatic Drug ◽  
Simplified Approach

scholarly journals On a Simplified Model for Numerical Simulation of Wear During Dry Rolling Contacts

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
L. Chevalier ◽  
A. Eddhahak-Ouni ◽  
S. Cloupet
Keyword(s):  
Contact Area ◽  
Power Distribution ◽  
Contact Problems ◽  
Rolling Contact ◽  
Normal Loading ◽  
Fast Determination ◽  
Wear Process ◽  
Simplified Approach ◽  
Rolling Contacts

We deal with rolling contact between quasi-identical bodies. As normal and tangential problems are uncoupled in that case, the simplified approach to determine contact area and normal loading distribution for rolling contact problems is presented in Sec. 2. In Sec. 3, the solution of the tangential problem is used to update the rolling profiles and enables to follow the wear evolution versus time. The method used to solve the normal problem is called semi-Hertzian approach with diffusion. It allows fast determination of the contact area for non-Hertzian cases. The method is based on the geometrical indentation of bodies in contact: The contact area is found with correct dimensions but affected by some irregularities coming from the curvature’s discontinuity that may arise during a wear process. Diffusion between independent stripes smoothes the contact area and the pressure distribution. The tangential problem is also solved on each stripe of the contact area using an extension of the simplified approach developed by Kalker and called FASTSIM. At the end, this approach gives the dissipated power distribution in the contact during rolling and this power is related to wear by Archard’s law. This enables the profiles of the bodies to be updated and the evolution of the geometry to be followed.

A Framework for Efficiency Evaluation of Multi-Degree-of-Freedom Gear Trains

1996 ◽  
Vol 118 (4) ◽  
pp. 556-560 ◽  
Author(s):  
C. Innocenti
Keyword(s):  
Experimental Data ◽  
Finite Number ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Efficiency Evaluation ◽  
Suggested Approach ◽  
New Approach ◽  
Gear Trains ◽  
Two Degree Of Freedom

The paper proposes a new approach to the efficiency evaluation of any one- or multi-degree-of-freedom gear trains. The suggested approach generalizes the known procedures developed for two-degree-of-freedom gear trains. It is based on the determination of a vector whose components are the torques delivered to the shafts of the gear train. Furthermore the paper shows that, for a notable category of gear trains, such a vector can have only a finite number of directions, which implies that a limited number of experimental data suffices for estimating the efficiency at any operational condition. Examples of application of the proposed methodology are provided.

The Isocapnic Buffering Phase and Mechanical Efficiency: Relationship to Cycle Time Trial Performance of Short and Long Duration

2005 ◽  
Vol 30 (1) ◽  
pp. 46-60 ◽  
Author(s):  
David J. Bentley ◽  
Veronica E. Vleck ◽  
Gregoire P. Millet
Keyword(s):  
Power Output ◽  
Average Power ◽  
Time Trial ◽  
Mechanical Efficiency ◽  
Incremental Test ◽  
Long Duration ◽  
Average Power Output ◽  
And Performance ◽  
The Relationship

The purpose of this study was to determine the relationship between the isocapnic buffer (βisocapnic) and hypocapnic hyperventilation (HHV) phases as well as performance in a short (20-min) and long (90-min) time trial (TT) in trained athletes. In addition, gross (GE, %) and delta (ΔE, %) efficiency were calculated and the relationship between these variables and the average power output (W) in each TT was determined. Thirteen male endurance athletes (Mean ± SD age 31 ± 6 yrs; body mass 75.6 ± 6.3 kg; height 185 ± 6 cm) completed a continuous incremental test to exhaustion for determination of the βisocapnic and HHV phases. A second submaximal test was used to determine GE and ΔE. The average power output (W) was measured in a 20-min and 90-min cycling TT. The βisocapnic phase (W) was significantly correlated to the average power output (W) in the 20-min TT (r = 0.58; p <  0.05), but not in the 90-min TT (r = 0.28). The HHV phase (W) was not significantly correlated to the average power output in the 20-min or 90-min TT. No significant correlation was found for GE or for ΔE and performance in the TT. The data from this study shows that βisocapnic together with HHV is not likely to be a useful indicator of cycle TT performance of 20- to 90-min duration. Furthermore, GE and ΔE determined from a submaximal incremental stepwise test are not related to cycling TT performance of different duration. Key words: incremental, correlation, metabolism, athletes, fatigue

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