WorldCat Identities

Townsend, Dennis P.

Overview
Works: 83 works in 178 publications in 2 languages and 3,657 library holdings
Genres: Handbooks, manuals, etc 
Roles: Editor
Classifications: TJ184, 621.83
Publication Timeline
Key
Publications about  Dennis P Townsend Publications about Dennis P Townsend
Publications by  Dennis P Townsend Publications by Dennis P Townsend
Most widely held works by Dennis P Townsend
Dudley's gear handbook ( Book )
10 editions published between 1962 and 1992 in English and Spanish and held by 348 WorldCat member libraries worldwide
Gearing by John J Coy ( )
3 editions published in 1985 in English and held by 192 WorldCat member libraries worldwide
Gearing technology in its modern form has a history of only 100 years. However, the earliest form of gearing can probably be traced back to fourth century B.C. Greece. This publication draws together current gear practice and integrates it with recent advances in the technology. The history of gearing is reviewed briefly in the 'Introduction.' Subsequent sections describe types of gearing and their geometry, processing, and manufacture. Both conventional and more recent methods of determining gear stress and deflections are considered. The subjects of life prediction and lubrication are additions to the literature, not having been treated before. New and more complete methods of power loss prediction as well as an optimum design of spur gear meshes are described. Conventional and new types of power transmission system are presented. (Author)
Surface pitting fatigue life of noninvolute, low-contact-ratio gears by Dennis P Townsend ( Book )
2 editions published in 1990 in English and held by 121 WorldCat member libraries worldwide
Spur gear endurance tests were conducted to investigate the surface pitting fatigue life of nonivolute gears with low numbers of teeth and low contact ratios for use in advanced applications. The results were compared with those a standard involute design with a low number of teeth. The gear pitch diameter was 8.89 cm (3.50 in.) with 12 teeth on both gear designs. Test conditions were an oil inlet temperature of 320 K an oil outlet temperature of 350 K a maximum Hertz stress of 1.49 Gpa (216 ksi), and a speed of 10,000 rpm. The following results were obtained: The noninvolute gear had a surface pitting fatigue life approximately 1.6 times that of the standard involute gear of a similar design. The surface pitting fatigue life of the 3.43-pitch AISI 8620 noninvolute gear was approximately equal to the surface pitting fatigues the same load but at a considerably high maximum Hertz stress
Evaluation of a vibration diagnostic system for the detection of spiral bevel gear pitting failures by Dennis P Townsend ( Book )
4 editions published in 1996 in English and held by 80 WorldCat member libraries worldwide
A vibration diagnostic system was used to detect spiral bevel gear surface pitting fatigue in a closed loop spiral bevel gear fatigue test rig. The diagnostic system consists of a personal computer with an analog to digital conversion board, a diagnostic system unit and software. The diagnostic system performs time synchronous averaging of the vibration signal and produces a vibration image of each tooth on any gear in a transmission. Several parameters were analyzed including gear stresswave and raw baseband vibration, kurtosis, peak ratios of several parameters etc. The system provides limits for the various parameters and gives a warning when the limits are exceeded. Three spiral bevel gear tests were monitored with this system. The results show that the system is effective at detecting spiral bevel gear tooth surface pitting damage and other anomalies in the test rig
Measurement of gear tooth dynamic friction by Brian Rebbechi ( Book )
4 editions published in 1996 in English and held by 79 WorldCat member libraries worldwide
Measurements of dynamic friction forces at the gear tooth contact were undertaken using strain gages at the root fillets of two successive teeth. Results are presented from two gear sets over a range of speeds and loads. The results demonstrate that the friction coefficient does not appear to be significantly influenced by the sliding reversal at the pitch point, and that the friction coefficient values found are in accord with those in general use. The friction coefficient was found to increase at low sliding speeds. This agrees with the results of disc machine testing
Surface fatigue life and failure characteristics of EX-53, CBS 1000M, and AISI 9310 gear materials by Dennis P Townsend ( Book )
3 editions published in 1985 in English and held by 77 WorldCat member libraries worldwide
Evaluation of a vibration diagnostic system for the detection of spur gear pitting failures by Dennis P Townsend ( Book )
3 editions published in 1993 in English and held by 77 WorldCat member libraries worldwide
A vibration diagnostic system was used to detect spur gear surface pitting fatigue in a closed-loop spur gear fatigue test rig. The diagnostic system, comprising a personal computer with an analog-to-digital conversion board, a diagnostic system unit, and software, uses time-synchronous averaging of the vibration signal to produce a vibration image of each tooth on any gear in a transmission. Several parameters were analyzed including gear pair stresswave and raw baseband vibration, kurtosis, peak ratios, and others. The system provides limits for the various parameters and gives a warning when the limits are exceeded. Several spur gear tests were conducted with this system and vibration data analyzed at 5-min. intervals. The results presented herein show that the system is fairly effective at detecting spur gear tooth surface fatigue pitting failures ... Bearings, Fatigue, Diagnostic gear
Dynamic loading of spur gears with linear or parabolic tooth profile modifications by Hsiang Hsi Lin ( Book )
3 editions published between 1988 and 1989 in English and held by 76 WorldCat member libraries worldwide
A computer simulation was conducted to investigate the effects of both linear and parabolic tooth profile modification on the dynamic response of low-contact-ratio spur gears. The effect of the total amount of modification and the length of the modification zone were studied at various loads and speeds to find the optimal profile modification for minimal dynamic loading. Design charts consisting of normalized maximum dynamic load curves were generated for gear systems operated at various loads and with different tooth profile modification. An optimum profile modification can be determined from these design charts to minimize the dynamic loads of spur gear systems. Keywords: Spur gears, Gear teeth, Gear noise, Gearboxes, Dynamic load, Profile modification, Transmission error, Gear design. (SDW)
Lubricant jet flow phenomena in spur and helical gears with modified addendums-- for radially directed individual jets by Lee S Akin ( Book )
3 editions published between 1988 and 1989 in English and held by 76 WorldCat member libraries worldwide
This paper develops the mathematical relations for the Virtual Kinematic Model as an improvement over the vectorial model developed earlier. The model solution described herein the most energy efficient means of cooling gears-that is, it requires the least pressure of pumping power to distribute the coolant on the tooth surface. Further, this nozzle orientation allows impingement to the root of the tooth if needed and provides the most cooling control when compared to into-mesh or out-of-mesh cooling. Keywords: Lubrication; Gears; Cooling; Oil jet flow; Gear Geometry; Mathematical models. (sdw)
Optimum design of a gearbox for low vibration by Katsumi Inoue ( Book )
2 editions published in 1992 in English and held by 76 WorldCat member libraries worldwide
A computer program was developed for designing a low vibration gearbox. The code is based on a finite element shell analysis method, a modal analysis method, and a structural optimization method. In the finite element analysis, a triangular shell element with 18 degrees-of-freedom is used. In the optimization method, the overall vibration energy of the gearbox is used as the objective function and is minimized at the exciting frequency by varying the finite element thickness. Modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variable. The sensitivity is representative of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight. The computer code is applied to a design problem derived from an experimental gearbox in use at the NASA lewis Research Center. The top plate and two side plates of the gearbox are redesigned and the contribution of each surface to the total vibration is determined. Results show that optimization of the top plate alone is effective in reducing total gearbox vibration
Minimization of the vibration energy of thin-plate structure by Katsumi Inoue ( Book )
2 editions published in 1992 in English and held by 76 WorldCat member libraries worldwide
An optimization method is proposed to reduce the vibration of thin-plate structures. The method is based on a finite-element shell analysis, a modal analysis, and a structural optimization method. In the finite-element analysis, a triangular shell element with 18 degrees of freedom is used. In the optimization, the overall vibration energy of the structure is adopted as the objective function, and it is minimized at the given exciting frequency by varying the thickness of the elements. The technique of modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variables. The sensitivity is represented by the sensitivities of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight. A computer code, based on the proposed method, is developed and is applied to design problems using a beam and a plate as test cases. It is confirmed that the vibration energy is reduced at the given exciting frequency. For the beam excited by a frequency slightly less than the fundamental natural frequency, the optimized shape is close to the beam of uniform strength. For the plate, the optimum shape is obtained such that the changes in thickness have the effect of adding a stiffener or a mass
Wear consideration in gear design for space applications by Lee S Akin ( Book )
3 editions published between 1988 and 1989 in English and held by 75 WorldCat member libraries worldwide
A procedure is described that was developed for evaluating the wear in a set of gears in mesh under high load and low rotational speed. The method can be used for only low-speed gear application, with nearly negligible oil film thickness, and is especially useful in space stepping mechanism applications where determination of pointing error due to wear is important, such as in long life sensor antenna drives. A method is developed for total wear depth at the ends of the line of action using a very simple formula with the slide to roll ratio Vs/Vr. A method is also developed that uses the wear results to calculate the transmission error also known as pointing error of a gear mesh. Gears used in space applications are usually thought of as instrument gears with negligible load that must maintain position accuracy throughout their operational life or as deployment/actuator gears that may have inertial loads but a very low number of duty cycles
Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars by Dennis P Townsend ( Book )
1 edition published in 1989 in English and held by 75 WorldCat member libraries worldwide
Surface fatigue life of high temperature gear materials by Dennis P Townsend ( Book )
2 editions published in 1994 in English and held by 75 WorldCat member libraries worldwide
Three high temperature gear materials were evaluated using spur gear surface fatigue tests. These materials were, VASCO max 350, VASCO matrix H, and nitralloy N and were evaluated for possible use in high temperature gear applications. The fatigue life of the three high temperature gear materials were compared with the life of the standard AISI 9310 aircraft gear material. Surface fatigue tests were conducted at a lubricant inlet temperature of 321 K (120 deg F), a lubricant outlet temperature of 350 K (170 deg F), a maximum Hertz stress of 1.71 GPa (248 ksi), a speed of 10000 rpm and with a synthetic paraffinic lubricant. The life of the nitralloy N was approximately the same as the MSI 9310, the life of the VASCO max 350 was much less than the AISI 9310 while the life of the VASCO matrix H was several times the life of the AISI 9310. The VASCO max 350 also showed very low fracture toughness with approximately half of the gears failed by tooth fracture through the fatigue spall. The VASCO matrix II had approximately 10-percent fracture failure through the fatigue spalls indicating moderate to good fracture toughness. (MM)
Improvement in surface fatigue life of hardened gears by high-intensity shot peening by Dennis P Townsend ( Book )
2 editions published in 1992 in English and held by 75 WorldCat member libraries worldwide
Two groups of carburized, hardened, and ground spur gears that were manufactured from the same heat of vacuum-induction-melted-vacuum-arc-remelted (VIM-VAR) AISI 9-310 steel were endurance tested for surface fatigue. Both groups were manufactured with a standard ground 16-rms surface finish. One group was subjected to a shot-peening intensity of 7 to 9A, and the second group was subjected to a shot-peening intensity of 15 to 17A. All gears were honed after shot peening to a surface finish of 16 rms. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a gear temperature of 350 K (170 deg F), and a speed of 10 000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The following results were obtained: The 10-percent surface fatigue (pitting) life of the high-intensity (15 to 17A) shot-peened gears was 2.15 times that of the medium-intensity (7 to 9A) shot-peened gears, the same as that calculated from measured residual stress at a depth of 127 microns (5 mil). The measured residual stress for the high-intensity-shot-peened gears was 57 percent higher than that for the medium-intensity-shot-peened gears at a depth of 127 micro (5 mi) and 540 percent higher at a depth of 51 micro (2 mil)
Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears by Dennis P Townsend ( Book )
4 editions published in 1988 in English and held by 75 WorldCat member libraries worldwide
Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Test were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground. Grinding of Carburized and Hardened Gear Teeth for aircraft application has been standard practice for many years. Grinding is required to produce the required accuracy and surface finish necessary for improved life, reduced noise and dynamic loads for aircraft gears. Until a few years ago, the method used for grinding hardened gears was the standard vitreous grinding wheels
The surface fatigue life of contour induction hardened AISI 1552 gears by Dennis P Townsend ( Book )
3 editions published in 1995 in English and held by 74 WorldCat member libraries worldwide
Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from MSI 1552 and was finished ground to a 0.4 um (16 um.) rms. surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 um (16 uin.) rms. surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 OPa (248 ksi), a bulk gear temperature of approximately 350 K (170F) and a speed of 10000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AlSI 1552 gears by bending fatigue. (MM)
Effects of lubrication on the performance of high speed spur gears by Hachiro Mizutani ( Book )
2 editions published in 1989 in English and held by 74 WorldCat member libraries worldwide
An experimental analysis was conducted to determine power loss and gear noise of high speed spur gears with long addendum under various conditions of load, speed, and jet oil pressure for into mesh lubrication. Power losses were calculated from temperature measurements of lubricating oil, gears, gear box, and oil flow rate. Furthermore, power loss was divided into windage loss, friction loss and churning loss. The results show that windage loss and churning loss were the main components of gear power loss of high gear speed. In addition, lubricating conditions had some influences on gear noise especially under low oil temperature or high viscosity
Dynamic measurements of gear tooth friction and load by Brian Rebbechi ( Book )
2 editions published in 1991 in English and held by 74 WorldCat member libraries worldwide
As part of a program to study fundamental mechanisms of gear noise, static and dynamic gear tooth strain measurements were made on the NASA gear- noise rig. Toothfillet strains from low contact ratio spur gears were recorded for 28 operating conditions. A method is introduced whereby strain gage measurements taken from both the tension and compression sides of a gear tooth can be transformed into the normal and frictional loads on the tooth. This technique was applied to both the static and dynamic strain data. The static case results showed close agreement with expected results. For the dynamic case, the normal-force computation produced very good results, but the friction results, although promising, were not as accurate. Tooth sliding friction strongly affected the signal from the strain gage on the tension side of the tooth. The compression gage was affected by friction to a much lesser degree. The potential of the method to measure friction force has been demonstrated, but further refinement will be required before this technique can be used to measure friction forces dynamically with an acceptable degree of accuracy
Surface fatigue life of M50NiL and AISI 9310 spur gears and R C bars by Dennis P Townsend ( Book )
2 editions published in 1991 in English and held by 74 WorldCat member libraries worldwide
Spur gear endurance tests and rolling-element surface fatigue tests were conducted to investigate vacuum-induction-melted, vacuum-arc-remelted (VIM- VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10 000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12 500 rpm and a maximum Hertz stress of 4.83 GPa (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR m50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  Kids General Special  
Audience level: 0.85 (from 0.63 for Dudley's g ... to 0.93 for Evaluation ...)
Alternative Names
Townsend, D. P. (Dennis P.)
Languages
English (59)
Spanish (1)