WorldCat Identities

Townsend, Dennis P.

Overview
Works: 91 works in 207 publications in 2 languages and 4,158 library holdings
Genres: Handbooks and manuals 
Roles: Author, Editor, Other
Classifications: TJ184, 621.83
Publication Timeline
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Most widely held works by Dennis P Townsend
Dudley's gear handbook by Darle W Dudley( Book )

14 editions published between 1962 and 1992 in English and Spanish and held by 348 WorldCat member libraries worldwide

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 167 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 89 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
Dynamic loading of spur gears with linear or parabolic tooth profile modifications by Changyi Lin( Book )

3 editions published between 1988 and 1989 in English and held by 87 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)
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 86 WorldCat member libraries worldwide

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 86 WorldCat member libraries worldwide

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 86 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)
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 86 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
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 86 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 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 85 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
Helicopter transmission research at NASA Lewis Research Center by Dennis P Townsend( Book )

4 editions published between 1988 and 1997 in English and held by 85 WorldCat member libraries worldwide

This paper is a review of some of the research work of the NASA Lewis Research Center Mechanical Components Branch. It includes a brief review of the NASA Lewis Research Center and the Mechanical Components Branch. The research topics discussed are crack propagation of gear teeth, gear noise of spiral bevel and other gears, design optimization methods, methods we have investigated for transmission diagnostics, the analytical and experimental study of gear thermal conditions, the analytical and experimental study of split torque systems, the evaluation of several new advanced gear steels and transmission lubricants and the evaluation of various aircraft transmissions. The area of research needs for gearing and transmissions is also discussed
Optimum design of a gearbox for low vibration by Katsumi Inoue( Book )

2 editions published in 1992 in English and held by 85 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
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 84 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)
Profile modification to minimize spur gear dynamic loading by Changyi Lin( Book )

1 edition published in 1988 in English and held by 84 WorldCat member libraries worldwide

Minimization of the vibration energy of thin-plate structure by Katsumi Inoue( Book )

2 editions published in 1992 in English and held by 84 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
The surface fatigue life of contour induction hardened AISI 1552 gears by Dennis P Townsend( Book )

4 editions published in 1995 in English and held by 83 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)
Effect of advanced component technology on helicopter transmissions by David G Lewicki( Book )

3 editions published between 1987 and 1989 in English and held by 83 WorldCat member libraries worldwide

Experimental tests were performed on the NASA/Bell Helicopter Textron (BHT) 500-hp advanced technology transmission (ATT) at the NASA Lewis Research Center. The ATT was a retrofit of the OH-58C helicopter 236-kW (317-hp) main rotor transmission, upgraded to 373 kW (500 hp), with a design goal of retaining long life with a minimum increase in cost, weight, and size. Vibration, strain, efficiency, deflection, and temperature experiments were performed and the results were compared to previous experiments on the OH-58A, OH-58C, and UH-60A transmissions. The high-contact-ratio gears and the cantilever-mounted, flexible ring gear of the ATT reduced vibration compared to that of the OH-58C. The ATT flexible ring gear improved planetary load sharing compared to that of the rigid ring gear of the UH-60A transmission. The ATT mechanical efficiency was lower than that of the OH-58A transmission, probably due to the high-contact-ratio planetary gears. Keywords: Transmission; Gears; Bearings; Transmission testing; Efficiency; Vibration; Strain; Deflections; Helicopters; High-contact-ratio gears
Evaluation of CBS 600 carburized steel as a gear material by Dennis P Townsend( Book )

5 editions published between 1978 and 1979 in English and held by 78 WorldCat member libraries worldwide

Gearing by John J Coy( Book )

3 editions published in 1985 in English and held by 30 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)
Measurement of Gear Tooth Dynamic Friction( )

2 editions published in 1996 in English and held by 0 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
 
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Alternative Names
Townsend, D. P.

Townsend, D. P. (Dennis P.)

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