Author: B Tech Vinayak AgashePublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Computational Analysis of the Dynamic Response of planetary Gear Systems, (Tech, The Ohio State University, 1998), Gear Dynamics and Gear Noise Research Laboratory
Author: B Tech Vinayak AgasheComputational Analysis of the Dynamic Response of a Planetary Gear System
Author: Vinayak AgasheAnalytical/Computational Investigation of Planetary Gear Dynamics in Rotorcraft Transmissions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
This research is a comprehensive analytical and computational investigation of the dynamic response of planetary gears. In military helicopters, planetary gears are typically the last stage gear reduction whose output drives the main rotor. Their vibration is the dominant source of cabin noise. The project objectives are to: * Develop analysis tools and engineering knowledge to reduce helicopter transmission dynamics and increase their reliability. * Develop analytical, lumped-parameter models that capture the complex, nonlinear tooth mesh interactions typically observed in multi-body, multi-mesh planetary gears. * Validate analytical modeling with a unique finite element-contact mechanics formulation that captures the tooth mesh forces and contact mechanics with accuracy beyond that achievable with conventional finite element tools. * Examine helicopter planetary gear dynamic response under operating conditions with coordinated analytical and computational simulations. Validate findings with experiments through related ARO DURIP and NRTC/RITA sponsored projects. * Identify techniques to minimize planetary gear dynamics and the associated cabin noise with intelligent early design. * Interact continuously with Army Research Lab staff at NASA Glenn and Army helicopter contractors regarding the Army technical needs and the findings of the research. Transfer technology and simulation tools to these parties and other US industry.
Planetary Gear Dynamics in Military Helicopters
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 9
Book Description
This research is a comprehensive analytical and computational investigation of the dynamic response of planetary gears. In military helicopters, planetary gears are typically the last stage gear reduction whose output drives the main rotor. Their dynamics dominate the cabin noise. Furthermore, the frequency of the noise is in the range most audible by humans. With deeper understanding of planetary gear dynamics, the goals are to reduce the noise, vibration, and weight of helicopter planetary gears while simultaneously increasing their reliability. This project will also develop lumped-parameter and finite element analysis tools for planetary gears. These tools are notably lacking despite the importance of planetary gears in helicopters, cars, heavy machinery, marine vehicle and other applications. Planetary gears have received little prior research attention as most gear dynamics studies address the simpler case of a single pair of meshing gears. Thus, the potential for scientific advancement and near-term practical application of the results is excellent. The unique computational tool available for this effort makes the objectives particularly achievable.
VIBRATION AND NOISE REDUCTION IN PLANETARY GEAR TRAIN BY PHASING
Author: Ashutosh MokatePublisher: Anchor Academic Publishing
ISBN: 3960670184
Category : Technology & Engineering
Languages : en
Pages : 117
Book Description
Gears are essential parts of many precision power transmitting machines such as automobiles. The major functions of a gearbox are to transform speed and torque in a given ratio and to change the axis of rotation. Planetary gears yield several advantages over conventional parallel shaft gear systems: They produce high speed reductions in compact spaces, a greater load sharing, a higher torque to weight ratio, diminished bearing loads, and reduced noise and vibration. They are used in automobiles, helicopters, aircraft engines, heavy machinery, and a variety of other applications. Despite their advantages, the noise induced by the vibration of planetary gear systems remains a key concern. Planetary gears have received considerably less research attention than single mesh gear pairs. There is a particular scarcity of analysis of two planetary gear systems and their dynamic response. Hence, this book focuses on the study of two PGTs with different phasing (angular positions) while every individual set remains unchanged.
Modeling, Modal Properties, and Mesh Stiffness Variation Instabilities of Planetary Gears
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 128
Book Description
Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery, and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigensensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation, manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears. their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigensensitivities and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods.
Analytical Study on Compound Planetary Gear Dynamics
Author: Yichao GuoPublisher:
ISBN:
Category :
Languages : en
Pages : 245
Book Description
The back-side mesh stiffness variation is inspected in this work to address the needs for gear vibration models that consider the gear tooth contacts on the back side. The results reveal the inherent relationship between the back-side and drive-side mesh stiffnesses. The impact of backlash on the back-side mesh stiffness variation function is also quantified.
Author: Husni Wijaya
Author: Branden C. Roesti
Author: Jian Lin