Nonlinear Dynamics of Multi-mesh Gear Systems PDF Download

Author: Gang Liu
Publisher:
ISBN:
Category : Gearing
Languages : en
Pages : 218

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Book Description
Abstract: Multi-mesh gear systems are used in a variety of industrial machinery, where noise, quality, and reliability lie in gear vibration. The dynamic gear mesh forces are the source of vibration and result from parametric excitation and contact nonlinearity. The primary goal of this work is to develop mathematical models for multi-mesh gearsets with nonlinear, time-varying elements, to conduct numerical and analytical studies on nonlinear gear dynamic behaviors, such as parametric instabilities, frequency response, contact loss, and profile modification, and to provide guidelines for practical design and troubleshooting. First, a nonlinear analytical model considering dynamic load distribution between individual gear teeth is proposed, including the influence of variable mesh stiffnesses, profile modifications, and contact loss. This model yields better agreement than two existing models when compared against nonlinear gear dynamics from a finite element benchmark. Perturbation analysis finds approximate frequency response solutions for providing guidance for optimizing system parameters. The closed-form solution is validated by numerical integration. Second, the nonlinear, parametrically excited dynamics of idler and counter-shaft gear systems are examined. The periodic steady state solutions are obtained using analytical and numerical approaches. With proper stipulations, the contact loss function and the variable mesh stiffness are reformulated into a form suitable for perturbation. The closed-form solutions from perturbation analysis expose the impact of key parameters on the nonlinear response. The analysis for this strongly nonlinear system compares well to separate harmonic balance/continuation and numerical integration solutions. Finally, this work studies the influences of tooth friction on parametric instabilities and dynamic response of a single-mesh gear pair. A mechanism whereby tooth friction causes gear tooth bending is shown to significantly impact the dynamic response. A dynamic model is developed to consider this mechanism together with the other contributions of tooth friction and mesh stiffness fluctuation. Perturbation analysis finds approximate solutions that predict and explain the parametric instabilities. The effects of time-varying friction moments about the gear centers and friction-induced tooth bending are critical to parametric instabilities and dynamic response. The impacts of friction coefficient, bending effect, contact ratio, and modal damping on the stability boundaries are revealed.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 30

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Modification of geometry of spur and helical gears with parallel axes and helical gears with crossed axes is proposed. The finishing process of gear generation is shaving. The purposes of modification of the gear geometry are to localize and stabilize the bearing contact, and to reduce noise and vibration. The goals mentioned above are achieved by using profile crowning and plunging the shaver by a prescribed motion during pinion generation. The pinion becomes double crowned. The gear member is generated as a conventional involute gear. A tooth contact analysis (TCA) program for simulation of meshing and contact was developed and the analysis is illustrated with TCA results for spur and helical gears.

Author: Gaetan Kerschen
Publisher: Springer
ISBN: 3319544047
Category : Technology & Engineering
Languages : en
Pages : 220

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Book Description
Nonlinear Dynamics, Volume 1: Proceedings of the 35th IMAC, A Conference and Exposition on Structural Dynamics, 2017, the first volume of ten from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Nonlinear Dynamics, including papers on: Nonlinear System Identification Nonlinear Modeling & Simulation Nonlinear Reduced-order Modeling Nonlinearity in Practice Nonlinearity in Aerospace Systems Nonlinearity in Multi-Physics Systems Nonlinear Modes and Modal Interactions Experimental Nonlinear Dynamics

Author: Steven James Martisauskas
Publisher:
ISBN:
Category : Dynamics
Languages : en
Pages : 546

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Book Description
Abstract: This thesis discusses a project to experimentally measure the dynamics of a multi- mesh gear system. Previous work on the design and testing of an idler gear system is detailed. Experimental results, specifically vibration modes of the test gearbox, correlate poorly with joint analytical modeling efforts. Limitations to the test setup, including high bearing drag and damping, result in questionable faith in experimental results. Disassembly of the test assembly results in anticipated damage to shaft and bearing components. Test gearbox components are repaired and modified, then re-assembled in a similar configuration. Results from testing on the newly modified gearbox are less limited by bearing drag and correlate well with previous results. The continued presence of high system damping leads to a critical analysis of modal extraction techniques. Agreement of experimental results between both assemblies of the test gearbox greatly increases faith in experimental results. Dynamic behavior including large amplitude parametric instabilities associated with mesh stiffness variation and nonlinear jump phenomena associated with tooth mesh contact loss are also experimentally demonstrated. Repeatability of this behavior is show to vary between various assemblies of the test gearbox.

Author: Herbert Ho-Ching Iu
Publisher: MDPI
ISBN: 3039211102
Category : Technology & Engineering
Languages : en
Pages : 435

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Book Description
The ever-increasing need for higher efficiency, smaller size, and lower cost make the analysis, understanding, and design of energy conversion systems extremely important, interesting, and even imperative. One of the most neglected features in the study of such systems is the effect of the inherent nonlinearities on the stability of the system. Due to these nonlinearities, these devices may exhibit undesirable and complex dynamics, which are the focus of many researchers. Even though a lot of research has taken place in this area during the last 20 years, it is still an active research topic for mainstream power engineers. This research has demonstrated that these systems can become unstable with a direct result in increased losses, extra subharmonics, and even uncontrollability/unobservability. The detailed study of these systems can help in the design of smaller, lighter, and less expensive converters that are particularly important in emerging areas of research like electric vehicles, smart grids, renewable energy sources, and others. The aim of this Special Issue is to cover control and nonlinear aspects of instabilities in different energy conversion systems: theoretical, analysis modelling, and practical solutions for such emerging applications. In this Special Issue, we present novel research works in different areas of the control and nonlinear dynamics of energy conversion systems.

Author: Matt Allen
Publisher: Springer
ISBN: 3319297635
Category : Technology & Engineering
Languages : en
Pages : 515

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Book Description
Dynamics of Coupled Structures, Volume 4. Proceedings of the 34th IMAC, A Conference and Exposition on Dynamics of Multiphysical Systems: From Active Materials to Vibroacoustics, 2016, the fourth volume of ten from the Conference brings together contributions to this important area of research and engineering. Th e collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: • Experimental Dynamic Substructuring • Structural Coupling of Nonlinear Structures • Analytical/Numerical Modeling of Joints • Industrial Applications of Substructuring • Source Identifi cation & Transfer Path Analysis • Human Induced Vibrations • Damping & Friction

Author: Junyi Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 176

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Book Description
This dissertation research focuses on evaluating the nonlinear dynamics of driveline systems employed in motor vehicles with emphasis on characterizing the excitations and response of right-angle, precision hypoid-type geared rotor structure. The main work and contribution of this dissertation is divided into three sections. Firstly, the development of an asymmetric and nonlinear gear mesh coupling model will be discussed. Secondly, the enhancement of the multi-term harmonic balance method (HBM) is presented. Thirdly and as the final topic, the development of new dynamic models capable of evaluating the dynamic coupling characteristics between the gear mesh and other driveline structures will be addressed. A new asymmetric and nonlinear mesh model will be proposed that considers backlash, and the fact that the tooth surfaces of the convex and concave sides are different. The proposed mesh model will then be fed into a dynamic model of the right-angle gear pair to formulate the dimensionless equation of motion of the dynamic model. The multi-term HBM will be enhanced to simulate the right-angle gear dynamics by solving the resultant dimensionless equation of motion. The accuracy of the enhanced HBM solution will be verified by comparison of its results to the more computationally intensive direct numerical integration calculations. The stability of both the primary and sub-harmonic solutions predicted by applying multi-term HBM will be analyzed using the Floquent Theory. In addition, the stability analysis of the multi-term HBM solutions will be proposed as an approximate approach for locating the existence of sub-harmonic and chaotic motions. In this dissertation research, a new methodology to evaluate the dynamic interaction between the nonlinear hypoid gear mesh mechanism and the time-varying characteristics of the rolling element bearings will also be developed. The time-varying mesh parameters will be obtained by synthesizing a 3-dimensional loaded tooth contact analysis (TCA) results. The time-varying stiffness matrix approach will be used to represent the dynamic characteristics of the rolling element bearings. An overall nonlinear dynamic model of the hypoid gear box considering elastic housing structure will be developed as well. A lumped parameter model of the flexible housing will be extracted form an appropriate set of frequency response functions through modal parameter identification method. In order to obtain the rotational coordinates, a rigid body interpolation of the translational responses at the bearing locations on the housing structure will be applied. The reduced model will be then coupled with the hypoid gear-shaft-bearing assembly model by applying a proposed dynamic coupling procedure. Finally, a hypoid geared rotor system model considering the propeller shaft flexibility will be established. The propeller shaft bending flexibility will be modeled as lumped parameter model through using the component mode synthesis (CMS). The torsional flexibility of propeller shaft will be simplified as a torsional spring connecting the inertia of moment of engine and pinion. Physically, the pinion input shaft is driven by the propeller shaft through a universal joint, which will be modeled as a flexible simple supported boundary condition as well as fluctuating rotation speed and torque excitation.

Author: Philippe Velex
Publisher: Chandos Publishing
ISBN: 1782421955
Category : Technology & Engineering
Languages : en
Pages : 1225

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Book Description
This book presents papers from the International Gear Conference 2014, held in Lyon, 26th-28th August 2014. Mechanical transmission components such as gears, rolling element bearings, CVTs, belts and chains are present in every industrial sector and over recent years, increasing competitive pressure and environmental concerns have provided an impetus for cleaner, more efficient and quieter units. Moreover, the emergence of relatively new applications such as wind turbines, hybrid transmissions and jet engines has led to even more severe constraints. The main objective of this conference is to provide a forum for the most recent advances, addressing the challenges in modern mechanical transmissions. The conference proceedings address all aspects of gear and power transmission technology and range of applications (aerospace, automotive, wind turbine, and others) including topical issues such as power losses and efficiency, gear vibrations and noise, lubrication, contact failures, tribo-dynamics and nano transmissions. A truly international contribution with more than 120 papers from all over the world A judicious balance between fundamental research and industrial concerns Participation of the most respected international experts in the field of gearing A wide range of applications in terms of size, power, speed, and industrial sector

Author: Jianrong Tan
Publisher: Springer
ISBN: 9811065535
Category : Technology & Engineering
Languages : en
Pages : 1667

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Book Description
Focusing on innovation, these proceedings present recent advances in the field of mechanical design in China and offer researchers, scholars and scientists an international platform to present their research findings and exchange their ideas. In the context of the “Made in China 2025” development strategy, one central aspect of the ICMD2017 was Innovative Design Pushes “Made in China 2025.” The book highlights research hotspots in mechanical design, such as design methodology, green design, robotics and mechanics, and reliability design, while also combining industrial design and mechanical design.

Author: Hao Zhang
Publisher: Springer Nature
ISBN: 3031261933
Category : Technology & Engineering
Languages : en
Pages : 1156

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Book Description
This volume gathers the latest advances, innovations and applications in the field of efficiency and performance engineering, as presented by leading international researchers and engineers at the 2022 conference of the Efficiency and Performance Engineering Network (TEPEN), held in Beijing and Baotou, China on August 18-21, 2022. Topics include vibro-acoustics monitoring, condition-based maintenance, sensing and instrumentation, machine health monitoring, maintenance auditing and organization, non-destructive testing, reliability, asset management, condition monitoring, life-cycle cost optimisation, prognostics and health management, maintenance performance measurement, manufacturing process monitoring, and robot-based monitoring and diagnostics. The contributions, which were selected through a rigorous international peer-review process, share exciting ideas that will spur novel research directions and foster new multidisciplinary collaborations.