Multilevel Optimization of the Geared Rotor-Bearing System for Multi-Objectives With Critical Speed Constraints

2004 ◽  
Author(s):  
T. N. Shiau ◽  
J. R. Chang ◽  
W. B. Lu
Keyword(s):  
Critical Speed ◽  
Transmission Error ◽  
Mesh Stiffness ◽  
Error Response ◽  
Critical Speeds ◽  
Gear Mesh ◽  
Unbalance Response ◽  
Multilevel Algorithm ◽  
Gear Mesh Stiffness ◽  
Bearing System

This paper presents the multi-objective optimization of a geared rotor-bearing system with the critical speeds constraints by using an efficient multilevel algorithm. The weight of each rotor shaft, the unbalance response, and the response due to the transmission error are minimized simultaneously under the critical speed constraints. The design variables are the inner radii of the shaft, the stiffness of bearings, and the gear mesh stiffness. The finite element method (FEM) is employed to analyze the dynamic characteristics and the method of feasible direction (MFD) is applied in the optimization of the single objective stage. Based on the sensitivity analysis that gear mesh stiffness has almost no influences on the critical speeds of the uncoupled modes of two shafts, an efficient multilevel algorithm composed of system and subsystem levels is developed. In the cycle of iteration, the minimization of the shaft weight is performed in the subsystem level with the critical speed constraints of only uncoupled modes of two shafts and the unbalance response and the transmission error response are reduced in the system level with the critical speed constraints of only coupled modes. It is indicated from the numerical results that the shaft weight, the unbalance response, and the transmission error response via the multilevel technique (ML) are all reduced much more than those via the weighting method (WM) and the goal programming method (GPM).

Dynamic analysis of a helical geared rotor-bearing system with composite rotating shafts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ying-Chung Chen ◽  
Xu Feng Cheng ◽  
Siu-Tong Choi
Keyword(s):  
Composite Material ◽  
Dynamic Analysis ◽  
Dynamic Characteristics ◽  
Mesh Stiffness ◽  
Content Type ◽  
Gear Mesh ◽  
Rotor Bearing ◽  
Rotating Shafts ◽  
Gear Mesh Stiffness ◽  
Bearing System

Purpose This study aims to study the dynamic characteristics of a helical geared rotor-bearing system with composite material rotating shafts. Design/methodology/approach A finite element model of a helical geared rotor-bearing system with composite material rotating shafts is developed, in which the rotating shafts of the system are composed of composite material and modeled as Timoshenko beam; a rigid mass is used to represent the gear and their gyroscopic effect is taken into account; bearings are modeled as linear spring-damper; and the equations of motion are obtained by applying Lagrange’s equation. Natural frequencies, mode description, lateral responses, axial responses, lamination angles, lamination numbers, gear mesh stiffness and bearing damping coefficients are investigated. Findings The desired mechanical properties could be constructed using different lamination numbers and fiber included angles by composite rotating shafts. The frequency of the lateral module decreases as the included angle of the fibers and the principal shaft of the composite material rotating shaft increase. Because of the gear mesh stiffness increase, the resonance frequency of the coupling module of the system decreases, the lateral module is not influenced and the steady-state response decreases. The amplitude of the steady-state lateral and axial responses gradually decreases as the bearing damping coefficient increases. Practical implications The model of a helical geared rotor-bearing system with composite material rotating shafts is established in this paper. The dynamic characteristics of a helical geared rotor-bearing system with composite rotating shafts are investigated. The numerical results of this study can be used as a reference for subsequent personnel research. Originality/value The dynamic characteristics of the geared rotor-bearing system had been reported in some literature. However, the dynamic analysis of a helical geared rotor-bearing system with composite material rotating shafts is still rarely investigated. This paper shows some novel results of lateral and axial response results obtained by different lamination angles and different lamination numbers. In the future, it makes valuable contributions for further development of dynamic analysis of a helical geared rotor-bearing system with composite material rotating shafts.

scholarly journals Geometry Modification of Helical Gear for Reduction of Static Transmission Error

2018 ◽  
Vol 167 ◽  
pp. 02013
Author(s):  
Jeonghyun Park ◽  
Changjun Seo ◽  
Kwangsuck Boo ◽  
Heungseob Kim
Keyword(s):  
Transmission Error ◽  
Helical Gear ◽  
Necessary Condition ◽  
Mesh Stiffness ◽  
Profile Modification ◽  
Gear Mesh ◽  
Static Transmission Error ◽  
Excitation Mechanisms ◽  
Gear Systems ◽  
Gear Mesh Stiffness

Gear systems are extensively employed in mechanical systems since they allow the transfer of power with a variety of gear ratios. So gears cause the inherent deflections and deformations due to the high pressure which occurs between the meshing teeth when transmit power and results in the transmission error. It is usually assumed that the transmission error and variation of the gear mesh stiffness are the dominant excitation mechanisms. Predicting the static transmission error is a necessary condition to reduce noise radiated from the gear systems. This paper aims to investigate the effect of tooth profile modifications on the transmission error of helical gear. The contact stress analysis was implemented for different roll positions to find out the most critical roll angle in view point of root flank stress. The PPTE (peak-to-peak of transmission error) is estimated at the roll angles by different loading conditions with two dimensional FEM. The optimal profile modification from the root to the tip is proposed.

Dynamic Analysis of a Spur Geared Rotor-Bearing System with Nonlinear Gear Mesh Stiffness

2014 ◽  
Vol 945-949 ◽  
pp. 853-861 ◽  
Author(s):  
Ying Chung Chen ◽  
Chung Hao Kang ◽  
Siu Tong Choi
Keyword(s):  
Dynamic Analysis ◽  
Equations Of Motion ◽  
Element Model ◽  
Dynamic Responses ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Lagrange’S Equation ◽  
Rotor Bearing ◽  
Gear Mesh Stiffness ◽  
Bearing System

The gear mesh stiffnesses have been regarded as constants in most previous models of geared rotor-bearing systems. In this paper, a dynamic analysis of a spur geared rotor-bearing system with nonlinear gear mesh stiffness is presented. The nonlinear gear mesh stiffness is accounted for by bending, fillet-foundation and contact deflections of gear teeth. A finite element model of the geared rotor-bearing system is developed, the equations of motion are obtained by applying Lagrange’s equation, and the dynamic responses are computed by using the fourth-order Runge-Kutta numerical method. Numerical results indicate that the proposed gear mesh stiffness provides a realistic dynamic response for spur geared rotor-bearing system.

Study on Helical Tooth Profile Modification of Planetary Gear Transmission on the Basis of Gear Transmission Error

2011 ◽  
Vol 86 ◽  
pp. 47-50
Author(s):  
Yu Tang ◽  
Shan Chang ◽  
Zhi Qiang Wang ◽  
Kun Zhang
Keyword(s):  
Planetary Gear ◽  
Transmission Error ◽  
Tooth Profile ◽  
Gear Transmission ◽  
Mesh Stiffness ◽  
Profile Modification ◽  
Gear Mesh ◽  
Tooth Profile Modification ◽  
Planetary Transmission ◽  
Gear Mesh Stiffness

In order to minimize the fluctuation of gear transmission error (GTE) about the planetary gear transmission. A method was developed to deciding tooth profile modification curves of planetary transmission. According to the condition of the invariable design load, computing the dynamic characteristics of the planetary transmission system under modified and un-modified gear. At the same time, the compare is carried through of the dynamic characteristics for modified and un-modified gear. The results of the dynamic calculation indicate that the profile modification method can make the amplitudes of gear mesh stiffness change calmness and reduce the amplitudes of gear mesh stiffness by this method in paper. At last, the conclusion can be obtained that the tooth profile modification can reduce the vibration and noise of the planetary transmission system.

An Analytical Investigation of Rattle Characteristics of Powder Metal Gears

2019 ◽  
Author(s):  
Elizabeth Slavkovsky ◽  
Murat Inalpolat ◽  
Anders Flodin
Keyword(s):  
Transmission Error ◽  
Analytical Investigation ◽  
Time Varying ◽  
Evaluation Tool ◽  
Mesh Stiffness ◽  
Gear Design ◽  
Gear Mesh ◽  
Internal Excitation ◽  
Gear Mesh Stiffness ◽  
Gear Rattle

Abstract This study employs an analytical model of a gear pair with transverse-torsional dynamics that allows analysis of single-sided, double-sided, and random rattle situations to contrast rattle characteristics of isotropic PM gears with a baseline steel gearset. This model utilizes time-varying gear mesh stiffness and transmission error as the internal excitation sources and time-varying operating torque as an external excitation. The gear rattle performance of PM gears is investigated under different torque conditions and operating speeds. The system kinetic and potential energy is assessed as an evaluation tool that can indicate the severity of different rattle conditions. The dynamic response of two different versions of an existing PM gear design are compared with a baseline traditional steel gear.

A parameterized numerical model for the evaluation of gear mesh stiffness variation of a helical gear pair

2008 ◽  
Vol 222 (7) ◽  
pp. 1321-1327 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Numerical Model ◽  
Transmission Error ◽  
Helical Gear ◽  
Hertzian Contact ◽  
Mesh Stiffness ◽  
Fe Method ◽  
Gear Design ◽  
Gear Mesh ◽  
Stiffness Variation ◽  
Gear Mesh Stiffness

One of the most common challenges in gear drive design is to determine the best combination of gear geometry parameters. These parameters should be capable of being varied effectively and related to gear mesh stiffness variation in advanced excitation and vibration analysis. Accurate prediction of gear mesh stiffness and transmission error requires an efficient numerical method. The parameterized numerical model was developed for the evaluation of excitation induced by mesh stiffness variation for helical gear design purposes. The model uses linear finite-element (FE) method to calculate tooth deflections, including tooth foundation flexibility. The model combines Hertzian contact analysis with structural analysis to avoid large FE meshes. Thus, mesh stiffness variation was obtained in the time and frequency domains, which gives flexibility if comparison is made with measured spectrums. Calculations showed that a fairly low number of elements suffice for the estimation of mesh stiffness variation. A reasonable compromise was achieved between design trends and calculation time.

Optimization Design of the Geared Rotor System With Critical Speed Constraints Using the Enhanced Genetic Algorithm

2008 ◽  
Author(s):  
T. N. Shiau ◽  
C. H. Kang ◽  
D. S. Liu ◽  
E. K. Lee ◽  
W. C. Hsu
Keyword(s):  
Genetic Algorithm ◽  
Optimization Design ◽  
Critical Speed ◽  
Hybrid Genetic Algorithm ◽  
Transmission Error ◽  
Rotor System ◽  
Gear Mesh ◽  
Design Variables ◽  
Bearing Stiffness ◽  
Gear Mesh Stiffness

This paper presents an efficient enhanced genetic algorithm to minimize the shaft weight, the unbalance response and the response due to the transmission error simultaneously. The minimization plays an important role in designing the geared rotor system under critical speed constraints. In the process of optimization, the design variables consist of shaft inner radii, bearing stiffness and the gear mesh stiffness. The enhanced genetic algorithm of optimization comprises the Hybrid Genetic Algorithm (HGA) and the Interval Genetic Algorithm (IGA). The HGA deals with this optimal design problem and the IGA accomplishes the interval optimization design. The results show that the presented enhanced genetic algorithm can not only effectively reduce the shaft weight and the transmission error response, but also precisely determine the interval ranges of design variables with feasible corresponding objective error.

Dynamic Analysis of a Geared Rotor-Bearing System with Time-Varying Gear Mesh Stiffness and Pressure Angle

2013 ◽  
Vol 284-287 ◽  
pp. 461-467
Author(s):  
Ying Chung Chen ◽  
Chung Hao Kang ◽  
Siu Tong Choi
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Responses ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Pressure Angle ◽  
Proposed Model ◽  
Rotor Bearing ◽  
Gear Mesh Stiffness ◽  
Bearing System

The dynamic analysis of a geared rotor-bearing system with time-varying gear mesh stiffness and pressure angle is presented in this paper. Although there are analyses for both of the gear and rotor-bearing system dynamics, the coupling effect of the time-varying mesh and geared rotor-bearing system is deficient. Therefore, the pressure angle and contact ratio of the geared rotor-bearing system are treated as time-varying variables in the proposed model while they were considered as constant in previous models. The gear mesh stiffness is varied with different contact ratios of the gear pair in the meshing process. The nonlinear equations of motion for the geared rotor-bearing system are obtained by applying Lagrange’s equation and the dynamic responses are computed by using the Runge-Kutta numerical method. Numerical results of this study indicated that the proposed model provides realistic dynamic response of a geared rotor-bearing system.

Dynamics of a Truck Gearbox

1992 ◽  
Author(s):  
J. Perret-Liaudet ◽  
J. Sabot
Keyword(s):  
Numerical Simulations ◽  
Dynamic Behaviour ◽  
Equations Of Motion ◽  
Transmission Error ◽  
Gear Transmission ◽  
The Finite Element Method ◽  
Mesh Stiffness ◽  
Gear Mesh ◽  
Static Transmission Error ◽  
Gear Mesh Stiffness

Abstract This work is concerned with numerous numerical simulations of the overall dynamic behaviour of a parallel helical gear transmission. These results are compared to vibratory measurements made with a simplified gearbox test rig. The dynamic modeling of the elastic components of the gear transmission (gears, shafts, bearings, housing) is realized using the finite element method. Fluctuated gear mesh stiffness is introduced owing to stiffness matrix which describes the elastic coupling between the pinion and the wheel. The kinematic transmission error is introduced as a vibratory excitation source. The equations of motion are established in a truncated modal base deduced from the average characteristics of the structure. A new computing method, called “Spectral Method”, is used for analytical study of a simplified gearbox whose housing is a simple rectangular plate. The numerical results allows us to conclude on the dominent phenomenon of the overall dynamic behaviour of the gear transmission. They exhibit in particular the main characteristics of the transfer between the static transmission error and the vibratory response of the gearbox. A series of vibration measurements made on a gearbox close to that used for the numerical simulations, has confirmed this characteristics.

A model for analyzing stiffness and stress in a helical gear pair with tooth profile errors

2016 ◽  
Vol 23 (2) ◽  
pp. 272-289 ◽  
Author(s):  
Qibin Wang ◽  
Yimin Zhang
Keyword(s):  
Contact Stress ◽  
Transmission Error ◽  
Helical Gear ◽  
Tooth Root ◽  
Mesh Stiffness ◽  
Tooth Contact ◽  
Gear Mesh ◽  
Profile Errors ◽  
Gear Mesh Stiffness ◽  
Root Stress

A model is introduced for analyzing the influence of tooth shape deviations and assembly errors on the helical gear mesh stiffness, loaded transmission error, tooth contact stress and tooth root stress. The helical gear is approximated as a series of independent spur gear slices along axial direction whose face-width is relatively small. The relative position relationships among those sliced teeth in mesh are developed with tooth profile errors and the stiffness of the sliced tooth is calculated by the potential energy method. From the equilibriums of the forces, gear mesh stiffness, loaded transmission error, tooth contact stress and tooth root stress are calculated. Then two cases are presented for validation of the model. It is demonstrated that the model is effective for calculating the stiffness of helical gear pairs. Finally, the effects of the tooth tip reliefs, lead crown reliefs and misalignments on the gear mesh stiffness, transmission error, tooth contact stress and tooth root stress are analyzed. The results show that mesh stiffness decreases, loaded transmission error, the maximum tooth contact stress and the maximum tooth root stress grow with the increasing tooth tip relief, lead crown relief and misalignment. And tooth edge has concentrated tooth contact stresses with a gear misalignment.

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