Dynamic analysis of a helical gear reduction by experimental and numerical methods

2020 ◽  
Vol 68 (1) ◽  
pp. 48-58
Author(s):  
Chao Liu ◽  
Zongde Fang ◽  
Fang Guo ◽  
Long Xiang ◽  
Yabin Guan ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Fourth Order ◽  
Numerical Models ◽  
Helical Gear ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Gear Mesh

Presented in this study is investigation of dynamic behavior of a helical gear reduction by experimental and numerical methods. A closed-loop test rig is designed to measure vibrations of the example system, and the basic principle as well as relevant signal processing method is introduced. A hybrid user-defined element model is established to predict relative vibration acceleration at the gear mesh in a direction normal to contact surfaces. The other two numerical models are also constructed by lumped mass method and contact FEM to compare with the previous model in terms of dynamic responses of the system. First, the experiment data demonstrate that the loaded transmission error calculated by LTCA method is generally acceptable and that the assumption ignoring the tooth backlash is valid under the conditions of large loads. Second, under the common operating conditions, the system vibrations obtained by the experimental and numerical methods primarily occur at the first fourth-order meshing frequencies and that the maximum vibration amplitude, for each method, appears on the fourth-order meshing frequency. Moreover, root-mean-square (RMS) value of the acceleration increases with the increasing loads. Finally, according to the comparison of the simulation results, the variation tendencies of the RMS value along with input rotational speed agree well and that the frequencies where the resonances occur keep coincident generally. With summaries of merit and demerit, application of each numerical method is suggested for dynamic analysis of cylindrical gear system, which aids designers for desirable dynamic behavior of the system and better solutions to engineering problems.

Combining Physics-Based and Data-Driven Models for Estimation of WOB During Ultra-Deep Ocean Drilling

2018 ◽  
Author(s):  
Tatsuya Kaneko ◽  
Ryota Wada ◽  
Masahiko Ozaki ◽  
Tomoya Inoue
Keyword(s):  
Hybrid Model ◽  
Numerical Models ◽  
Drill String ◽  
Operating Conditions ◽  
Data Driven ◽  
High Frequency Oscillation ◽  
Lumped Mass ◽  
Unknown Parameters ◽  
Mass Model ◽  
Time Operation

Offshore drilling with drill string over 10,000m long has many technical challenges. Among them, the challenge to control the weight on bit (WOB) between a certain range is inevitable for the integrity of drill pipes and the efficiency of the drilling operation. Since WOB cannot be monitored directly during drilling, the tension at the top of the drill string is used as an indicator of the WOB. However, WOB and the surface measured tension are known to show different features. The deviation among the two is due to the dynamic longitudinal behavior of the drill string, which becomes stronger as the drill string gets longer and more elastic. One feature of the difference is related to the occurrence of high-frequency oscillation. We have analyzed the longitudinal behavior of drill string with lumped-mass model and captured the descriptive behavior of such phenomena. However, such physics-based models are not sufficient for real-time operation. There are many unknown parameters that need to be tuned to fit the actual operating conditions. In addition, the huge and complex drilling system will have non-linear behavior, especially near the drilling annulus. These features will only be captured in the data obtained during operation. The proposed hybrid model is a combination of physics-based models and data-driven models. The basic idea is to utilize data-driven techniques to integrate the obtained data during operation into the physics-based model. There are many options on how far we integrate the data-driven techniques to the physics-based model. For example, we have been successful in estimating the WOB from the surface measured tension and the displacement of the drill string top with only recurrent neural networks (RNNs), provided we have enough data of WOB. Lack of WOB measurement cannot be avoided, so the amount of data needs to be increased by utilizing results from physics-based numerical models. The aim of the research is to find a good combination of the two models. In this paper, we will discuss several hybrid model configurations and its performance.

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.

Nonlinear Dynamic Analysis of a Flexible Rotor Supported by Externally Pressurized Porous Gas Journal Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 553-561 ◽  
Author(s):  
Cheng-Chi Wang ◽  
Cheng-Ying Lo ◽  
Cha’o-Kuang Chen
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Power Spectra ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Flexible Rotor ◽  
Bearing Number ◽  
Rotor Mass

This paper studies the nonlinear dynamic analysis of a flexible rotor supported by externally pressurized porous gas journal bearings. A time-dependent mathematical model for externally pressurized porous gas journal bearings is presented. The finite difference method and the Successive Over Relation (S.O.R.) method are employed to solve the modified Reynolds’ equation. The system state trajectory, Poincare´ maps, power spectra, and bifurcation diagrams are used to analyze the dynamic behavior of the rotor and journal center in the horizontal and vertical directions under different operating conditions. The analysis reveals a complex dynamic behavior comprising periodic and quasi-periodic response of the rotor and journal center. This paper shows how the dynamic behavior of this type of system varies with changes in rotor mass and bearing number. The results of this study contribute to a further understanding of the nonlinear dynamics of gas-lubricated, externally pressurized, porous rotor-bearing systems.

Prediction of Automotive Gearboxes Dynamic Behavior: Part A — Experimental Validation of a Global Numerical Model

2000 ◽  
Author(s):  
Karim Yakhou ◽  
Adeline Bourdon ◽  
Daniel Play
Keyword(s):  
Dynamic Behavior ◽  
Experimental Validation ◽  
Numerical Models ◽  
A Priori ◽  
Transmission Error ◽  
Operating Conditions ◽  
Step Procedure ◽  
Validation Procedure ◽  
Static Transmission Error

Abstract Numerical models have been developed to simulate the overall dynamic behavior of automotive gearboxes. They are based upon Finite Element Methods and their main originality is to integrate all the couplings between the various mechanical components of the gearboxes. The purpose of this study is to qualify these numerical models, and then, use them in order to determine gearboxes new design trends. In this first part of two companion papers, an experimental validation procedure has been implemented in two main stages. The first one is devoted to the study of mechanical systems under load but not-rotating. It is organized according to a “step by step” procedure. Starting with the shafts, the other components are gradually mounted and integrated into the mechanical system being considered. Thus, the modeling of the various parts has been validated and the existence of significant couplings has been confirmed. In the second stage of the procedure, the whole gearbox is studied under operating conditions. Preliminary tests at low rotational speeds allow the determination of the quasi-static transmission error under load. The results are used as input data for numerical simulations. Then tests are conducted at higher speeds with various resistant torques. Dynamic transmission error and dynamic loads transmitted by bearings are recorded. A good correlation between experiments and computations ensures the validity of the main a-priori modeling assumptions.

An Analytical and Experimental Study of the Dynamic Behavior of a Quick-Acting Hydraulic Fuse

1989 ◽  
Vol 111 (3) ◽  
pp. 528-534 ◽  
Author(s):  
S. R. Lee ◽  
K. Srinivasan
Keyword(s):  
Experimental Study ◽  
Response Time ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Dynamic Models ◽  
Operating Conditions ◽  
Experimental Setup ◽  
Hydraulic Circuit ◽  
Short Response Time ◽  
Good Agreement

The dynamic behavior of a quick-acting hydraulic fuse is investigated here by analysis and experiment. The fuse has a very short response time and is designed to respond to pressure and flow transients that immediately follow a line rupture. In view of the short response time, a proper dynamic analysis of the entire hydraulic circuit is necessary, in addition to analysis of the fuse behavior. Dynamic models of the fuse and other hydraulic circuit elements used in the experimental setup are presented. The experiments consist of simulating line leaks and measuring fuse response, under a variety of operating conditions. Experimental and analytical results are in very good agreement if the leak transients are properly characterized.

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.

scholarly journals Effective numerical methods to model dynamic behavior of springs with torsion

2018 ◽  
Author(s):  
◽  
E. Dilan Fernando
Keyword(s):  
Numerical Methods ◽  
Differential Equations ◽  
Numerical Method ◽  
Dynamic Behavior ◽  
Numerical Models ◽  
Software Implementation ◽  
Computer Language ◽  
Newtonian Mechanics ◽  
Systems Of Differential Equations ◽  
Kirchhoff Problem

The purpose of this thesis is to find effective algorithms to numerically solve certain systems of differential equations that arise from standard Newtonian mechanics. Numerical models of elastica has already been well studied. In this thesis we concentrate on the Kirchhoff problem. The goal is to create an effective and robust numerical method to model the dynamic behavior of springs that have a prescribed natural curvature. In addition to the mathematics, we also provide the implementation details of the numerical method using the computer language Python 3. We also discuss in detail the various difficulties of such a software implementation and how certain auxiliary computations can make the software more effective and robust.

Dynamic Analysis of a Historical Fortified Tower

2014 ◽  
Vol 628 ◽  
pp. 178-184 ◽  
Author(s):  
Mariella Diaferio
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Wide Class ◽  
Numerical Models ◽  
Structural Behavior ◽  
Static And Dynamic Analysis ◽  
Preliminary Results ◽  
Masonry Towers ◽  
The North ◽  
Seismic Forces

The present paper is centered on the static and dynamic analysis of the fortified tower of San Felice sul Panaro (Italy) citadel. The examined tower, that dated back to the XIV century, is particularly vulnerable to seismic forces, as the recent Emilia Romagna earthquake (2012) has demonstrated, and can be considered representative of a wide class of masonry towers located in the north of Italy. In order to evaluate the structural behavior, detailed numerical models of the tower with different level of complexity have been defined. In particular, the present paper shows the preliminary results of the static and dynamic analysis performed on such models and the influence of some parameters on the tower dynamic behavior.

Prediction of Automotive Gearboxes Dynamic Behavior: Part B — Numerical Simulations for the Determination of New Mechanical Design Trends

2000 ◽  
Author(s):  
Adeline Bourdon ◽  
Karim Yakhou ◽  
Daniel Play
Keyword(s):  
Dynamic Behavior ◽  
Mechanical Design ◽  
Numerical Models ◽  
Transmission Error ◽  
Design And Optimization ◽  
Gear Mesh ◽  
Dynamic Transmission Error ◽  
Design Activities ◽  
Market Pressures

Abstract Prediction of automotive gearboxes dynamic behavior during design is made possible through the use of numerical models and virtual prototypes. But market pressures require a formalization of new mechanical design activities. The aim of the second part of these two companion papers is to exploit the results to highlight future trends in mechanical design. Simulations performed with numerical models enable us to obtain a better understanding of the vibratory phenomena which appear in gearboxes. These models dissociate local effects, such as gear mesh phenomena, from “global” effects, due to the gearbox architecture and allow us to evaluate interactions between components. They are used for explaining some experimental observations, such as the large differences between the dynamic transmission error in “pullup position” — corresponding to an established speed or to an acceleration phase — and “pulldown position” — corresponding to a decreasing speed phase. Local gear mesh effects can not explain these large differences. They are also used for evaluating the influences of mechanical modifications to the bearing environment, on the dynamic transmission error. Then, the consequences of these results are applied to the design and optimization of new gearboxes.

A Transient Mixed Elastohydrodynamic Lubrication Model for Helical Gear Contacts

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
A. S. Chimanpure ◽  
A. Kahraman ◽  
D. Talbot
Keyword(s):  
Power Loss ◽  
Contact Region ◽  
Elastohydrodynamic Lubrication ◽  
Sensitivity Study ◽  
Helical Gear ◽  
Operating Conditions ◽  
Mechanical Power ◽  
Distribution Model ◽  
Rolling Velocity ◽  
Gear Mesh

Abstract In this study, a non-Newtonian, transient, isothermal, mixed elastohydrodynamic lubrication (EHL) model is proposed for helical gear contacts. The model accounts for nonelliptical contacts subject to spatially varying sliding and rolling velocity fields that are not aligned with any principal axis of the contact region, which is the case for helical gear contacts. The time-varying changes pertaining to key contact parameters and relative motion of roughness profiles on mating tooth surfaces are captured simultaneously to follow the contact from the root to the tip of a tooth while accounting for the transient effect due to relative motions of the roughness profiles. Actual tooth load distributions, contact kinematics, and compliances of helical gear contacts are provided to this model by an existing helical gear load distribution model. Measured three-dimensional roughness profiles covering the entire meshing zone are incorporated in the analyses to investigate its impact on the EHL conditions as well as mechanical power loss. Results of a parametric sensitivity study are presented to demonstrate the influence of operating conditions and surface roughness on the EHL behavior and the resultant gear mesh mechanical power loss of an example helical gear pair. The accuracy of the proposed mixed-EHL model is assessed by comparing the mechanical power loss predictions to available experimental results.

Sign in / Sign up

Export Citation Format

Share Document