scholarly journals Dynamical Modelling and Simulation of Spur Gears with Flank Pitch Error

2021 ◽  
Author(s):  
Lizhuang Tao ◽  
De Tian ◽  
Shize Tang ◽  
Xiaoxuan Wu ◽  
Bei Li
Keyword(s):  
Dynamic Models ◽  
Vibration Signal ◽  
Spur Gear ◽  
Transmission Model ◽  
Spur Gears ◽  
Meshing Stiffness ◽  
Pitch Error ◽  
Gear Fault ◽  
Tooth Flank ◽  
The Impact

Abstract Gearbox is commonly regarded as the most important power section of wind turbines which has been widely valued for its high malfunction rate. Gear fault researches mainly include wearing, pitting, spalling, breakage, falling off, etc, while little attention was paid to tooth Flank Pitch Error(FPE). Taking a single-stage parallel shaft spur gear as the research object, an 8-DOF gear transmission model and the FPE model were established in this paper and the gear’s time-varying meshing stiffness (TVMS) models with & without tooth FPE were obtained respectively, which the dynamic models with various tooth FPE values under different rotating speeds were simulated after. The simulation results showed that the TVMS mathematical model proposed in the paper under tooth FPE is practical at both low and high rotating speeds. Under the FPE model, side-bands are formed around each multiple of meshing frequency whose peaks are distributed by a fixed fault characteristic frequency ffp interval. The gearbox vibrates severely as the tooth FPE values and rotational speed grow. The peak value of the vibration signal is about 3 times that in case of fault-free state when the FPE value reaches 0.001rad, thus the impact of FPE on gearboxes cannot be neglected.

Features of Early Cracks in a Gear Based on a 16DOF Nonlinear Time-Varying Stiffness Dynamic Model

2009 ◽  
Author(s):  
Xiaojun Zhou ◽  
Yimin Shao ◽  
Ming J. Zuo
Keyword(s):  
Crack Growth ◽  
Dynamic Model ◽  
Digital Filter ◽  
Energy Method ◽  
Vibration Signal ◽  
Spur Gear ◽  
Time Varying ◽  
Meshing Stiffness ◽  
One Stage ◽  
The Relationship

A 16DOF nonlinear time-varying stiffness dynamic model of a one-stage spur gear system is studied when there is a crack growth on the pinion; the energy method is then used for calculating the meshing stiffness of the gear pairs. A Hybrid Digital Filter is used to detect the feature signal which is induced by the tooth crack when the vibration signal contains heavy noise. The relationship between the indicators and the growth of the crack is given.

A Mathematical-Numerical Model to Calculate Load Distribution, Contact Stiffness and Transmission Error in Involute Spur Gears

2009 ◽  
Author(s):  
Mehdi Mohammadpour ◽  
Iraj Mirzaee ◽  
Shahram Khalilarya
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Load Distribution ◽  
Contact Stiffness ◽  
Transmission Error ◽  
Spur Gear ◽  
Spur Gears ◽  
Meshing Stiffness ◽  
Definition Of ◽  
The Mathematical Model

This paper firstly presents a mathematical model in order to calculate the load distribution, single contact stiffness and meshing stiffness as well as transmission error. in this way, there is no need to use finite element like methods and also the calculation time is dramatically reduced. Presented method is based on definition of a statically undetermined problem that is formulated using energy method. Some assumptions considered to convert this problem to a statically determined problem and get the mathematical models. Then a numerical method is employed in order to solve the mathematical model using a double iteration flowchart to close the problem. This model is flexible to adapt for any modification in spur gear profile geometry. Finally, this model is verified using previous works that have been utilized finite element and experimental model.

scholarly journals Detection of gear defects using method of wavelet decomposition and cross-correlation - Experiment to develop a feasible detection method

2018 ◽  
Vol 159 ◽  
pp. 02028
Author(s):  
R. Lullus Lambang G Hidayat ◽  
Budi Santoso
Keyword(s):  
Wavelet Transforms ◽  
Wavelet Decomposition ◽  
Cross Correlation ◽  
Vibration Signal ◽  
Machine Component ◽  
Spur Gears ◽  
Rotating Shaft ◽  
Gear Mesh ◽  
Maintenance Program ◽  
Gear Fault

Detection of machine component failure is very important to be properly applied in a maintenance program in industries. The objective of this research is to detect gear fault using wavelet transforms. The vibration signal is acquired with accelerometer mounted at bearing houses of 2 parallel shafts with 2 spur gears (28 tooth). The gears are rotated at 1200 RPM and the spectrum is displayed. The spectrum cannot indicate gear mesh frequencies (GMF), because they are covered with frequencies such as natural and harmonic frequencies of rotating shaft. This research have developed a method to obtain GMF using wavelet decomposition and cross correlation. The results showed that with FFT applied to cross-correlation of wavelet detil components, spectrum of visible and distinctable GMF has been obtained.

Study of Transient Elastohydrodynamic Lubrication of Spur Gears under Impact Load

2011 ◽  
Vol 121-126 ◽  
pp. 3506-3509
Author(s):  
You Qiang Wang ◽  
Zhi Cheng He ◽  
Wei Su
Keyword(s):  
Film Thickness ◽  
Impact Load ◽  
Gear Tooth ◽  
Elastohydrodynamic Lubrication ◽  
Spur Gear ◽  
Time Varying ◽  
Spur Gears ◽  
Lubrication Film ◽  
The Impact ◽  
Contact Parameters

Spur gear contacts experience a number of time-varying contact parameters including the load, surface velocities, radii of curvature, and slide-to-roll ratio. It is very hard to obtain transient elastohydrodynamic lubrication (EHL) solution of spur gears. In this study, a transient EHL model of involute spur gear tooth contacts is proposed. A full transient EHL solution of involute spur gear under impact load is obtained by utilizing the multigrid technique. The influences of impact load on the EHL of spur gear are analyzed in the paper. The numerical results show that the approach impact load has strong transient influence on the oil film thickness and pressure distribution between contact zones. The impact load may lead to instantaneous lubrication film deterioration between contact teeth of involute spur gears.

Comparison of Vibration Signal Analysis Methods for Effective Gear Fault Detection

2014 ◽  
Vol 709 ◽  
pp. 456-459
Author(s):  
Woong Yong Lee ◽  
Dong Hyong Lee ◽  
Hae Young Ji
Keyword(s):  
Signal Analysis ◽  
High Speed ◽  
Vibration Signal ◽  
Spur Gear ◽  
High Speed Train ◽  
Crest Factor ◽  
Gear Fault ◽  
Specimen Test ◽  
Vibration Signal Analysis ◽  
Crack Condition

Reduction unit for high-speed train is an important component. However if faults of reduction unit occurred, the damages such as material and human damage have been caused. To prevent the damage, it is necessary to study reduction unit monitoring for high-speed train. We conducted spur gear specimen test which was crack, breakage and pitting tests and analyzed FFT, Sideband energy ratio (SER), RMS, crest factor, and kurtosis. There was not distinct difference between no-fault and pitting condition at RMS, crest factor and kurtosis. But SER increased depending on crack condition. In breakage test, all parameters had difference between no-fault and breakage condition.

An Experimental Study of Influence of Lubrication Methods on Efficiency and Contact Fatigue Life of Spur Gears

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
J. Moss ◽  
A. Kahraman ◽  
C. Wink
Keyword(s):  
Experimental Study ◽  
Power Loss ◽  
Contact Fatigue ◽  
Spur Gear ◽  
Spur Gears ◽  
Power Losses ◽  
Contact Fatigue Life ◽  
The Impact ◽  
Jet Velocities ◽  
Lubrication Conditions

An experimental investigation of spur gear behavior was conducted with the aim of quantifying the impact of lubrication methods and conditions on the power losses and contact fatigue lives. Variations of dip and jet-lubrication are defined, and these behaviors were observed as a function of the lubrication conditions. Both types of measurements were performed using the same type of back-to-back test machines and the same spur gear test articles such that their evaluations can be correlated. Power loss experiments were performed under both loaded and unloaded conditions to determine both load-independent (spin) and load-dependent (mechanical) losses. Sets of long-cycle contact fatigue experiments were performed under the same lubrication conditions to determine macropitting lives in a statistically meaningful manner. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. Contact fatigue lives from jet-lubricated tests are comparable to those under dip-lubricated conditions ones as long as jet velocities are sufficient.

An Experimental Study of Influence of Lubrication Methods on Efficiency and Contact Fatigue Life of Spur Gears

2017 ◽  
Author(s):  
J. Moss ◽  
A. Kahraman ◽  
C. Wink
Keyword(s):  
Power Loss ◽  
Contact Fatigue ◽  
Spur Gear ◽  
Test Machine ◽  
Spur Gears ◽  
Power Losses ◽  
Contact Fatigue Life ◽  
The Impact ◽  
Jet Velocities ◽  
Lubrication Conditions

An experimental investigation of spur gear behavior was conducted with the aim of quantifying the impact of lubrication methods and conditions on the power losses and contact fatigue lives. Variations of dip and jet-lubrication were defined and these behaviors were observed as a function of the lubrication conditions. All measurements were performed using the same back-to-back test machine and the same spur gear test articles such that all evaluations were correlated. Power loss experiments were performed under both loaded and unloaded conditions to determine both load-independent (spin) and load-dependent (mechanical) losses. Sets of long-cycle contact fatigue experiments were performed under the same lubrication conditions to determine macro-pitting lives in a statistically meaningful manner. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. Contact fatigue lives from jet-lubricated tests are comparable to those under dip-lubricated conditions ones as long as jet velocities are sufficient.

scholarly journals Spur Gear Fault Diagnosis Using a Multilayer Gated Recurrent Unit Approach With Vibration Signal

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 56880-56889 ◽  
Author(s):  
Ying Tao ◽  
Xiaodan Wang ◽  
Rene-Vinicio Sanchez ◽  
Shuai Yang ◽  
Yun Bai
Keyword(s):  
Fault Diagnosis ◽  
Vibration Signal ◽  
Spur Gear ◽  
Gear Fault ◽  
Gear Fault Diagnosis ◽  
Gated Recurrent Unit

Monetary policy and the effect of the transfer of oil prices to inflation

2020 ◽  
pp. 41-50
Author(s):  
Ph. S. Kartaev ◽  
I. D. Medvedev
Keyword(s):  
Monetary Policy ◽  
Inflation Targeting ◽  
Dynamic Models ◽  
Oil Prices ◽  
Oil Price ◽  
Oil Price Shocks ◽  
Negative Effects ◽  
Price Shocks ◽  
Policy Regime ◽  
The Impact

The paper examines the impact of oil price shocks on inflation, as well as the impact of the choice of the monetary policy regime on the strength of this influence. We used dynamic models on panel data for the countries of the world for the period from 2000 to 2017. It is shown that mainly the impact of changes in oil prices on inflation is carried out through the channel of exchange rate. The paper demonstrates the influence of the transition to inflation targeting on the nature of the relationship between oil price shocks and inflation. This effect is asymmetrical: during periods of rising oil prices, inflation targeting reduces the effect of the transfer of oil prices, limiting negative effects of shock. During periods of decline in oil prices, this monetary policy regime, in contrast, contributes to a stronger transfer, helping to reduce inflation.

scholarly journals Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ganna Rozhnova ◽  
Christiaan H. van Dorp ◽  
Patricia Bruijning-Verhagen ◽  
Martin C. J. Bootsma ◽  
Janneke H. H. M. van de Wijgert ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Additional Benefit ◽  
Transmission Model ◽  
Time Points ◽  
School Based ◽  
Admission Data ◽  
Age Structured ◽  
The Impact ◽  
Pandemic Wave

AbstractThe role of school-based contacts in the epidemiology of SARS-CoV-2 is incompletely understood. We use an age-structured transmission model fitted to age-specific seroprevalence and hospital admission data to assess the effects of school-based measures at different time points during the COVID-19 pandemic in the Netherlands. Our analyses suggest that the impact of measures reducing school-based contacts depends on the remaining opportunities to reduce non-school-based contacts. If opportunities to reduce the effective reproduction number (Re) with non-school-based measures are exhausted or undesired and Re is still close to 1, the additional benefit of school-based measures may be considerable, particularly among older school children. As two examples, we demonstrate that keeping schools closed after the summer holidays in 2020, in the absence of other measures, would not have prevented the second pandemic wave in autumn 2020 but closing schools in November 2020 could have reduced Re below 1, with unchanged non-school-based contacts.

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