scholarly journals Investigation of the characteristics of the component of vibration of gas turbine engine gearbox that causes fatigue failures of its structural elements in case of tooth flank wear

2020 ◽  
Vol 19 (4) ◽  
pp. 70-79
Author(s):  
A. E. Sundukov
Keyword(s):  
Flank Wear ◽  
Gear Tooth ◽  
Technical Condition ◽  
Structural Elements ◽  
Turbine Engine ◽  
Steady State Operation ◽  
Turboprop Engine ◽  
Planet Gear ◽  
Tooth Flank ◽  
Fatigue Failures

The paper presents an analysis of the component of vibration of the NK-12MP turboprop engine differential gearbox that is generated by the wear of the flanks of the teeth of the sun gear planet gear assembly pair and at certain values of its intensity may cause fatigue breakdown of the engines structural elements. A complex of diagnostic indicators is determined on the basis of this component. Its intensity is shown to be maximal in steady-state operation of the engine with the greatest run time. The data obtained by the spectrum of maxima are shown to have higher information content as compared to the autospectrum data. The complex of diagnostic indicators proposed on the basis of the component under consideration makes it possible to successfully control the technical condition of the differential gearbox by the defects of gear tooth flank wear.

Surface fitting of an involute spur gear tooth flank roughness measurement to its nominal shape

Measurement ◽  
2016 ◽  
Vol 91 ◽  
pp. 479-487 ◽  
Author(s):  
José A. Brandão ◽  
Jorge H.O. Seabra ◽  
Manuel J.D. Castro
Keyword(s):  
Gear Tooth ◽  
Spur Gear ◽  
Surface Fitting ◽  
Roughness Measurement ◽  
Tooth Flank

scholarly journals Planetary Gearbox Dynamic Modeling Considering Bearing Clearance and Sun Gear Tooth Crack

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2638
Author(s):  
Xianhua Chen ◽  
Xingkai Yang ◽  
Ming J. Zuo ◽  
Zhigang Tian
Keyword(s):  
Dynamic Model ◽  
Dynamic Modeling ◽  
Failure Modes ◽  
Gear Tooth ◽  
Working Environment ◽  
The Sun ◽  
Planetary Gearbox ◽  
Bearing Clearance ◽  
Vibration Responses ◽  
Planet Gear

Planetary gearbox systems are critical mechanical components in heavy machinery such as wind turbines. They may suffer from various failure modes, due to the harsh working environment. Dynamic modeling is a useful method to support early fault detection for enhancing reliability and reducing maintenance costs. However, reported studies have not considered the sun gear tooth crack and bearing clearance simultaneously to analyze their combined effect on vibration characteristics of planetary gearboxes. In this paper, a dynamic model is developed for planetary gearboxes considering the clearance of planet gear, sun gear, and carrier bearings, as well as sun gear tooth crack levels. Bearing forces are calculated considering bearing clearance, and the dynamic model equations are updated accordingly. The results reveal that the combination of bearing clearances can affect the vibration response with sun gear tooth crack by increasing the kurtosis. It is found that the effect of planet gear bearing clearance is very small, while the sun gear and carrier bearing clearance has clear impact on the vibration responses. These findings suggest that the incorporation of bearing clearance is important for planetary gearbox dynamic modeling.

Generation of the Anti-Twist Crowned Helical Gear by Modifying the Gear Rotation Angle in the Hobbing Process

2017 ◽  
Vol 749 ◽  
pp. 161-170
Author(s):  
Ruei Hung Hsu ◽  
Yu Ren Wu ◽  
Shih Sheng Chen
Keyword(s):  
Rotation Angle ◽  
Gear Tooth ◽  
Helical Gear ◽  
Gear Hobbing ◽  
Tooth Flank ◽  
Center Distance

In the gear-hobbing process, the work gear tooth flank is usually longitudinally crowned by varying the center distance between the hob and the work gear. Without crossed angle compensation, however, this center distance variation produces a twisted tooth flank on the work gear. This paper therefore proposes a methodology to reduce this tooth flank twist and achieve anti-twist in longitudinal crowning by modifying the gear rotation angle in the hobbing process which is practiced using a CNC hobbing machine with three synchronous axes.

A parameterized numerical method for generating discrete helical gear tooth surface allowing non-standard geometry

2008 ◽  
Vol 222 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Gear Tooth ◽  
Numerical Approach ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tool Profile ◽  
Standard Geometry ◽  
Gear Manufacturing ◽  
Involute Gears ◽  
Gear Geometry ◽  
Tooth Flank

Gear analysis is typically performed using calculation based on gear standards. Standards provide a good basis in gear geometry calculation for involute gears, but these are unsatisfactory for handling geometry deviations such as tooth flank modifications. The efficient utilization of finite-element calculation also requires the geometry generation to be parameterized. A parameterized numerical approach was developed to create discrete helical gear geometry and contact line by simulating the gear manufacturing, i.e. the hobbing process. This method is based on coordinate transformations and a wide set of numerical calculation points and their synchronization, which permits deviations from common involute geometry. As an example, the model is applied to protuberance tool profile and grinding with tip relief. A fairly low number of calculation points are needed to create tooth flank profiles where error is <1 μm.

Probabilistic Analysis of Intermediate Floor Steel and Wooden Structures in the Old Urban Development Building

2014 ◽  
Vol 633-634 ◽  
pp. 1140-1147
Author(s):  
Vladimir Alekseevich Sokolov
Keyword(s):  
Information Theory ◽  
Urban Development ◽  
Probabilistic Analysis ◽  
Technical Condition ◽  
Probabilistic Methods ◽  
Technical Diagnostics ◽  
Structural Elements ◽  
Complex Technical Systems ◽  
Technical Systems ◽  
Wooden Structures

The article suggests an approach to determine structural elements technical condition, based on the mathematical probabilistic apparatus of technical diagnostics. Diagnostics are performed using probabilistic methods of complex technical systems conditions recognition. Probabilistic parameters are calculated according to Bayes’s rule. The paper shows a diagnostics example of intermediate floor elements and systems in the old urban development building. Both the suggested method and information theory methods are used during diagnostics.

Conception and Practical Application of a Measuring Device for Energetic Parameters Measurement of a Mechatronic Object

2011 ◽  
Vol 180 ◽  
pp. 185-193 ◽  
Author(s):  
Aleksy Cwalina ◽  
Marcin Zacharewicz
Keyword(s):  
Synchronous Generator ◽  
Technical Condition ◽  
Measured Quantity ◽  
Structural Elements ◽  
Measuring Device ◽  
Non Invasive ◽  
Invasive Method ◽  
Method Of Evaluation ◽  
Parameters Measurement ◽  
Gas Pressures

In the article assumptions of the developed non-invasive method of evaluation technical condition of selected structural elements of the ship's diesel-electric set at limited monitoring susceptibility, when the engine is not equipped with indicator valves, are discussed. The method is based on simultaneous measurements of phase-to-phase voltage of the synchronous generator, exhaust gas pressures in the exhaust manifold, and vibration accelerations of some parts of the set. To the purpose of the accomplishment all measurements of energetic parameters at the same time, it turned out to be necessary to design and construct the measured quantity converter. In the paper requirements in relation to such a converter, technical project, and representative results of measurements conducted on a real object – diesel-electric set type ZE400/52 – are presented.

scholarly journals Gear Tooth Stress Measurements of Two Helicopter Planetary Stages

1992 ◽  
Author(s):  
Timothy L. Krantz
Keyword(s):  
Load Distribution ◽  
Gear Tooth ◽  
Nasa Lewis Research ◽  
Ring Gear ◽  
Gear Teeth ◽  
Load Variation ◽  
Planet Gear ◽  
Helicopter Main Rotor ◽  
Stress Variations ◽  
Root Location

Abstract Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at the NASA Lewis Research Center. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through the mesh are illustrated. At the tooth root location of the thin-rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three-planet, nonsequential design as compared to that of a four-planet, sequential design. The results reported enhance the data base for gear stress levels and provide data for the validation of analytical methods.

scholarly journals Analysis of repair works to remove the effects of structural failure after a gas explosion

2019 ◽  
Vol 284 ◽  
pp. 02002
Author(s):  
Aleksandra Bąk ◽  
Ryszard Chmielewski
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Technical Condition ◽  
Structural Elements ◽  
Structural Failure ◽  
Gas Explosion ◽  
Gas Explosions ◽  
Construction Supervision ◽  
Bearing Structure ◽  
Construction Works

The article presents the issues of repair works in a multi-family residential building, whose structural and non – structural elements have been damaged and destroyed by a gas explosion and the fire. Gas explosions in residential buildings constitute a small percentage of the total number of building disasters, however, due to the relatively large number of injured people, these incidents are very dangerous [1]. Moreover, the gas explosion often leads to significant material losses and fatalities. Proper assessment of the load-bearing structure after such incident requires an extensive knowledge of the behaviour of structures. The first authority, that issues a decision regarding further use is Construction Supervision Inspector. Until the demolition of the object is ordered, the next step is to provide expert report made by an authorized construction expert, whose aim is to assess the technical condition of the elements of the structure and to determine the scope of necessary repair works. Construction expert, who give such opinion during the assessment of objects immediately after such incident, often has limited access to structural elements, moreover these elements often are covered. Hence, the recommendations contained in these reports often do not include all of required construction works.

Advanced Design and Manufacture of Face-Hobbed Spiral Bevel Gears

2009 ◽  
Author(s):  
V. Simon
Keyword(s):  
Gear Tooth ◽  
Numerical Control ◽  
Mutual Position ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Pinion Gear ◽  
Tooth Surfaces ◽  
Spiral Bevel ◽  
Tooth Flank ◽  
Crown Gear

The design and advanced manufacture of face-hobbed spiral bevel gears on computer numerical control (CNC) hypoid generating machines is presented. The concept of face-hobbed bevel gear generation by an imaginary generating crown gear is established. In order to reduce the sensitivity of the gear pair to errors in tooth-surfaces and to the mutual position of the mating members, modifications are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and/or by using tilt angle of the head-cutter in the manufacture of pinion/gear teeth. The tooth profile modification is introduced by the circular profile of the cutting edge of head-cutter blades. An algorithm is developed for the execution of motions on the CNC hypoid generating machine using the relations on the cradle-type machine. The algorithm is based on the condition that since the tool is a rotary surface and the pinion/gear blank is also related to a rotary surface, it is necessary to ensure the same relative position of the head cutter and the pinion on both machines.

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