scholarly journals The Absolute Deviation Rank Diagnostic Approach to Gear Tooth Composite Fault

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guangbin Wang ◽  
Wenhui Deng ◽  
Xiaoyang Du ◽  
Xuejun Li
Keyword(s):  
Gear Tooth ◽  
Frequency Doubling ◽  
Diagnostic Approach ◽  
Dynamics Model ◽  
Absolute Deviation ◽  
Single Fault ◽  
Simulating Analysis ◽  
Gear Fault ◽  
The Absolute ◽  
Set Up

Aiming at nonlinear and nonstationary characteristics of the different degree with single fault gear tooth broken, pitting, and composite fault gear tooth broken-pitting, a method for the diagnosis of absolute deviation of gear faults is presented. The method uses ADAMS, respectively, set-up dynamics model of single fault gear tooth broken, pitting, and composite fault gear tooth broken-pitting, to obtain the result of different degree of broken teeth, pitting the single fault and compound faults in the meshing frequency, and the amplitude frequency doubling through simulating analysis. Through the comparison with the normal state to obtain the sensitive characteristic of the fault, the absolute value deviation diagnostic approach is used to identify the fault and validate it through experiments. The results show that absolute deviation rank diagnostic approach can realize the recognition of gear single faults and compound faults with different degrees and provide quick reference to determine the degree of gear fault.

Total Synthesis of (–)-Strempeliopine via Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation

2021 ◽  
Author(s):  
Yi An ◽  
Mengjuan Wu ◽  
Weijian Li ◽  
Yaling Li ◽  
Zhenzhen Wang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Allylic Alkylation ◽  
Asymmetric Allylic Alkylation ◽  
Enantioselective Total Synthesis ◽  
Synthetic Strategy ◽  
Palladium Catalyzed ◽  
The Absolute ◽  
Set Up

Reported herein a concise and enantioselective total synthesis of Schizozygine alkaloids (–)-strempeliopine. This synthetic strategy features a palladium-catalyzed decarboxylative asymmetric allylic alkylation of N-benzoyl lactam to set up the absolute...

Application of PPP Solution to Determine the Absolute Vertical Crustal Movements: Case Study for Northeastern Europe

2017 ◽  
Author(s):  
Kamil Kowalczyk ◽  
Janusz Bogusz
Keyword(s):  
Time Series ◽  
Vertical Movements ◽  
Crustal Movements ◽  
Northeastern Poland ◽  
The Absolute ◽  
Set Up ◽  
Changes Over Time ◽  
The Relationship ◽  
Vertical Crustal Movements

To estimate the relationship between vertical movements of the Earth’s crust, geoid temporal changes and Mean Sea Level (MSL) variations, a knowledge about the absolute (determined from satellite and space techniques) height changes over time is required. In this paper, we give an idea of determining the height changes with a use of Vertical Switching Edge Detection (VSED) algorithm. On the basis of the least squares estimation, the VSED method detects the discontinuities in time series and determines the values of jumps at the same time. We used the time series from PPP (Precise Point Positioning) solution obtained in NGL (Nevada Geodetic Laboratory) using satellite data gathered at more than 50 permanent stations located in Latvia, Lithuania and northeastern Poland. The minimum time span of data was set up to 3 years. Data were pre-analyzed by removing outliers and interpolating small gaps. The obtained results give an overview of a possibility of the proposed method to be used and the ongoing vertical movements on the area we considered.

Modeling and Simulation of the PMSM-Precision Reducer System with Modelica

2012 ◽  
Vol 201-202 ◽  
pp. 202-207
Author(s):  
Zhi Hua Li ◽  
Hong Guang Yang ◽  
Jun Yu ◽  
You Ping Gong
Keyword(s):  
Modeling And Simulation ◽  
Electromechanical Coupling ◽  
Permanent Magnet Synchronous Motor ◽  
Unified Modeling Language ◽  
Simulation Method ◽  
System Control ◽  
Dynamics Model ◽  
Physical Systems ◽  
Set Up ◽  
Complex Electromechanical Systems

There is still lack of effective modeling and simulation method for complex electromechanical coupling system. Modelica is a multi-domain unified modeling language to solve the modeling and simulation problems of the complex and heterogeneous physical systems. Dymola is a Modelica-based modeling and simulation platform for the complex physical systems. In this paper, the dynamics model of the permanent magnet synchronous motor (PMSM)-precision reducer system is established using Lagrange-Maxwell equation. The simulation model of this system is set up with Modelica language. The simulation of the system is realized in Dymola. Results show that the system can respond to good static and dynamic characteristics under a given speed for different loads. The dynamics model of the PMSM-precision reducer system can be further used in system control and optimization. The proposed modeling and simulation method based on Modelica may be commonly applied to other complex electromechanical systems.

Modeling and Workplace Analysis of 3T Cable-Driven Parallel Manipulator

2013 ◽  
Vol 415 ◽  
pp. 519-523
Author(s):  
Li Wen Guan ◽  
Cheng Long Mu ◽  
Yu Jian Hu
Keyword(s):  
Numerical Simulation ◽  
Dynamic Modeling ◽  
Parallel Manipulator ◽  
Inverse Dynamics ◽  
Comprehensive Analysis ◽  
Dynamics Model ◽  
Set Up

This paper analyzes the dynamic modeling and workplace of the 3T cable-driven parallel manipulator. The mechanism utilizes four cables to driven. Firstly, the kinematics equations and the inverse dynamics model were set up for the analysis. And then, pseudo-drag is a serious problem in cable-driven parallel manipulator, this paper give a method to find the workplace under the condition of pseudo-drag. Finally, through numerical simulation, the workplace of the mechanism satisfying the demand is presented by comprehensive analysis.

Gear fault detection using dynamic transmission variance

2018 ◽  
Vol 24 (1) ◽  
pp. 101-118 ◽  
Author(s):  
Chris K. Mechefske ◽  
David Benjamin Rapos ◽  
Markus Timusk
Keyword(s):  
Signal Processing ◽  
Fault Detection ◽  
Gear Tooth ◽  
Operational Mode ◽  
Content Type ◽  
Input Shaft ◽  
Gear Mesh ◽  
Rotational Position ◽  
Gear Fault ◽  
Plastic Gears

Purpose The purpose of this paper is to report the findings of a study that used measurements of shaft relative rotational position, made using inexpensive Hall Effect sensors and magnets mounted at the ends of a gearbox input and output shafts, to determine gear “transmission variance.” The transmission variance signals, as a function of gear/shaft rotational position, were then used to detect and diagnose gear faults. Design/methodology/approach Two sets of spur gears (one plastic and one steel) were used to experimentally determine the relative shaft rotational position between the input and the output gearbox shafts. Fault-free and faulted (damaged tooth faces and cracked tooth bases) gears were used to collect representative dynamic signals. Signal processing was used to extract transmission variance values as a function of shaft rotational position and then used to detect and diagnose gear faults. Findings The results show that variations in the relative rotational position of the output shaft relative to that of the input shaft (the transmission variance) can be used to reveal gear mesh characteristics, including faults, such as cracked or missing gear teeth and flattened gear tooth faces, in both plastic gears and steel gears under appropriate (realistic) loads and speeds. Research limitations/implications The operational mode of the non-contact rotational position sensors and the dynamic accuracy limitations are explained along with the basic signal processing required to extract transmission variance values. Practical implications The results show that shaft rotational position measurements can be made accurately and precisely using relatively inexpensive sensors and can subsequently reveal gear faults. Social implications The inexpensive and yet trustworthy fault detection methodology developed in this work should help to improve the efficiency of maintenance actions on gearboxes and, therefore, improve the overall industrial efficiency of society. Originality/value The method described has distinct advantages over traditional analysis methods based on gearbox vibration and/or oil analysis.

scholarly journals On the determination of the absolute unit of resistance by alternating current methods

1912 ◽  
Vol 87 (597) ◽  
pp. 391-414 ◽  
Keyword(s):  
Lower Order ◽  
Alternating Current ◽  
National Physical Laboratory ◽  
Mutual Inductance ◽  
Electrical Circuits ◽  
Physical Laboratory ◽  
Absolute Measure ◽  
The Absolute ◽  
Set Up

1. Introductory .—Recently at the National Physical Laboratory we have constructed a standard of mutual inductance of novel type, whose value has been accurately calculated from the dimensions. This inductance has formed the basis for the determination of the unit of resistance in absolute measure by two different methods, in both of which alternating current is employed. Although there is no doubt that the accuracy attainable by these methods could be increased by greater elaboration of the apparatus used, the results already obtained seem to be of sufficient interest to warrant publication. It should be mentioned that the accuracy here aimed at was of a considerably lower order than that contemplated in the determination of the ohm by the Lorenz apparatus which is at present being carried out in the laboratory. For the experiments here described, no apparatus was specially constructed, but use was made of instruments which had already been designed and set up for the measurement of inductance and capacity. I shall first give a brief description of the standard inductance and then pass on to the methods and results. 2. Standard Mutual Inductance .—The design of the mutual inductance has already been described. The electrical circuits have the form and arrange­ment shown in section in fig. 1.

The Dynamics Analysis of a Multi-Stage Hybrid Planetary Gearing

2012 ◽  
Vol 538-541 ◽  
pp. 2631-2635
Author(s):  
Xin Tan ◽  
Yao Li ◽  
Jun Jie Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Gear Tooth ◽  
The Finite Element Method ◽  
Dynamics Model ◽  
Multi Stage ◽  
Body Dynamics ◽  
Multi Body ◽  
Rich Spectrum ◽  
Element Method

This paper introduces a complex multi-body dynamics model which is established to simulate the dynamic behaviors of a multi-stage hybrid planetary gearing based on the finite element method and the software ADAMS. The finite element method is used to introduce deformable ring-gears and sun-gears by using 3D brick units. A whole multi-body dynamics model is established in the software ADAMS. Mesh stiffness variation excitation and gear tooth contact loss are intrinsically considered. A rich spectrum of dynamic phenomena is shown in the multi-stage hybrid planetary gearing. The results show that the static strength of main parts of the gearing is strong enough and the main vibration and noises are excited by the dynamic mesh forces acting on the tooth of planet-gears and ring-gears.

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