Fault Mechanism Analysis and Characteristic Extraction for Multi-Disc Clutch

2014 ◽  
Vol 526 ◽  
pp. 155-163
Author(s):  
Man Chen ◽  
He Yan Li ◽  
Biao Ma
Keyword(s):  
High Frequency ◽  
Initial Phase ◽  
Friction Pair ◽  
Vibration Signal ◽  
Coupling Model ◽  
Dynamics Simulation ◽  
Mechanism Analysis ◽  
The Difference ◽  
Vibration Signal Analysis ◽  
The Impact

The thermo-elastic coupling model of clutch friction pair is established by the thermoelastic instability theory to acquire the basic process of friction disc warp due to hot agglomeration; according to this process, thought of reflecting initial phase clutch fault by observing the partial deformation generated by hot spots is proposed in this paper. And based on this thought, the multi-disc clutch dynamics simulation model is established to acquire the dynamic characteristics existing on the friction pair when tiny deformation happens; according to vibration characteristics of this characteristics and the feature that the interference noise of the high frequency section of the transmission system is comparatively light, and based on the analysis on the difference of frequency spectrum of the high frequency section before and after shifting gears, a new kind of initial phase multi-disc clutch fault diagnosing method based on vibration signal analysis is proposed. The test results further prove that, this method can be used to extract the impact vibration generated by tiny deformation happened on the friction pair, and is hopeful to be used in the practical engineering of initial phase multi-disc clutch fault diagnosing.

The Material Mechanism Analysis of Airliner Forced Landing onto Water

2013 ◽  
Vol 830 ◽  
pp. 64-67
Author(s):  
Zhen Li Sun ◽  
Jun Jun Du ◽  
Chao Liu ◽  
Meng Yu Li ◽  
She Sheng Zhang
Keyword(s):  
Difference Equation ◽  
Solid Material ◽  
Numerical Results ◽  
Mechanism Analysis ◽  
Forced Landing ◽  
Impact Acceleration ◽  
The Difference ◽  
The Impact ◽  
Sliding Distance

The paper concentrates on the material mechanism analysis of airliner landing onto water in slide decelerating stage. According to the solid material, the difference equation is constructed to find the posture of airliner with different angles Our numerical results show that the impact of stormy wave may make airliner out of balance, impact acceleration is inversely proportional to the sliding distance, .

Pelletization Quality Simulation for Operation Uncertainty of Die-Plate Based on Liquid-Solid-Liquid Coupling Model

2012 ◽  
Vol 557-559 ◽  
pp. 2266-2273 ◽  
Author(s):  
Xiao Feng Liu ◽  
Fu Qiao Liu ◽  
Bao Hai Yu ◽  
Chao Bi ◽  
Bing Zhang
Keyword(s):  
Large Scale ◽  
Flow Distribution ◽  
Coupling Model ◽  
Evaluation Framework ◽  
Mechanism Analysis ◽  
Operation Condition ◽  
Fem Method ◽  
Simulation And Evaluation ◽  
Solid Liquid ◽  
The Impact

As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization quality. Flow fluctuation of extruder and die-hole blocking can be summarized as two uncertainties for pelletization quality problem. A Liquid-Solid-Liquid coupling FEM method is presented to simulate factors of temperature distribution, flow distribution and flow rate control. Based on the calculations and mechanism analysis, pelletization quality degree and assessment framework are designed and calculated to analyze the impact of operation uncertainties to final product. With the simulation and evaluation framework, control methods for pelletization quality are discussed for Die-plate design and operation condition settings.

scholarly journals Does the Construction of National Eco-Industrial Demonstration Parks Improve Green Total Factor Productivity? Evidence from Prefecture-Level Cities in China

2021 ◽  
Vol 14 (1) ◽  
pp. 26
Author(s):  
Lu Liu ◽  
Xiaodong Yang ◽  
Yuxin Meng ◽  
Qiying Ran ◽  
Zilian Liu
Keyword(s):  
Total Factor Productivity ◽  
Industrial Structure ◽  
Mediation Effect ◽  
Eastern Region ◽  
Mechanism Analysis ◽  
Natural Experiments ◽  
Factor Productivity ◽  
The Difference ◽  
The Impact ◽  
Industrial Demonstration

This study conducted quasi-natural experiments based on the panel data of 239 prefecture-level cities in China from 2005 to 2017. The difference-in-difference (DID) and mediation effect model are used to test the impact and mechanism of the construction of national eco-industrial demonstration parks (NEDP) on green total factor productivity (GTFP). The results show that: (1) The construction of NEDP has significantly improved the urban GTFP, and the conclusion is still valid after running the robustness test. (2) Mechanism analysis shows that the construction of NEDP has improved GTFP through technological innovation and industrial structure upgrading. (3) The heterogeneity results reveal that NEDP has a significant positive effect on GTFP in the central and western regions, while the effect was insignificant in the eastern region. Moreover, NEDP significantly contributes to GTFP in resource-based and non-resource-based cities, while the contribution of resource-based cities is greater than that of non-resource-based cities. This study provides a reference for China to further promote the construction quality of NEDP and green development.

Application of Hilbert-Huang Transform to Vibration Signal Analysis of Coal and Gangue

2010 ◽  
Vol 40-41 ◽  
pp. 995-999 ◽  
Author(s):  
Wei Liu
Keyword(s):  
Signal Analysis ◽  
Vibration Signal ◽  
Intrinsic Mode Function ◽  
Frequency Interval ◽  
Hilbert Huang Transform ◽  
Mode Function ◽  
Mode Decomposition ◽  
Marginal Spectrum ◽  
The Difference ◽  
Vibration Signal Analysis

In this paper, a new method of vibration signal analysis of coal and gangue based on Hilbert-Huang transform is presented. Empirical mode decomposition algorithm was used to decompose the original vibration signal of coal and gangue into the intrinsic modes for further extract useful information contained in response signals under complicated environment. By analyzing local Hilbert marginal spectrum and local energy spectrum of the first four intrinsic mode function components, we found the difference of coal and rock in specific frequency interval that the amplitude and energy mainly distributed at frequency interval between 100Hz and 600Hz when coal was drawn, while the amplitude and energy were more concentrated at 1000Hz or so when gangue was drawn. Furthermore, the further analysis result from marginal spectrum of each intrinsic mode function component agreed well with the conclusion above. So the extracted features with the propose approach can be served as coal and gangue interface recognition.

scholarly journals Vibration Signal Analysis of Chimney Blasting Based on HHT

2021 ◽  
Author(s):  
Sen Huang ◽  
Linna Li ◽  
Dongwang Zhong ◽  
Li He ◽  
Jianfeng Si
Keyword(s):  
Vibration Signal ◽  
Blasting Vibration ◽  
Feature Identification ◽  
Hilbert Huang Transform ◽  
High Rise ◽  
Mode Decomposition ◽  
Marginal Spectrum ◽  
Vibration Signal Analysis ◽  
The Impact ◽  
Instantaneous Energy

In the blasting demolition processs of high-rise structures, the impact of blasting vibration to the environment and objects to be protected must be effectively controlled, so the blasting vibration signal is deeply analyzed [1]. In this paper, the blasting vibration signal of a chimney is analyzedbased on HHT. The blasting vibration signal is denoised by Empirical Mode Decomposition (EMD)-wavelet threshold, then using Hilbert-Huang Transform (HHT) [2] the measured blasting vibration waveform Hilbert spectrum, marginal spectrum and instantaneous energy graph are draw to analyze the chimney blasting vibration. The results show that the denoising effect of EMD-wavelet threshold is good for blasting vibration signal [3]. HHT method has a good feature identification ability when processing vibration signals, and can reflect the characteristics of data more comprehensively and accurately, which provides convenience for the study of vibration signal data.

scholarly journals Recipes for Correcting the Impact of Effective Mesoscale Resolution on the Estimation of Extreme Winds

2012 ◽  
Vol 51 (3) ◽  
pp. 521-533 ◽  
Author(s):  
Xiaoli Guo Larsén ◽  
Søren Ott ◽  
Jake Badger ◽  
Andrea N. Hahmann ◽  
Jakob Mann
Keyword(s):  
High Frequency ◽  
Mesoscale Model ◽  
Energy Deficit ◽  
Smoothing Effect ◽  
Model Resolution ◽  
Extreme Wind ◽  
The Difference ◽  
Extreme Winds ◽  
The Impact ◽  
Good Agreement

AbstractExtreme winds derived from simulations using mesoscale models are underestimated because of the effective spatial and temporal resolutions. This is reflected in the spectral domain as an energy deficit in the mesoscale range. The energy deficit implies smaller spectral moments and thus underestimation in the extreme winds. The authors have developed two approaches for correcting the smoothing effect resulting from the mesoscale model resolution that impacts the extreme wind estimation by taking into account the difference between the modeled and measured spectra in the high-frequency range. Both approaches give estimates of the smoothing effect that are in good agreement with measurements from several sites in Denmark and Germany.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

Evaluation of the impact of public investment programs on social and economic performance of territories

2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena
Keyword(s):  
Bayesian Modeling ◽  
Positive Impact ◽  
Public Investment ◽  
Difference In Differences ◽  
The Public ◽  
Export Activity ◽  
Regional Investment ◽  
The Difference ◽  
The Impact ◽  
Development Institution

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.

The Use of Multimedia and its Impact on Bangladeshi EFL Learners at Tertiary Level

2020 ◽  
Vol 4 (2) ◽  
pp. 150
Author(s):  
Farzana Sharmin Pamela Islam
Keyword(s):  
Language Learning ◽  
Academic Writing ◽  
Teaching And Learning ◽  
English Language ◽  
Capital City ◽  
Tertiary Level ◽  
Language Classroom ◽  
The Difference ◽  
The Government ◽  
The Impact

As 21st century is the era of modern technologies with different aspects, it offers us to make the best use of them. After tape recorder and overhead projector (OHP), multimedia has become an important part of language classroom facilities for its unique and effective application in delivering and learning lesson. Although in many parts of Bangladesh, a South Asian developing country, where English enjoys the status of a foreign language, the use of multimedia in teaching and learning is viewed as a matter of luxury. However, nowadays the usefulness and the necessity of it are well recognized by the academics as well as the government. The study aims to focus on the difference between a traditional classroom void of multimedia and multimedia equipped classrooms at university level by explaining how multimedia support the students with enhanced opportunity to interact with diverse texts that give them more in-depth comprehension of the subject. It also focuses on audio-visual advantage of multimedia on the students’ English language learning. The study has followed a qualitative method to get an in-depth understanding of the impact of using multimedia in an English language classroom at tertiary level. For this purpose, the data have been collected from two different sources. Firstly, from students’ written response to  an open ended question as to their comparative experience of learning  lessons with and without multimedia facilities; and secondly, through  observation of English language classes at a private university of Dhaka, the capital city of Bangladesh. The discussion of the study is limited to  the use of multimedia in English language classroom using cartoons, images and music with a view to enhance students’ skills in academic writing, critical analysis of image and critical appreciation of music. For this purpose, cartoons in English language, images from Google and music from You Tube have got focused discussion in this paper.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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