Analysis and prediction of the width of spreading carbon fiber tow based on gray system theory

2020 ◽  
Vol 138 (12) ◽  
pp. 50069
Author(s):  
Qihong Zhou ◽  
Guangzong Wu ◽  
Zhenxi Wang ◽  
Bing Wang ◽  
Ge Chen ◽  
...  
Keyword(s):  
System Theory ◽  
Carbon Fiber ◽  
Gray System Theory ◽  
Gray System

Study on Life of Concrete Eroded by Seawater

2012 ◽  
Vol 476-478 ◽  
pp. 1612-1615
Author(s):  
Yue Zhong Lin
Keyword(s):  
System Theory ◽  
Test Data ◽  
Concrete Strength ◽  
Forecast Model ◽  
Strength Loss ◽  
Loss Coefficient ◽  
Gray System Theory ◽  
Gray System

According to the data of concrete strength in different circulation, this paper put forward a idea of concrete strength loss coefficient and established a forecast model of concrete life by the gray system theory. As a result, it shows that the relativity and definition are better between the model with test data. This model can be used to forecast the life of concrete eroded by seawater.

Fault Diagnosis Based on Qualitative Data by Gray System Theory

2014 ◽  
Vol 644-650 ◽  
pp. 1227-1229
Author(s):  
Li Zhang ◽  
Zhi Jian Liu ◽  
Da Lin Sun ◽  
Dian Hua Yang
Keyword(s):  
System Theory ◽  
Fault Diagnosis ◽  
Qualitative Data ◽  
Traditional Methods ◽  
Gray System Theory ◽  
Gray System ◽  
Positioning Method ◽  
Short Time

Gray system theory is good at dealing with the uncertain problems with a little amount of data. Some equipment’s fault data is abundant, and fault phenomenon is not explicit, uncertain and qualitative. So, it is difficult to diagnosing this kind fault through the traditional methods in a short time. This paper analyzes the data’s feature and then makes quantitative processing. The result shows that by this model, fault diagnosis can be simplified and quickly. And it is proved that the new kind of fault-positioning method for quick diagnosis is effective and efficient.

Impact analysis and classification of aircraft functional failures by using improved FHA based on gray correlation

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuhang Zhang ◽  
Yan Huang ◽  
Tingting Xu ◽  
Chang Liu ◽  
Liangyan Tao
Keyword(s):  
System Theory ◽  
Evaluation Model ◽  
Civil Aviation ◽  
Aviation Industry ◽  
Content Type ◽  
Gray System Theory ◽  
Gray System ◽  
State Classification ◽  
Failure State

Purpose The classification of aircraft failures has been a significant part of functional hazard analysis (FHA). Aiming at the shortcomings of the traditional FHA method in the evaluation of aircraft risk, the purpose of this paper is to put forward a new approach by combining the gray comprehensive relation calculation method in the gray system theory with the traditional FHA in order to deal with the problem of “little data, poor information.” Design/methodology/approach This paper combines FHA, 1–9-scale method and gray relation analysis. At first, aircraft failure scenarios are chosen and data from experts are collected; then gray system theory is applied to find the relevance of such scenarios. Finally, the classification according to relevance is determined. Findings In the past, “little data, poor information” made it difficult for researchers to implement FHA. In this paper, the authors manage to deal with the problem of “poor information” and provide an approach to find the seriousness of aircraft failure. Research limitations/implications Due to the use of expert-evaluating methods, the classification of failures is still a little subjective and can be improved in this area. In the future, the method can be improved from the perspective of combining FMEA to analyze more complex indicators or using multisource heterogeneous solutions to solve fuzzy numbers, probabilities, gray numbers and indicators that cannot be assigned. Practical implications The paper uses FHA to divide the failure state and establishes a gray evaluation model of the aircraft failure state classification to verify the relevant method. Some aircraft safety design requirements are used to check the safety hazards of the aircraft during the design process, and to provide rational recommendations for the functional design of the aircraft. Social implications Improving the safety of aircraft is undoubtedly of great practical significance and has become a top priority in the development of the civil aviation industry. In this paper, the FHA method and the failure state of the aircraft are studied. The original FHA method is innovated by using the gray system theory applicable to the poor information state. Therefore, to some extent, this study has significance for improving the safety of civil aircraft flight, ensuring people’s travel safety and enhancing the society’s trust in civil aviation. Originality/value The main innovation of this paper is integrating the FHA method and the gray system theory. This study calculates the comprehensive relation degree of each failure under different flight stages, and uses FHA to divide the failure state, and finally establishes a gray evaluation model of the aircraft failure state classification to analyze the different conditions of the landing gear brake system, so that it improves the present situation, and the problem with the character of “little data, poor information” can be addressed better.

Research of Airfield Lighting Insulation Resistance Prediction Based on Gray System Theory

2012 ◽  
Vol 263-266 ◽  
pp. 1279-1284
Author(s):  
Xiu Yan Wang ◽  
Cui Fang Li ◽  
Zong Shuai Li ◽  
Jia Quan Lin
Keyword(s):  
System Theory ◽  
Insulation Resistance ◽  
Lighting System ◽  
Gray System Theory ◽  
Gray System ◽  
International Airport ◽  
Resistance Prediction ◽  
Predicted Values ◽  
Isolation Transformers ◽  
Resistance Value

Airfield lighting circuit is an important part of airfield lighting system, and the insulation resistance value of this circuit is affected by humidity, temperature, the quality and the number of the Isolation Transformers and many other factors, so it is difficult to accurately predict the resistance size by using traditional methods. In the light of insulation resistance values of airfield lighting circuit, this paper put forward adopting Gray System Theory to make the prediction, and then build GM(2,1) model to analyze and forecast the resistance values according to the actually measured values of the insulation resistance at Shanghai Pudong International Airport. Finally, the research shows that there is only a little difference between predicted values and the actually measured values. In other words, the prediction of insulation resistance based on Gray System Theory is viable.

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