Research On Urban Rail Transit Vehicle Running Gear Safety Assessment Methodology

At present, it becomes the main trend of transport development to vigorously develop urban rail transit and to establish a "multi-level, three-dimensional integrated transport system ". From October 1969, through 40 years, China has stepped onto the stage of large-scale urban rail transit construction. Currently, rail transit lines have been built in more than 10 cities. Urban rail transportation planning has been developed and under implementation in more than 50 cities with the planning mileage over 7500 km. In the " Twelfth Five-Year " period, the planning and construction of urban rail transit lines will reach the total length of 1,700 kilometers.However, with the rapid development of urban rail transit, the situation of its safety needs more attention, because safety issues and accidents often occur. These failures will not only seriously affect the safety of urban rail traffic vehicles, but also soon lead to huge accident human and economic losses. Safety of urban rail transit vehicles is on the basis of key components of vehicles with running gear as the top priority. In order to improve the safety of urban rail transit operations, through historical data and structural principle analysis, this article takes the vehicle running gear as the research and safety assessment object and carries out the following research:1.The paper systematic analyzes the safety influence parameters of urban rail transit including staff and management, environments, infrastructures, running gear internal factors and maintenance. Meanwhile, in this paper the author constructs the safety assessment architecture of running gear which includes assessment layers, assessment methodologies, assessment flow and safety levels.2.Improved probabilistic influence diagram is applied to construct safety assessment model of urban rail transit vehicle running gear, which improved the targeting and efficiency of operations. This paper proposes reasonable proposals to urban rail companies especially the maintenance department according to the problems reflected in the analysis results.3.Improved analytic hierarchy process (AHP) was implemented to analyze the importance of different parts of running gear. On this basis, it establishes the urban rail transit vehicles running gear fuzzy safety assessment model and gathers risk matrix of fuzzy risk assessment through clustering analysis in AHP. Finally, risk control methods are discussed to reduce risks of the assessment results.4.It proposes a safety assessment method based on the theory of probability statistics reasoning, establishes probability safety model and calculated safety probability through the appropriate model algorithm, which is on the basis of state flow probability in the analysis process of reliability analysis Go methodology which can help judge and locate of inverse probability for system failure and realized a comprehensive probabilistic safety assessment of operational system-parts. And it calculates the safety probability analysis of urban rail transit vehicles running gear in the proposed method.5.Aiming at the characteristics of urban rail transit vehicle running systems, it proposes to acquire vibration signals of urban rail transit vehicles running gear through the sensors, combines wavelet analysis with Fast Fourier Transform and neural network to analyze the vibration velocity or acceleration signals for feature extraction, realizes the purpose of safety assessment of running gear, and achieves remarkable results by actual tests.