A Method for Detecting Temperature Force Based on Rail Vertical Acceleration Power Spectral Density

Abstract

The invention discloses a method for detecting temperature force based on rail vertical acceleration power spectrum density, comprising the following steps: taking a test rail whose length is one span length, determining the sensitive excitation point and sensitive response point of the test rail; pre-measurement and acquisition A plurality of sets of the temperature variation of the seamless line rail and its corresponding vertical vibration characteristic peak frequency, after fitting each group of data, a fitting curve f=A*t of the vertical characteristic peak frequency-temperature variation is obtained + B, repeat the above steps to obtain the fitting curves under different fastener spacing; actually measure the seamless line rail of a span length, obtain its vertical vibration characteristic peak frequency f and fastener spacing, according to the measured fastener Select the corresponding fitting curve for the spacing, and calculate the longitudinal temperature stress. The invention has the advantages that only one span length of rail is taken as a single detection object, only one acceleration sensor is needed to realize continuous measurement of the line, and the influence of fastener spacing on measurement results is eliminated.

Description

technical field [0001] The invention relates to the technical field of transportation, in particular to a method for detecting temperature force based on rail vertical acceleration power spectral density. Background technique [0002] The seamless line eliminates the rail joints through welding, greatly enhances the passability of the train, improves the comfort of passengers, and reduces the impact of the wheel and rail when the train passes, reducing the power of the train and track structure Response and vibration and noise effects on the surrounding environment improve the service life of track structures and train components, so seamless lines are widely used. However, because the seamless line eliminates the rail joints, the rail cannot freely expand and contract longitudinally along the line when the temperature changes, resulting in temperature forces. The rails were broken, threatening the safe operation of the train. Therefore, the detection of the temperature fo...

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Problems solved by technology

Among them, the main disadvantage of the Barkhausen method, ultrasonic guided wave method, and X-ray method is that it can only detect the stress distribution of the shallow surface layer of the rail, and is greatly affected by internal defects of the rail such as rail head nuclear damage, which cannot reflect the overall stress distribution well. Stress distribution on the rail section

[0004] The existing temperature force detection method based on rail vibration characteristics takes a section of rail as the detection object, and arranges multiple excitation points and vibration pickup points on the rail of the test section. The modal frequency indirectly reflects the temperature force of the rail through the modal frequency of the rail, but there are three main problems in this method: (1) Multiple excitation points and vibration pickup points need to be arranged during the detection operation, and each excitation point needs to be Sequential excitation is carried out, and the modal frequency is calculated through the collected force signal and response signal. The amount of data collected during the detection process is large, and it takes a long time to arrange sensors and apply excitation during operation, which is limited by the short maintenance time of the railway engineering department. reality of

(2) The modal frequency is greatly affected by the spacing of the fasteners. Due to the uneven distribution of the spacing of the fasteners on the ballasted track seamless line, continuous detection of the ballasted seamless line will affect the detection of this method The results are accurate, so this method is suitable for fixed-point detection of temperature forces on ballasted track seamless lines, but it is difficult to achieve continuous detection of rail temperature forces on continuous ballasted track seamless lines

(3) During the detection process of this method, manual movement is required to stimulate specific location measurement points, which makes it difficult to develop unmanned detection devices for this method, so the application prospect has certain limitations

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