CN-122021046-A - Fatigue performance evaluation method for steel rail fastener

CN122021046ACN 122021046 ACN122021046 ACN 122021046ACN-122021046-A

Abstract

The invention relates to a fatigue performance evaluation method for a steel rail fastener, and belongs to the technical field of rail transit. The method comprises the steps of obtaining actual measurement wheel rail force data of all trains passing through fasteners all the day, wherein the data comprise vertical wheel rail force, transverse wheel rail force and the times of passing through the fasteners, and calculating normal use limit state values and bearing capacity limit state values under linear working conditions and curve working conditions from four dimensions of use states, loading times, loading amplitude values and loading angles according to test data. According to the invention, by introducing a load more suitable for practical limit state of engineering and combining multiple frequencies, multiple loading angles and loading times matched with predicted service life of the fastener and line operation density, a comprehensive loading strategy is constructed to develop fatigue performance assessment, so that the accuracy of fatigue performance assessment of the steel rail fastener system can be remarkably improved.

Inventors

LIU YONGQIANG
ZHANG PEIJIE
LIAO YINGYING
ZHANG HOUGUI
WANG BAOSEN
ZHAO YIWEI

Assignees

石家庄铁道大学

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (5)

1. A method for evaluating fatigue performance of a rail fastener, comprising: the method comprises the steps of obtaining test data generated when all trains pass through the fasteners all day, wherein the test data comprise the vertical force of a steel rail, the transverse force of the steel rail and the times of passing through the fasteners; and according to the test data and the designed service life of the steel rail fastener, calculating a normal use limit state value and a bearing capacity limit state value under a linear working condition and a curve working condition from four dimensions of a use state, loading times, loading amplitude and loading angles respectively.
2. A method of evaluating fatigue performance of a rail fastener according to claim 1, wherein calculating normal use limit state values and load bearing capacity limit state values under straight line conditions and curved line conditions from the use state dimensions comprises: under the linear working condition, calculating a peak value sequence of the vertical force according to the test data, and sequencing from large to small according to the peak value sequence; Taking the first 5% of the peak value sequence as a bearing capacity limit state, and dividing a quantile value; calculating an all-day normal use limit state set and an all-day bearing capacity limit state set according to the split values; Under the curve working condition, dividing test data into a transverse force sequence, a vertical force sequence and a derailment coefficient sequence; judging a normal use state and a bearing capacity state according to the derailment coefficient sequence; And obtaining a load set in a normal use state and a bearing capacity state according to the transverse force sequence and the vertical force sequence.
3. The method for evaluating the fatigue performance of a steel rail fastener according to claim 1, wherein the normal use limit state value and the bearing capacity limit state value under the linear working condition and the curve working condition are calculated from the loading frequency dimension, and the method comprises the following steps: Under the linear working condition, according to the test data and the designed service life, calculating the total number of loading of the whole life cycle in the normal service limit state and the total number of loading of the whole life cycle in the bearing capacity limit state; Under the curve working condition, calculating the total number of load in the limit state of the bearing capacity and the total number of load in the limit state of normal use in all days according to the test data; And calculating the total number of loading of the whole life cycle of the bearing capacity limit state and the total number of loading of the whole life cycle of the normal use limit state according to the total number of loading of the bearing capacity limit state and the total number of loading of the normal use limit state and the designed service life.
4. The method of claim 1, wherein calculating normal use limit state values and load bearing capacity limit state values under linear and curved conditions from the load amplitude dimension comprises: screening a vertical force sequence of the whole day according to the test data, and performing half sine wave fitting on the vertical force sequence to obtain a fitting curve containing amplitude, median and frequency; correcting the amplitude of the vertical force to obtain a loading force; dividing the fitted curve into intervals, and calculating the representative value of each interval; grouping the loading forces according to intervals, and counting the cycle times of the loading forces in each interval; The cycle times are loading amplitude cycle times of the full-day normal use limit state and the bearing capacity limit state under the linear working condition and the curve working condition, and the full-life cycle loading amplitude cycle times under the linear working condition and the curve working condition are obtained by combining the design years.
5. The method of claim 1, wherein calculating normal use limit state values and load bearing capacity limit state values under straight line conditions and curve conditions from the load angle dimension comprises: Under the linear working condition, in the limit state without bearing capacity, the loading angle of the normal use limit state is obtained by calculating the ratio of the transverse force to the vertical force of the steel rail; Under a curve working condition, the derailment coefficient is smaller than or equal to 0.75 and is in a normal use limit state, the derailment coefficient is divided into a plurality of representative intervals, and the loading angles corresponding to the intervals are a i =arctan(R i respectively (i=1, 2, the number of the loading angles is equal to n); And the derailment coefficient is larger than 0.75 and is the load-bearing capacity limit state, and the loading angle of the normal use limit state is obtained by calculating the ratio of the transverse force to the vertical force of the steel rail.

Description

Fatigue performance evaluation method for steel rail fastener Technical Field The invention relates to the technical field of rail transit, in particular to a method for evaluating fatigue performance of a steel rail fastener, which is more suitable for engineering practice. Background Fasteners are defined as the assembly of components that secure the rail to the support structure and hold it in the desired position while allowing any necessary vertical, lateral and longitudinal movement. It is an important component of a track system, and its main functions include connecting rails and sleepers into an integral structure, fixing rail positions, and maintaining geometric position stability of the track structure. In addition, in order to adapt to the higher requirements of subway lines on vibration and noise control, part of fastener systems also have a vibration reduction function, and the vibration level transmitted to vibration sources and surrounding environments in the running process of a train can be effectively reduced. According to the current rail transit equipment management system, the fastener system must undergo performance evaluation under the fatigue load condition before being put into use so as to ensure that the fastener system meets the requirements of safety and reliability of long-term service. However, the existing standardized test methods are all evaluated based on the assumed load condition, and the differences of the subway line in the actual service process, such as factors of structural form, train running frequency, axle weight distribution, service life and the like, cannot be fully considered. This results in a possible significant deviation between the fatigue life prediction results under laboratory conditions and the actual service conditions. The related art generally works around linear criteria with less consideration by the system to the impact of different train consist and wheel operating conditions on fastener force amplitude fluctuations during loading. If these extreme conditions are ignored, only a single, fixed loading mode is adopted, and it is difficult to truly reveal the mechanical response characteristics of the fastener system under actual operating conditions. In addition, the setting of the fatigue loading times (300 ten thousand times as the current standard) has comprehensive consideration based on the actual service life of the fastener and the running density of the circuit, and the performance attenuation process of the fastener in the whole life cycle is often difficult to accurately map. Disclosure of Invention The invention aims to provide a method for evaluating fatigue performance of a steel rail fastener, which is used for improving the evaluation accuracy of performance attenuation of the steel rail fastener in a whole life cycle. In order to achieve the above object, the present invention provides the following technical solutions: a method for evaluating fatigue performance of a rail fastener, comprising: the method comprises the steps of obtaining test data generated when all trains pass through the fasteners all day, wherein the test data comprise the vertical force of a steel rail, the transverse force of the steel rail and the times of passing through the fasteners; and according to the test data and the designed service life of the steel rail fastener, calculating a normal use limit state value and a bearing capacity limit state value under a linear working condition and a curve working condition from four dimensions of a use state, loading times, loading amplitude and loading angles respectively. The further technical scheme is that the normal use limit state value and the bearing capacity limit state value under the straight working condition and the curve working condition are calculated from the use state dimension, and the method comprises the following steps: under the linear working condition, calculating a peak value sequence of the vertical force according to the test data, and sequencing from large to small according to the peak value sequence; Taking the first 5% of the peak value sequence as a bearing capacity limit state, and dividing a quantile value; calculating an all-day normal use limit state set and an all-day bearing capacity limit state set according to the split values; Under the curve working condition, dividing test data into a transverse force sequence, a vertical force sequence and a derailment coefficient sequence; judging a normal use state and a bearing capacity state according to the derailment coefficient sequence; And obtaining a load set in a normal use state and a bearing capacity state according to the transverse force sequence and the vertical force sequence. The further technical scheme is that the normal use limit state value and the bearing capacity limit state value under the linear working condition and the curve working condition are calculated from the loading times dimension, and the method