KR-102963326-B1 - Evaluation Method of Residual Life of Railroad Vehicles by Prediction of Fatigue Strength of Railroad Vehicles Considering Change of Passenger Load

Abstract

The present invention provides a method for evaluating the remaining lifespan of a railway vehicle based on a railway vehicle fatigue strength prediction technique that considers changes in passenger load, wherein the method involves aggregating the daily passenger load patterns of the railway vehicle by load magnitude and frequency, creating a mathematical model capable of expressing changes in passenger load, performing a fatigue strength evaluation using the model, and evaluating how much longer the vehicle can be used until its expected lifespan.

Inventors

• 전현규

Assignees

• 한국철도기술연구원

Dates

Publication Date

20260511

Application Date

20230519

Claims (7)

1. A first step in which the maximum load of the railway vehicle is calculated; A second step in which daily passenger loads using the above railway vehicle are collected hourly and a daily passenger load pattern is created; A third step in which load size intervals are set based on the daily passenger load pattern created in the second step above, and the frequency is calculated for each interval to obtain a load interval pattern; A fourth step in which a Poisson distribution curve related to the above load section pattern is created; and A method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique that considers changes in passenger load, comprising: a fifth step of performing a cumulative fatigue life evaluation based on the above Poisson distribution curve and calculating the remaining life according to the above load section pattern.
2. In claim 1, A method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique that considers changes in passenger load, characterized in that the maximum load of the first stage above is measured based on the maximum load pattern at the time when the most passengers are on board during daily railway vehicle operation.
3. In claim 2, The above third step is characterized by arranging load magnitudes in order from large to small values and obtaining the load section pattern by varying the width according to the frequency of load occurrence, in a method for evaluating the remaining life of a railway vehicle by a railway vehicle fatigue strength prediction technique considering changes in passenger load.
4. In claim 3, A method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique that considers changes in passenger load, characterized in that the Poisson distribution curve of the above-mentioned fourth step is selected from a plurality of typified Poisson distribution curves that is closest to the actual passenger load distribution pattern.
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Description

Evaluation Method of Residual Life of Railroad Vehicles by Prediction of Fatigue Strength of Railroad Vehicles Considering Change of Passenger Load The present invention relates to a method for evaluating the remaining lifespan of a railway vehicle using a fatigue strength prediction technique that considers changes in passenger load. More specifically, the invention relates to a method for evaluating the remaining lifespan of a railway vehicle using a fatigue strength prediction technique that considers changes in passenger load, wherein a mathematical model capable of expressing changes in passenger load is created by aggregating the frequency of occurrence by load magnitude according to daily passenger boarding patterns reflecting the characteristics of the railway vehicle's operating route, and the fatigue strength is evaluated using this model to assess how much longer the vehicle can be used until its expected lifespan. In the existing railway vehicle fatigue strength evaluation, as shown in Fig. 1, the maximum load at the time when the most passengers are on board during daily railway vehicle operation is used as the standard (peak load), and the evaluation is performed by assuming that a load of the magnitude of the peak load is applied every hour of every day. Assuming that the maximum load acts continuously in this manner, it fails to reflect actual phenomena such as congestion during commuting hours and other times when there are few passengers. Since the lifespan is calculated by assuming a continuous load of an unrealistic magnitude different from reality, fatigue damage occurs that is much greater than what is actually observed in physical phenomena, resulting in a large difference between the predicted and actual values. Therefore, if excessive fatigue damage is predicted, it may lead to over-designed manufacturing and premature scrapping; thus, it is necessary to develop techniques that can realistically reflect passenger load patterns. Figure 1 shows the evaluation of railway vehicle fatigue strength based on the peak load in a full load state using conventional technology. FIG. 2 is a configuration diagram of a railway vehicle remaining life evaluation system based on a railway vehicle fatigue strength prediction technique considering changes in passenger load according to one embodiment of the present invention. FIG. 3 is a conceptual diagram of a railway vehicle remaining life evaluation system based on a railway vehicle fatigue strength prediction technique considering passenger load changes according to one embodiment of the present invention. FIG. 4 is a configuration diagram of a server according to one embodiment of the present invention. FIG. 5 is a configuration diagram of a processing unit according to one embodiment of the present invention. FIG. 6 is a flowchart of a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering changes in passenger load according to an embodiment of the present invention. FIG. 7 is a conceptual diagram of a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering changes in passenger load according to an embodiment of the present invention. FIG. 8 is an example of a daily passenger load pattern in a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering changes in passenger load according to an embodiment of the present invention. FIG. 9 is an example diagram of a load section pattern in a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering passenger load changes according to an embodiment of the present invention. FIG. 10 is an example of a mathematical model curve based on a load section pattern in a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering passenger load changes according to an embodiment of the present invention. FIG. 11 is an example of an SN curve in a method for evaluating the remaining life of a railway vehicle using a railway vehicle fatigue strength prediction technique considering changes in passenger load according to one embodiment of the present invention. FIG. 12 is a test waveform of Evaluation Example 1 of the present invention. FIG. 13 is a cycle counting diagram of Evaluation Example 1 of the present invention. FIG. 14 is a remaining life evaluation diagram of Evaluation Example 1 of the present invention without considering corrosion. Figure 15 is a Poisson distribution curve of Evaluation Example 2 of the present invention. FIG. 16 is a remaining lifespan evaluation diagram of Evaluation Example 2 of the present invention. Figure 17 is a Poisson distribution curve of Evaluation Example 3 of the present invention. FIG.