PSI - Issue 54

V.M.G. Gomes et al. / Procedia Structural Integrity 54 (2024) 561–567 Author name / Structural Integrity Procedia 00 (2023) 000–000

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Abdullah et. al.. (2019)) have been carried out. Despite prior knowledge in railway dynamics and leaf spring fatigue, this problem still persist, and then the gap in the knowledge about the health of the leaf spring needs to be filled. Since these components have great importance in the safe operation of railway vehicles, a more optimized pre dictive maintenance process is necessary. In this article, a real-time monitoring campaign of the loading imposed and stresses generated in the leaf springs of a freight wagon is collected in order to determine the typical loading distribution observed in this type of freight wagon suspensions. Electric strain gauge is used to monitor surface de formations while potentiometer is installed to collect the displacement imposed to the axle box. The behaviour curves obtained from the numerical model is combined with the experimental data to convert the loading spectrum into a stress spectrum.

2. Methodology

It is planned to conduct a full-scale experimental test of a double-link suspension system under actual driving circumstances. Considered for testing is a two-axle container freight wagon with a double-link suspension system and parabolic leaf springs in each axle. The experiment aims to collect in-time trip data of the wagon, displacements, and leaf spring deformations.

2.1. Container Freight Train Wagon and Testing Route

The wagon under investigation is a platform wagon for transporting containers with the designation Lgnss 22 94 443 3 001 / 100 series. This wagon is 15080 mm long, 2950 mm wide, and 1155 mm high to the top of the platform, with a track gauge of 1435 mm, and with an average weight of 13500 kg. The suspension system as aforementioned consists of a double-link suspension system with a parabolic leaf spring placed one on each wheel. Figure 1 illustrates the freight wagon considered to be investigated. This wagon travels in a specific testing route in Portugal that starts in Entroncamento towards the Port of Leixo˜es, inverts the direction towards to Port of Sines, and then returns to Port of Leixo˜es.

Fig. 1. Freight wagon from series Lgnss 22 94 443 3 001 / 100 investigated.

2.2. Experimental Details

The instrumentation of the freight wagon consists of the installation a potentiometer to gather the relative vertical displacement between the wagon-frame platform and wheel-set as shown in Fig. 2. Additionally, electric strain gauge with reference C4A-06-125SL-350 / 39P (350 Ω ± 0.3 %) is installed to measure longitudinal deformations in the leaf springs. Taking into account the place with the highest failure probability, the strain gauge is glued at 250 mm far from the centre of the leaf springs. The strain gauge is installed carefully, using firstly SCP-1 Silicon Carbide Paper, 220 grit, for finishing, and pos teriorly MCA-1 M-Prep Conditioner A followed by MN5A-1 M-Prep Neutralizer 5A. The M-bond 200 set, which includes an adhesive liquid and a catalyst liquid, is used for bonding. After bonding, nitrile rubber coating (M-Coat B), film coating, and rubber vinyl (Barrier E Butyl Rubber Vinyl) are put on the strain gauge to protect against external conditions. Lastly, the aluminium glue tape is applied and covered with contact glue.