PSI - Issue 19

Anne Coulon et al. / Procedia Structural Integrity 19 (2019) 665–673 Coulon / Structural Integrity Procedia 00 (2019) 000–000

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Loads on the MPL75 car body are compared in specific operating conditions with empty and full loads to reference in Table 1. Regarding those results, the car body load is an important parameter. Number of cycles count for full load is more than 10 times higher than the empty load in the vertical direction. In full load extreme conditions during the whole car body life, the equivalent number of acceleration cycles is higher than the standard. The same work is done to compare standard to realistic operational loads, corresponding to a specific repartition between empty and full car body loads. These results are not presented here, but enable an evaluation of the initial design.

Table 1. Comparison of equivalent and reference number of acceleration cycles on MPL75. Test Standard

Direction

Full load

Empty load

Reference load

Lateral Vertical

9.9 10 4 7.4 10 7

3.1 10 5 5.8 10 6

1 10 7 1 10 7

From strain gauge and GPS measurements, stresses are projected on the network, see Fig. 6. This visualization makes it possible to correlate the stress events and the network localization and specificity (rail default, specific curve, etc). Each line is characterized in terms of damage to the car body. The stress events are also compared to the car body dynamic behavior from accelerometers. Finally, measurement analysis makes it possible to correlate the fatigue behavior, the network and the car body dynamic behavior. From this analysis, network operations can be adapted to reduce the car body fatigue damage.

Fig. 6. Stress map on tramway line T1 for one gauge location.

3.3. Remaining life evaluation and road map From experimental results, the FEM is updated with operating loads and current status characteristics, see Fig.7. From on-line measurements, actual loads are applied on the FE model. The FE model is tuned to correlate simulated stress and accelerations to the measurements. Using the final reliable FEM, the future life of the structure is simulated.