PSI - Issue 19

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

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3. Case study: Car body This approach has been applied by VibraTec on different railway structures like bogies, car bodies, infrastructure components, etc. In this publication, the approach is presented on a concrete car body case. This analysis was done in collaboration with the Lyon transport organization authority Sytral on two rolling stocks: tramway CITADIS and metro MPL75, respectively 15 years old and 40 years old at the study time. Rolling stock maintenance, renovation and/or replacement costs are major issues for their owners. Indeed, remaining life studies are essential to make the right decisions in terms of sustainable development and investment for rolling stocks owners. As described previously, the approach presented for evaluating remaining life is based on a coupled digital and experimental fatigue analysis. First, the current status of car body’s structural mechanical integrity is studied to quantify the relevance of the manufacturing and the initial design. Then, operational measurements are performed to identify the real operational load, to evaluate and tune the FEM. Using the final reliable FEM, the future life of the structure is simulated. Finally, different operation road maps and modifications can be evaluated to ensure the structural durability and extend asset service life. 3.1. Current status The expertise of the car body’s mechanical integrity is based on complementary use of simulation and examination control. A FE model of the car body is built and then standard loads from EN 12 663 (2015) are applied, see §3.1.1. From this FE analysis, sensitive areas are determined and make it possible to focus the examination control on these areas, see §3.1.2. 3.1.1. FE Simulation The FE model is built from paper plans or 3D if available. The modelling approach is based on VibraTec experience. The mechanical structure is modelled, and non-structural elements (covering, equipment, etc) are considered as mass and inertia at center of gravity. The mesh size is defined to be fine enough to compute the stress in sensitive areas like welding areas. All the connections are modelled to represent the mechanical behavior. Mass balance of the model is updated using actual mass of the system. The modelling is done using NX 11 Siemens software and the computation is done with NX Nastran solver. FE models of MPL 75 and CITADIS are presented in Fig. 2.

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Fig. 2. (a) MPL75 FE model; (b) Citadis FE model.