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- A validated railway vehicle interior layout with multibody dummies and finite element seats models for crash analysisPublication . Ambrosio, Jorge; Carvalho, Marta; Milho, João; Escalante, Susana; Martin, RobertoWe propose a methodology for the validation of a numerical model of a railway interior with an inline seating layout arrangement, based on the use of multibody and finite element approaches for the analysis of the passive safety. We model the railway interior layout using a nonlinear finite element model of the passenger seats and all supporting structures. Multibody models of test dummies, appropriate to the identification of the injury mechanisms, are used as measuring tools of the human exposure to injury. The crash scenario model uses a crash pulse, which is the surrogate for the impact of the railway vehicle structure. Being the multibody dummy validated independently by the software vendor and the nonlinear finite element structural models built with detailed data, the validation of the complete layout involves the identification of the uncertain parameters used in the scenario construction and not of the parameters used in the independent models already validated. The interaction between the multibody and finite element is represented via a penalty contact force model, which, together with the dummy positioning data, provides the uncertain parameter set used in the validation process. An experimental test of the inline seating layout, carried with a physical prototype, provides the reference dynamic response for the validation of the numerical model. The injury levels measured with the dummies provide the reference injury criteria values used in the validation process. Following the model validation, we discuss the results obtained for the nominal crash scenario in the framework of the most relevant injury indices for railway passenger passive safety.
- Validation of a railway inline seating model for occupants injury biomechanicsPublication . Carvalho, Marta; Martins, Ana Alexandra; Milho, JoãoThis paper presents the validation of a finite element model in LS-DYNA of the interior inline seating layout simulating a frontal rail impact event for which the experimental test results provide the reference for the injury biomechanics of the occupants. The representative layout consists in two rows of seats and its supporting structures modelled with nonlinear finite elements and the crash acceleration pulse that represents the impact of the railway vehicle structure is imposed in the floor of the coach. For the appropriate identification of the injury mechanisms to the occupant associated to the frontal crash analysis is used the Hybrid III 50th percentile Anthropomorphic Testing Device, being the interaction between the occupant model and the structure characterised via penalty contact force models. The validity of the numerical model is discussed to ensure the representativeness of the analysis procedure and to identify the most relevant injury indices of the occupants. In particular, the head injury criterion is the most critical injury index for the inline seating layout, with a relative deviation of 6.2% of the simulation result with respect to the experimental test.