Issue 33

R. Sepe et alii, Frattura ed Integrità Strutturale, 33 (2015) 451-462; DOI: 10.3221/IGF-ESIS.33.50 451 Static and modal numerical analyses for the roof structure of a railway freight refrigerated car Raffaele Sepe Dept. of Chemical, Materials and Production Engineering, University of Naples Federico II P.le V. Tecchio, 80 - 80125 Naples, Italy. raffsepe@unina.it Angela Pozzi Advanced Transports s.r.l., Zona Ind Ex Indesit, - 81030 Gricignano di Aversa, Italy. angela.pozzi@advancedtransports.it A BSTRACT . Numerical analyses by finite element method and experimental tests are used to determine static and dynamic behaviour of railway vehicles. Experimental measurements are very time consuming and expensive, so they cannot be used at all stages of design. Numerical simulations do not have the disadvantages of experimental methods, but it is necessary to verify them by experiments to obtain realistic results. Full- width/full-length, half-width/full-length and half-width/half-length modeling approaches can be used to determine static and vibrational behaviours of railway vehicles depending or not on the symmetry of roof structure and applied load. Different static loading cases defined in standards such as EN 12663, UIC CODE OR 577 and ERRI B12/RP17 have to be considered in FE analyses. Evaluation of stress states, buckling and vibrational behaviours for a roof structure of a railway freight refrigerated car are presented. To highlight the vibrational behaviour of the structure normal mode (free vibration) analyses are performed. As a result of the relevant simulations, structural characteristics and structural weaknesses of the design are determined. K EYWORDS . Railway freight car; Refrigeration system; Finite Element Method (FEM). I NTRODUCTION he railway vehicle must meet a number of requirements, including: safety requirements for crash scenarios, derailment, fire, pressure waves in tunnels, etc. The car body must also be within the specific construction profile of the operated line. It must be strong enough not to fail during typical maximum loads or during cyclic loading. A large amount of these requirements are, for example, covered by the standards EN 12663-1 and EN 12663-2 [1-2]. Static and dynamic tests are performed according to international standards [1-4] during the certification procedures of the railway vehicle before putting it into the service. Experimental measurements are very time consuming and expensive, so they cannot be used at all stages of design. Hence, today numerical methods are important tools in static and dynamic analyses of railway vehicles. In fact, numerical simulations do not have in same amount the aforementioned disadvantages of experimental methods. Finite Element Method (FEM) is a powerful numerical engineering analysis tool, hence widely used in static and dynamic stress analyses of railway vehicles, moreover, it can be used easily for different load cases and in all step of design due to its economy and flexibility. T