a b s t r a c tIn railway applications, the estimation of wear at the wheel-rail interface is an important field of study, mainly correlated to the planning of maintenance interventions, vehicle stability and the possibility of carrying out specific strategies for the wheel profile optimization. In this work the authors present a model for the evaluation of wheel and rail profile evolution due to wear specifically developed for complex railway networks. The model layout is made up of two mutually interactive but separate units: a vehicle model (composed of the multibody model and the global contact model) for the dynamical analysis and a model for the wear evaluation (composed of the local contact model, the wear evaluation procedure and the profile update strategy).The authors propose a statistical approach for the railway track description to study complex railway lines in order to achieve general significant accuracy results in a reasonable time: in fact the exhaustive simulation of the vehicle dynamics and of wear evolution on all the railway network turn out to be too expensive in terms of computational effort for each practical purpose.The wear model has been validated in collaboration with Trenitalia S.P.A and RFI, which have provided the technical documentation and the experimental data relating to some tests performed on a scenario that exhibits serious problems in terms of wear: the vehicle ALn 501 "Minuetto" circulating on the Aosta-Pre Saint Didier Italian line.

The objective of this work is the development of an innovative actuator for Velan ABV S.p.A., which is mainly used for control and special on/off applications where high efficiency and linear behaviors are desirable specifications. The main performances of the proposed actuator, which has been protected by a patent, have been compared with a conventional scotch yoke one, using both the simulation results and the experimental data. In order to measure the efficiency and the dynamical response of the actuators, the authors have designed a hydraulic test rig, configured to fulfill different testing procedures. In this way, it is possible to perform both static tests to identify actuator efficiency and dynamic hardwarein-the-loop tests in which an assigned load or valve impedance function is simulated to verify the response of the tested object in realistic operating conditions. Finally, the proposed test rig has been successfully used to perform reliability and fatigue tests in which the actuator is stressed with realistic and repetitive loads. Moreover, the integrated development of both innovative actuator and testing devices is explained introducing interesting concepts whose applications are normally limited to robotics (e.g. impedance and force control) or vehicular technology (e.g. smart suspensions and suppression of vibrations).

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The accurate model of the complicated dynamic phenomena characterizing rotors and support structure represents a critical issue in the rotor dynamic field. A correct prediction of the whole system behavior is fundamental to identify safe operating conditions and to avoid instability operating range that may lead to erroneous project solutions or possible unwanted consequences for the plant. Although a generic rotating machinery is mainly composed by four components (rotors, bearings, stator and supporting structure), many research activities are often more focused on the single components rather than on the whole system. The importance of a combined analysis of rotors and elastic supporting structures arises with the continuous development of turbomachinery applications, in particular in the Oil and Gas field where a wide variety of solutions, such as off-shore installations or modularized turbo-compression and turbo-generator trains, requires a more complete analysis not only limited to the rotor-bearing system. Complex elastic systems such as rotating machinery supporting structures and steel foundations might, in some situations, strongly dominate the entire shaft line rotor dynamic response (mode shapes, resonance frequencies and unbalance response). They give birth to transfer functions which will introduce coupling phenomena between machines bearings, becoming enablers of a new shaft line dynamic. Since FEM theory offers a number of different solutions to represent the rotor and the rotating machine support system (beam models, solid models, transfer function, etc.), in this paper a great emphasis is given to the results of an experimental campaign done on a centrifugal compressor as validation of the new rotor dynamic approach.