1,720,976 research outputs found
ANN based Approach to the Structural Health Monitoring of a Traction Equipment
No full textThe concept of predictive maintenance, whose application became every day more and more diffused was born some years ago. The fundamental idea on which the predictive maintenance is based on is the monitoring of specific parameters that can supply useful information on the system state of health. In the presented application, vibrational levels represent one of these parameters and relative continuous monitoring is proposed. As a drawback of this approach, the availability of monitoring devices and their correct installation is needed, even if many times not availablr for cost or installation reasons. To avoid such limitations, the present work present an Artificial Neaural Network based approach for the management of “virtual” sensors whose data are derived from a limited set of sub-data. The presented application will show interesting results obtained with reference to a traction converter system as an example of the proposed technique
A numerical study of liquid impact on inclined surfaces
No full textLiquid impact on planar surfaces is a challenging issue in many research fields. Under certain circumstances, these phenomena may occasionally produce high, spatially localized pressure peaks, thus inducing dangerous solicitations. The present work focuses on some relevant computational aspects of the fluid impact onto inclined planar surface, making use of the Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) Lagrangian technique. With reference to the early stages of the impact process, pressure distribution is described as function of the incident wave’s features and the angle of incidence of the solid surface assumed. Results are then discussed and compared with the corresponding ones obtained via Eulerian software
On the Hydraulic Efficiency of Distributed Detention Basins: a Case of Study
No full textThis work presents a computer assisted methodology for designing a distributed system of rainstorm detention basins. The procedure is based on the condition that water discharge must be lower than a fixed threshold limit at the downstream end of the system, for a given input hydrograph flowing over it.
Results were obtained for a portion of the Solofrana brook between Solofra and Pandola municipalities, Campania Region, Southern Italy. Flow rates were first determined for a return period of 100 years by applying the VAPI geomorphoclimatic model. Then, basin volumes were determined on the condition that the maximum discharge had not exceeding the limit of 60m3/s, as imposed by the Hydrogeological Structure Plan (PSAI) of the Central Campania Basin Authority
Optimization for multi-parameter calibration in the numerical analysis of submerged flows for jet grouting
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Optimization for multi-parameter calibration in the numerical analysis of submerged flows for jet grouting
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An Innovative Numerical Modeling Approach for Train Noise Sources Simulation
No full textThe recent growth in the railway sector has involved a fast increment in technologies and requirements. The first trains were slow, noisy and polluting, the modern ones are more comfortable and the electrical engine can guarantee a safe-life for nature. The recent improvement in technology has been pulled by the more strictly requirements imposed by the law and by the customers, especially in terms of safety and comfort criteria. One of the more hard-to-satisfy criteria is the acoustical one. The European Union has recently approved a new technical regulation that must be satisfied for trains: the value of allowable SPL inside the cabin is fixed to 65 dB. This requirements is than generally lowered by the customer requirements that imposes a “technical minimum requirement” more strictly than legislative one. Before the train is available for experimental tests just a numerical approach can be used to forecast the acoustic performance of the system. Many numerical approaches are available in this sense, as those based on Fem, BEM, SEA or Ray Tracing formulations; the availability of new computers and technologies has increased the computational capabilities and increased the accuracy of these tools . In any case, all these approaches can be used only to predict the distribution of noise field (in terms of SPL for example) and/or to identify the relative spectral characteristics; they cannot exactly replicate the subjective response to noise exposure. To reproduce this sensation of sound or noise, during this work, an hybrid approach based upon “standard” numerical technique and novel mathematical approaches have been used . Two train noise sources have been chosen (wheel and engine) and mathematical models have be developed to calculate the SPL vs time relationship. The model, implemented in a Simulink® environment, has been used for a real-time simulation of the source noise emission and relative interaction with the physical environment . The computed noise can be heard using a speaker system
Environmental implications deriving from a renewing of freight vehicles affecting the container terminals: an Italian case study
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