4,485 research outputs found
The Magnetoelastic Contribution to the Steel Internal Damping
No full textIn this paper, the steel internal damping due to both the thermoelastic and the magnetoelastic phenomena has been investigated through a formulation based on thermodynamical potential joints with a hysteretic damping model. With the aim of focusing on the temperature transient in the solid, a first configuration has been considered, which is characterized by a steel rod with an imposed alternating pure shear strain in which only the thermoelastic contribution was studied. The magnetoelastic contribution was then introduced in a further configuration, in which a steel rod in free motion was subjected to torsion on its ends in the presence of a constant magnetic field. A quantitative assessment of the influence of the magnetoelastic dissipation in steel has been computed according to the Sablik-Jiles model by giving a comparison between the thermoelastic and the prevailing magnetoelastic damping coefficients
Constitutive equations to correlate uniaxial creep behaviour vs stress and temperature for inconel 718
No full textThe paper presents uniaxial creep tests conducted on Inconel 718 superalloy, reporting and describing the results obtained. The creep strain curves have been examined in different scenarios: by varying the initial applied stress, by varying the initial test temperature, and by considering the orientation of the specimens with respect to the direction of the material processing. Finally, ductility and deformation accumulation rate have been evaluated to highlight the effect of the precipitation anisotropy on the creep behaviour. Given the complexity of the creep phenomenon, each phase of the creep strain curves of Inconel 718 has been analysed independently, using constitutive models taken from the literature that allow to describe the phenomenon in pure metals and in some alloys
La concessione abusiva di credito bancario alla luce delle più recenti pronunce della Corte di Cassazione: i principi sanciti nell’ordinanza n. 1387/2023
No full textCon l’ordinanza n. 1387 del 18 gennaio 2923, la Corte di Cassazione è tornata
nuovamente a pronunciarsi in materia di abusiva concessione del credito alle imprese
confermando la responsabilità risarcitoria della banca per aver protratto lo stato deficitario
di una società tramite un illecito sostegno finanziario
Respingente ferroviario
No full textLa presente invenzione si riferisce ad un respingente ferroviario (1) comprendente:
- un corpo fisso (2) destinato ad essere collegato in maniera fissa ad un convoglio ferroviario o ad un vagone ferroviario;
- un corpo mobile (3), mobile in maniera scorrevole rispetto al corpo fisso (2) secondo una direzione di traslazione (T) tra una posizione protratta ed una posizione ritratta;
- uno o più organi elastici (7) agenti tra il corpo fisso (2) ed il corpo mobile (3), configurati in modo tale da sollecitare il corpo mobile (3) verso la sua posizione protratta.
Il respingente ferroviario (1) è almeno parzialmente riempito con una schiuma metallica (10)
Experimental evaluation of tooth-root bending strains of a sun gear in a planetary gear set for off-highway axles
No full textCompliances under load and manufacturing inaccuracies of components in planetary gear sets may affect the pressure distribution on gears teeth, resulting into a significant reduction of the service life. In this work, the pressure distribution on the tooth width of a sun gear in a final drive of an off-highway axle, was evaluated by strain gauges measurements along the tooth root during a bench test of the complete axle. Tests were performed with several planet carriers to assess the effect of different manufacturing errors introduced during the assembly process. Measured data were compared with the results of a theoretical model of the final drive
Il value for money nei processi POG. Profili applicativi e prospettive future
No full textNella distribuzione assicurativa il principio del value for money è finalizzato a identificare se i costi ed i caricamenti del prodotto sono proporzionati ai relativi benefici offerti al target market, nonché ragionevoli tenendo in considerazione le spese sostenute dal produttore, allo scopo di verificare se il prodotto offra o meno valore al target market a cui è diretto in modo da evitare il c.d. value for money risk. Tramite un’attenta analisi della disciplina dettata sul punto da EIOPA, lo scritto si propone di mostrare la declinazione di tale regola all’interno dei processi POG, mettendone in evidenza gli aspetti più importanti e facendo delle riflessioni su quelli che potrebbero essere gli sviluppi operativi futuri della regola, anche sulla base di alcune indicazioni recenti provenienti dall’Autorità di vigilanza nazionale (IVASS)
Evaluation of Toughness Characteristics of a Die-cast Mg-Al-Mn Alloy AM60B Under Different Microstructural Conditions
No full textThe fracture toughness characteristics ofAM60Bdie-casting Mg–Al–Mn high purity alloy are reported. The material, combining rather good ductility, casting properties, and corrosion resistance, is used for manufacturing large thin-section components for the automotive industry.
Center-cracked tension specimens of a thickness of 2.2–3.1mm were machined directly from components produced on large scale and were tested both in as-die-cast and in aged (heat treated for 18 h at 175 ◦C) conditions, monitoring stable crack propagation under increasing applied
load. Crack growth resistance curves (R-curves) were obtained, and the stress intensity factor leading to unstable crack propagation was found
to be about 20MPam1/2 for the as-die-cast material and about 19MPam1/2 for the aged alloy
Effect of collector deformable modes in pantograph–catenary dynamic interaction
No full textThe aim of the paper is to highlight the influence of the deformable modes of the collector of high-speed pantograph on the quality of current collection. The study was first conducted with an experimental survey on a few collectors for high-speed pantographs, in order to determine their modal parameters and dynamic responses in relation with their structures. Subsequently, a comparison with finite-element modelling was performed, comparing the calculated natural frequencies and mode shapes with the measured ones. Finally, the influence of the deformable modes on the dynamic interaction between pantograph and catenary was analysed, using a simulation model developed in previous works, incorporating the deformable modes of the collector into the model of the pantograph, by means of the experimentally defined modal parameters. The objective of this analysis was to investigate, in particular, the effect of the contact wire irregularity on the contact force up to 100 Hz
Analysis of the failure of a tramcar pantograph component through combined experimental approaches
No full textTramcar vehicles collect the required electrical power from the overhead contact line by means of a pantograph that carries a pan head with collector strips in sliding contact with the contact wire. Therefore, any failure of pantograph or of its components has a direct effect on the correct tramcar operation. The paper deals with a case of unexpected failures occurred on a connection element of the articulated frame of the pantograph of tramcars, causing the interruption of the service. No evidence of impact with the overhead line was detected, only it was clear that the immediate cause was the fatigue failure of a pin of the articulated connection between the upper and the lower arms of the frame of the pantograph. To clarify the original cause of the fatigue failure, an approach combining field measurements, laboratory tests and data processing to obtain the stresses acting on the pantograph failed components under service condition was adopted. It was found that the pantograph was subjected to high level of vibrations coming from the vehicle carbody, mainly due to the track irregularity. A comparative failure analysis was carried out and a solution to upgrade the component subjected to failure was proposed and implemented
- …
