Search results for " bearing"

showing 10 items of 52 documents

MULTIBODY NUMERICAL SIMULATION OF AN INTERNAL COMBUSTION ENGINE WITH APPRAISAL OF THE WEAR DAMAGE

2009

An internal combustion engine at four times (Otto cycle) and three cylinders is simulated by multibody software MSC Visual Nastran. The bearings are simulated by means of the library of constraint of the software, putting a particular attention to bench bearings and to the lubrication conditions. The loads on the bench bearings and in both the feet and head of the connecting rods, are evaluated by dynamical simulation, so that the inertia loads can be take in account, considering the condition of the maximum couple furnished by the engine. By making the necessary hypothesis, the evaluation of the wear damage is executed by Bayer theory on zero wear, obtaining that a good expectation of life…

Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di MacchineZero Wear Bearings Multibody simulation
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DYNAMIC BEHAVIOUR COMPARISON OF ROTATING SHAFT SUSPENDED BY TWO RADIAL ACTIVE MAGNETIC BEARINGS.

2012

Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di Macchineactive magnetic bearings.Dynamic behaviour comparisonrotating shaft suspended
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EXPERIMENTAL INVESTIGATIONS OF MINIMUM POWER CONSUMPTION OPTIMAL CONTROL FOR VARIABLE SPEED AMB ROTOR

2010

The purpose of this paper is to present a method for development of the optimal speed-dependent control matrix for a rotor supported on active magnetic bearings (AMBs) with the provision of minimum control power consumption over the operating speed range. The speed dependency of the optimal control matrix is the result of the dynamics of rotating machines. Most of published works on optimal control use a stationary optimal control matrix derived for the non-rotating system and thus neglecting the effect of gyroscopic phenomena. This paper employs the minimum energy consumption condition to derive the speed varying optimal control for rotating AMB rotor system. In the presented approach the …

Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di Macchineoptimal control active magnetic bearing speed varying
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Deficit irrigation does not affect alternate bearing of ‘Valencia’ orange trees

2018

This study evaluated the effect of long-term partial rootzone drying and continuous deficit irrigation on the degree of alternate bearing of adult ‘Valencia’ orange trees grown in northern Sicily. Three irrigation strategies were imposed in summer from 2007 to 2011: irrigation with volumes corresponding to 100% of crop evapotranspiration applied to entire rootzone (CI), partial rootzone drying (PRD) with 50% of CI water applied to one alternated side of the rootzone, and continuous deficit irrigation (CDI) with 50% of CI water applied to both sides of the rootzone. The experiment was conducted on 48 adult orange trees arranged according to a randomized block design. Weather and soil paramet…

Stomatal conductanceBearing (mechanical)Fruit yieldDeficit irrigationBiennial bearingRelative water contentStomatal conductanceBiologyHorticultureAffect (psychology)Valencia orangeBiennial bearingfood.foodlaw.inventionSettore AGR/03 - Arboricoltura Generale E Coltivazioni ArboreeHorticulturefoodlawPartial rootzone drying
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Active magnetic bearing design study

2012

The purpose of this paper is to propose a useful method to implement active magnetic bearings (AMBs) on an existing rotating shaft which rotates on conventional bearings. This is feasible if AMBs can produce the same reaction loads of conventional ones and if the size of vane is large enough to host an AMB. As this substitution could offer some difficulties due to the different size between magnetic bearings and conventional ones, a set of equations are performed to show that a variation of some parameters can solve this problem. The journal ratio is the geometrical parameter introduced to develop the present analysis. The variation of journal ratio does not produce a variation of the pole…

Surface (mathematics)Engineeringbusiness.industryRotor (electric)Active magnetic bearing journal ratio magnetic field rotorMechanical EngineeringNumerical analysisAerospace EngineeringMagnetic bearingMagnetic fieldlaw.inventionDynamic simulationSet (abstract data type)Settore ING-IND/14 - Progettazione Meccanica E Costruzione Di MacchineMechanics of MaterialsControl theorylawAutomotive EngineeringGeneral Materials SciencebusinessHost (network)Journal of Vibration and Control
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La scoperta, sistemazione e conservazione della grande Iscrizione di Gortina, nell'isola di Creta (1884-1921): la protezione delle testimonianze e le…

2013

La scoperta e la conservazione della Grande Iscrizione di Gortina a Creta, da parte degli studiosi italiani, fra la fine del XIX sec. e i primi decenni del XX sec., rappresentò un grande riconoscimento scientifico-culturale per la giovane nazione italiana. Nel passato, l’isola di Creta era stata legata alla Repubblica di Venezia e anche questo rapporto favorì l’invio a Creta del giovane epigrafista F. Halbherr, il quale fra notevoli peripezie rinvenne, assieme all’epigrafista tedesco E. Fabricius, la famosa l’iscrizione nell’antica città di Gortina. L’iscrizione, fra le più antiche e complete finora conosciute in tutta Europa, conteneva le norme sulla famiglia, l’eredità e in generale i dir…

The discovery and preservation of the Great Inscription of Gortyna in Crete by Italian researchers in the late nineteenth century. and the first decades of the twentieth century. was an important cultural and scientific recognition for the young Italian nation. In the past the island of Crete had been tied to the Republic of Venice and this report also favored sending in Crete the young epigraphist F. Halbherr who among considerable vicissitudes came to together to the epigraphist german E. Fabricius the inclusion of the famous ancient city of Gortyna. The inscription among the oldest and most comprehensive so far known throughout Europe the rules contained on the family's legacy in general and the rights and duties of some of the people of the Minoan civilization (480-450 BC). The inscription was carved on blocks organic limestone a restored ancient building which later in Roman times was turned into odeon. The Laws of Gortyn were engraved on the remains of the wall forming the passageway in front of the steps of the odeon. The essay traces the events that led to the discovery and subsequent storage made by Halbherr especially with the help of archaeologist L. Pernier and finally with the help of architect E. Stefani who designed a modern cover on the top of the ambulatory of the segments containing the inscription. This coverage was made to perform during the First World War on the basis of the Italian project from the Greek Government in order to protect the membership from possible war damage but especially from vandalism. The roof brick clay of the Laws of Gortyna still serves its function and ensures the use of the monument bearing witness to the preservation of Italian culture in Greece and more generally in the world. But in Sicily in the remains of the Villa del Casale in Piazza Armerina (Enna) its elegant protection (built in 1957) is representative of a whole period of culture of the Italian restoration is removed and replaced because it has not been able to make a ongoing maintenance is due. A bad example of conservation and management of a UNESCO monument from which arise after the work for the construction of new roofs an equally insulting to the archaeological heritage and scenic Italian and world.Settore ICAR/19 - Restauro
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Steel Fibres: Effective Way to Prevent Failure of the Concrete Bonded with FRP Sheets

2016

Although the efficiency of steel fibres for improving mechanical properties (cracking resistance and failure toughness) of the concrete has been broadly discussed in the literature, the number of studies dedicated to the fibre effect on structural behaviour of the externally bonded elements is limited. This experimental study investigates the influence of steel fibres on the failure character of concrete elements strengthened with external carbon fibre reinforced polymer sheets. The elements were subjected to different loading conditions. The test data of four ties and eight beams are presented. Different materials were used for the internal bar reinforcement: in addition to the conventiona…

chemistry.chemical_classificationToughnessMaterials scienceArticle SubjectBar (music)Glass fiber0211 other engineering and technologiesGeneral Engineering020101 civil engineering02 engineering and technologyPolymerFibre-reinforced plasticLoad bearing0201 civil engineeringCrackingchemistry021105 building & constructionlcsh:TA401-492lcsh:Materials of engineering and construction. Mechanics of materialsGeneral Materials ScienceComposite materialReinforcementAdvances in Materials Science and Engineering
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Bearing fault detection based on time-frequency representations of vibration signals

2015

To prevent failures of a rolling bearing in the gearbox drive system, acceleration sensors are used to detect fault-related signals of the bearing. It is a big challenge to observe and identify signals caused by bearing defects in the time domain or the frequency spectrum by a conventional Fourier analysis. The time-frequency representation of the fault-related signals implemented by the windowed Fourier transform is studied in this work. It is shown that the fault characteristic frequencies can be clearly identified in the time-frequency spectrum if a fault occurs in the bearing of the gearbox at different speeds. Otherwise, the shaft frequency and its multiples are the main harmonics in t…

gearbox drive trainEngineeringaccelerometersBearing (mechanical)business.industryMechanical EngineeringAcousticswindowed Fourier transformEnergy Engineering and Power Technologyaccelerometers; bearing faults; gearbox drive train; windowed Fourier transform; Energy Engineering and Power Technology; Electrical and Electronic Engineering; Mechanical EngineeringFault (power engineering)Fault detection and isolationlaw.inventionTime–frequency analysisVibrationsymbols.namesakeFourier transformFourier analysislawsymbolsElectronic engineeringbearing faultsTime domainElectrical and Electronic Engineeringbusiness2015 18th International Conference on Electrical Machines and Systems (ICEMS)
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Solai ad orditura metallica. Per una storia della costruzione

2016

Sommario: Il saggio approfondisce gli aspetti storici e costruttivi dei solai ad orditura metallica dalla fine del XVIII secolo all’ultima guerra. Dopo una parte generale in cui vengono delineate le motivazioni e le fasi iniziali dell’uso dei materiali ferrosi in edilizia, si traccia ed analizza una serie di linee evolutive della trave metallica, fino al raggiungimento della sezione a doppio T che, a pieno titolo, si considera il punto di arrivo della ricerca sulla forma più conveniente per evidenti motivi di efficienza statica, pur coi successivi affinamenti nella produzione, nel calcolo e nella messa in opera. Si è ipotizzata l’evoluzione attraverso le strade della combinazione legno-ferr…

iron cast iron historic construction floor bearing structureSettore ICAR/10 - Architettura Tecnicasolai orditura ferro ghisa costruzione storica
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Assessment of paradoxical anterior translation in a CR total knee prosthesis coupling dynamic RSA and FE techniques

2021

Purpose: The study aims were to assess the kinematic data, Internal-External (IE) rotation, and Antero-Posterior (AP) translation of the contact points between the femoral condyles and polyethylene insert and to develop a combined dynamic RSA-FE (Radiostereometric – Finite Element) model that gives results congruent with the literature. Methods: A cohort of 15 patients who underwent cemented cruciate-retaining highly congruent mobile-bearing total knee arthroplasty were analyzed during a sit-to-stand motor task. The kinematical data from Dynamic RSA were used as input for a patient-specific FE model to calculate condylar contact points between the femoral component and polyethylene insert. …

medicine.medical_specialtyKinematicsmedicine.medical_treatmentKinematicsRotationTranslation (geometry)ProsthesisCondyleTotal knee03 medical and health sciences0302 clinical medicineMobile bearingmedicineCoupling (piping)Orthopedics and Sports MedicineARTHROPLASTYMathematicsTKA FEATURESOrthodonticsOrthopedic surgery030222 orthopedicsOriginal PaperScience & TechnologyTKAGénéralités030229 sport sciencesDynamic RSAKinematicOrthopedicsOrthopedic surgerySurgeryFE analysiFE analysisLife Sciences & BiomedicineRD701-811
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