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Influential parameters of articulated segments on elastic-dynamic stability of truck crane booms

dc.contributor.advisorGašić, Milomir
dc.contributor.otherVladić, Jovan
dc.contributor.otherJanošević, Dragoslav
dc.contributor.otherSavković, Mile
dc.contributor.otherPetrović, Dragan
dc.creatorZdravković, Nebojša B.
dc.date.accessioned2016-01-05T13:08:07Z
dc.date.available2016-01-05T13:08:07Z
dc.date.available2020-07-03T15:10:52Z
dc.date.issued2015-06-19
dc.identifier.urihttp://nardus.mpn.gov.rs/handle/123456789/3646
dc.identifier.urihttp://eteze.kg.ac.rs/application/showtheses?thesesId=2077
dc.identifier.urihttps://fedorakg.kg.ac.rs/fedora/get/o:503/bdef:Content/download
dc.description.abstractAuto-dizalice imaju jednu od ključnih uloga tokom izgradnje i održavanja svih vidova stambene, saobraćajne i industrijske infrastrukture. Česte promene lokacije utovara i istovara, manipulacija raznovrsnim teretom u uslovima ograničenog manevarskog prostora, povećanje nosivosti, visine dizanja i dohvata, operativna bezbednost i stabilnost, ergonomsko i efikasno upravljanje, uz visok stepen iskorišćenja energije formiraju kompleksan skup suprotstavljenih zahteva i ograničenja pri njihovom projektovanju. U cilju dobijanja lakših, energetski efikasnijih i ekonomičnijih rešenja, inženjeri su primorani da optimizuju noseću strukturu strela auto-dizalica. Direktna posledica ove tendencije je povećanje elastičnosti i pojava oscilacija, koje nepovoljno utiču na radni vek strele usled pojave zamora i otežavaju upravljanje dizalicom. U radu je prezentovan kombinovani pristup modeliranju dinamičkog ponašanja zglobno vezanih segmenata strele, pri savojnim oscilacijama, na primeru jedne realne konstrukcije, sastavljene od dva segmenta i hidrocilindra sa vešajnim sklopovima. Segmenti strele su tretirani kao Euler-Bernoulli-jeve grede sa distribuiranim inercijalnim i elastičnim parametrima, dok je zbirni uticaj hidrocilindra i vešajnih podsklopova uzet u obzir preko koncentrisanih masa u vešajnim tačkama. Takođe, pri definisanju modela uzeta je u obzir aksijalna krutost samog hidrocilindra. Masa tereta je koncentrisana u krajnjoj tački fleksibilnog manipulatora. S obzirom da šasija vučnog vozila nije apsolutno kruta, elastičnost oslanjanja je ugrađena u model preko opruge u osloncu. Posebna pažnja je posvećena konstruktivnoj specifičnosti strela auto-dizalica koja se tiče ekscentričnosti vešajnih tačaka hidrocilindra u odnosu na neutralne linije segmenata. Veza hidrocilindra i segmenata je modelirana specijalnim sistemom lakih, aksijalno krutih štapova. Kao generalisane koordinate slobodnih savojnih oscilacija usvojena su poprečna pomeranja ekvidistantnih tačaka duž neutralnih linija. Uspostavljena je analitička zavisnost sile u hidrocilindru u funkciji transverzalnih pomeranja karakterističnih tačaka na segmentima, čije su aksijalne deformacije zanemarene. Cela zglobna struktura je izdeljena na sekcije tačkama u kojima deluju transverzalne sile. Diferencijalni oblici dinamičkih elastičnih linija sekcija i graničnih uslova su diskretizovani metodom centralnih konačnih razlika. Granični problem je transformisan u sistem lineranih algebarskih jednačina, pogodan za programiranje. Tačnost dobijenih zavisnosti elasto-dinamičkih parametara strukture je potvrđena poređenjem prirodnih učestanosti predloženog modela sa rezultatima iz modela izgrađenog na bazi metode konačnih elemenata, za sve geometrijske konfiguracije zglobnog manipulatora. Problem promenljivosti poprečnih preseka segmenata je obuhvaćen posebnim poglavljem. Korišćenjem istog pristupa, izvršena je i frekventna analiza teleskopskog dela strele.sr
dc.description.abstractTruck cranes have one of key roles in construction and maintenance of all kinds of residential, traffic and industrial infrastructure. Frequent changes in loading and unloading locations, manipulation with different loads in conditions of restricted maneuver space, capacity increase, lifting height and reach increase, operating safety and stability, ergonomic and efficient control, with high degree of energy utilization, create a complex set of opposing demands and restrictions in their design. In order to get the lightweight, energetically more efficient and economical solutions, the engineers are forced to optimize the carrying structure of truck crane booms. Direct effect of this tendency is the increase of elasticity and the occurrence of vibrations which unfavorably affect the boom’s life due to fatigue and make the crane control difficult. In this research, a combined approach to modeling of dynamic behaviour of boom articulated segments in bending vibration is presented, in the case of a real-life structure which consists of two segments, hydro cylinder and mounting subassemblies. Segments of the boom are considered as Euler-Bernoulli’s beams with distributed inertial and elastic parameters, while the total influence of hydro cylinders and mounting subassemblies has been taken into account through lumped masses in mounting points. Given that the towing vehicle’s chassis is not absolutely rigid, the boom support elasticity has been built in the model through the spring in the support. Special attention has been given to the constructive specificity of truck cranes’ booms which deals with the eccentricity of hydro cylinders’ mounting points in relation to segments’ neutral lines. Bond of hydro-cylinders and segments has been modeled by a special system of light, axially rigid rods. As generalized coordinates of free bending vibrations there have been adopted the transverse displacements of equidistant points along the neutral lines. There has been established the analytic dependence of the force in hydro-cylinder in terms of transverse displacements of characteristic points on segments, whose axial deformations are neglected. Whole articulated structure is divided in sections by points where transverse forces act. Differential forms of sections’ dynamic elastic lines and boundary conditions are discretized by central finite difference method. Boundary problem is transformed into a system of linear algebraic equations, suitable for programming. Accuracy of obtained dependencies of elasticdynamic structure parameters is confirmed by comparing the natural frequencies of proposed model with results from the model built on the base of finite element method, for all geometrical configurations of articulated manipulator. The problem of segments’ crosssections non-uniformity is covered in special chapter. By using the same approach, there has been also carried out the frequency analysis of telescopic part of the boom.en
dc.formatapplication/pdf
dc.languagesr
dc.publisherУниверзитет у Крагујевцу, Факултет за машинство и грађевинарство, Краљевоsr
dc.relationinfo:eu-repo/grantAgreement/MESTD/Technological Development (TD or TR)/35038/RS//
dc.rightsopenAccessen
dc.sourceУниверзитет у Крагујевцуsr
dc.subjectfleksibilni manipulatorisr
dc.subjecttruck cranesen
dc.subjectarticulated boomsen
dc.subjectflexible manipulatorsen
dc.subjectbending vibrationsen
dc.subjectEuler-Bernoulli’s beam theoryen
dc.subjectcentral finite difference methoden
dc.subjectnatural frequenciesen
dc.subjectfinite element methoden
dc.subjectsavojne oscilacijesr
dc.subjectEuler-Bernoulli-jeva teorija gredasr
dc.subjectmetoda centralnih konačnih razlikasr
dc.subjectprirodne učestanostisr
dc.subjectmetoda konačnih elemenatasr
dc.titleUticajni parametri zglobno vezanih segmenata na elasto-dinamičku stabilnost strela auto-dizalicasr
dc.titleInfluential parameters of articulated segments on elastic-dynamic stability of truck crane boomsen
dc.typedoctoralThesis
dc.rights.licenseBY-NC-ND
dcterms.abstractГашић, Миломир; Владић, Јован; Савковић, Миле; Јаношевић, Драгослав; Петровић, Драган; Здравковић, Небојша Б.; Утицајни параметри зглобно везаних сегмената на еласто-динамичку стабилност стрела ауто-дизалица; Утицајни параметри зглобно везаних сегмената на еласто-динамичку стабилност стрела ауто-дизалица;
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/47844/Disertacija.pdf
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/47845/nebojsa_zdravkovic_21.04.2015.pdf


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