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Sliding model of flat die test under the variable contact conditions in the thin sheets deep drawing process

dc.contributor.advisorAleksandrović, Srbislav
dc.contributor.otherVilotić, Dragiša
dc.contributor.otherMandić, Vesna
dc.contributor.otherMitrović, Slobodan
dc.contributor.otherLazić, Vukić
dc.creatorĐorđević, Milan
dc.date.accessioned2018-12-27T12:16:39Z
dc.date.available2018-12-27T12:16:39Z
dc.date.available2020-07-03T15:12:55Z
dc.date.issued2018-09-19
dc.identifier.urihttps://nardus.mpn.gov.rs/handle/123456789/10518
dc.identifier.urihttp://eteze.kg.ac.rs/application/showtheses?thesesId=6139
dc.identifier.urihttps://fedorakg.kg.ac.rs/fedora/get/o:1025/bdef:Content/download
dc.description.abstractABSTRACT: The deep drawing technology has a significant place in the contemporary industry. Intensive development of the automotive industry contributes a lot to that fact. With development of the new materials of the poorer machinability and with increase of the technological requirements to the higher level, the necessity for complete control of the forming process is increasing as well. There are significant difficulties in realizing any action during the process duration. In present conditions, only two possibilities are at hand: the blank holding force of the variable intensity and drawing beads of the variable height. Both actions require complex control systems. Contemporary technological problems in deep drawing of parts of the complex geometry can be successfully studied experimentally by means of the physical modeling. The physical model of the contact between the flat surfaces has the dominant space at the flange during the deep drawing process of thin sheets. The emphasis is on realizing the nonlinear dependencies of the contact pressure during the process, as one of the possibilities for the process control. The forming process is usually realized in such a way that all the process parameters and conditions (the blank holding force, deformation rate, etc.) are being set prior to the sliding path of the machine. The concrete investigation shows what effects are realized due to the variable intensities of the blank holding force during the deep drawing process. In addition, it is important to define the functional dependencies of the blank holding force. The basic idea is setting the variable pressure in the contact during the sliding process and monitoring the drawing force (the friction force), the friction coefficient, surface roughness of the thin sheet and the tool. Three different materials were applied, two types of lubricants and four versions of the tool's contact elements. The conducted investigations were of the theoretically-experimental character with focus on the experimental part. In the first part of investigations, the theoretical analysis and critical considerations of existing results were conducted. Then followed forming of the nonlinear and linear functional dependencies of the simultaneous variation of the blank holding force (contact pressure) during the process, depending on the thin sheet sample's path. The specific feature of the test is realization of the nonlinear and linear functions of the contact pressure variation during the process. In the second part of the dissertation is presented the concept and realization of the complex measuring-controlling device. The original experimental tribological test was designed and realized, based on a physical model of the thin sheets strips sliding between the working surfaces, with the objective to enable realization of predefined functions of the contact pressure (the blank holding force). Based on that, the precise quantification of effects of the concrete influences (type of thin sheets, tool parameters and contact conditions) on the drawing force, friction coefficient and variation of the surface roughness of the thin sheet and the tool, was realized. Knowing the nature of the mentioned effects enables improvement of knowledge about different influences of the deep drawing process and provides the possibility for controlling that process. Systematization of these results, besides the scientific has a significant practical value, especially in the area of the new technologies of the metal plastic forming, particularly in the deep drawing of thin metal sheets.en
dc.description.abstractREZIME: Tehnologija dubokog izvlačenja zauzima značajno mesto u savremenoj industriji. Intenzivan razvoj automobilske industrije tome veoma doprinosi. Razvojem novih materijala lošije obradivosti i povećanjem tehnoloških zahteva na viši nivo, raste potreba za potpunim upravljanjem procesom oblikovanja. Postoje znatne teškoće u ostvarivanju bilo kakvih dejstava dok proces traje. U sadašnjim uslovima to su samo dve mogućnosti: sila držanja promenljivog intenziteta i zatezna rebra promenljive visine. Oba dejstva zahtevaju složene upravljačke sisteme. Savremena tehnološka problematika dubokog izvlačenja delova složene geometrije može se uspešno eksperimentalno izučavati putem fizičkog modeliranja. Fizički model kontakta između ravnih površina zauzima dominantan prostor na obodu komada pri dubokom izvlačenju tankih limova. Jedna od mogućnosti upravljanja procesom je zadavanje nelinearnih zavisnosti kontaktnog pritiska za vreme njegovog trajanja. Proces oblikovanja se najčešće realizuje tako što se svi parametri i uslovi procesa (sila držanja, brzina deformisanja, i dr.) podešavaju pre početka radnog hoda mašine. Konkretno istraživanje pokazuje kakve efekte ostvaruju promenljivi intenziteti sile držanja za vreme procesa dubokog izvlačenja. Takođe, od bitnog značaja je i definisanje funkcionalnih zavisnosti sile držanja. Osnovna ideja je zadavanje promenljivog pritiska u kontaktu za vreme procesa klizanja i praćenje promene vučne sile (sile trenja), koeficijenta trenja, površinske hrapavosti lima i alata. Primenjena su tri različita materijala, dve vrste maziva i četiri varijante kontaktnih elemenata alata. Sprovedena istraživanja su teorijsko-eksperimentalnog karaktera s težištem na eksperimentu. U prvom delu istraživanja izvodi se teorijska analiza i kritičko sagledavanje dosadašnjih rezultata. Zatim sledi formiranje nelinearnih i linearnih funkcionalnih zavisnosti simultane promene sile držanja (kontaktnog pritiska) tokom procesa, zavisno od hoda uzorka lima. Osobenost testa je ostvarivanje linearnih i nelinearnih funkcija promene kontaktnog pritiska za vreme trajanja procesa. U drugom delu rada, izlaže se koncepcija i realizacija složenog merno-upravljačkog uređaja. Projektovan je i realizovan originalni eksperimentalni tribološki test zasnovan na fizičkom modelu klizanja traka lima između ravnih površina, čiji je cilj da omogući ostvarivanje prethodno definisanih funkcija kontaktnog pritiska (sile držanja). Na osnovu toga izvršeno je precizno kvantifikovanje efekata konkretnih uticaja (vrste lima, parametara alata i kontaktnih uslova) na vučnu silu, koeficijent trenja i promene hrapavosti površina lima i alata. Poznavanje prirode navedenih efekata omogućava unapređenje znanja o uticajima na tok procesa dubokog izvlačenja, i daje mogućnosti za upravljanje tim procesom. Sistematizacija ovih rezultata, pored naučne, ima i značajnu praktičnu vrednost u oblasti novih tehnologija plastičnog oblikovanja metala, posebno u oblasti dubokog izvlačenja tankih limova.sr
dc.formatapplication/pdf
dc.languagesr
dc.publisherУниверзитет у Крагујевцу, Факултет инжењерских наукаsr
dc.relationinfo:eu-repo/grantAgreement/MESTD/Technological Development (TD or TR)/34002/RS//
dc.rightsopenAccessen
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.sourceУниверзитет у Крагујевцуsr
dc.subjectdeep drawingsr
dc.subjectduboko izvlačenjeen
dc.subjectklizanje trake limaen
dc.subjectravne kontaktne površineen
dc.subjectkontaktni pritisaken
dc.subjectpromenljivi kontaktni uslovien
dc.subjectupravljanje procesomen
dc.subjectflat die testsr
dc.subjectthin sheet strip slidingsr
dc.subjectcontact pressuresr
dc.subjectvariable contact conditionssr
dc.subjectprocess controlsr
dc.titleModel klizanja između ravnih površina oboda pri promenljivim kontaktnim uslovima u procesu dubokog izvlačenja tankih limovasr
dc.title.alternativeSliding model of flat die test under the variable contact conditions in the thin sheets deep drawing processen
dc.typedoctoralThesisen
dc.rights.licenseBY-NC-ND
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/48223/Milan_DJordjevic_FIN.pdf
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/48222/Disertacija.pdf
dc.identifier.fulltexthttps://nardus.mpn.gov.rs/bitstream/id/48223/Milan_DJordjevic_FIN.pdf
dc.identifier.fulltexthttps://nardus.mpn.gov.rs/bitstream/id/48222/Disertacija.pdf
dc.identifier.rcubhttps://hdl.handle.net/21.15107/rcub_nardus_10518


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