THE WELDING TECHNOLOGY INFLUENCE ON THE DOUBLE T GIRDER BEAMS BUCKLING

Autor/autori: dr. ing. Ioan-Sorin LEOVEANU, Assoc. prof. eng. Eva KORMANÍKOVÁ, PhD (Slovacia), Assis. prof. Eng. Kamila Kotrasová, PhD (Slovacia), Prep. drd. eng. Daniel TAUS

Rezumat: In domeniul ingineriei civile structurile de rezistenta metalice au o deosebita importanta in reducerea greutatii constructiei cu deosebire in cazul constructiilor inalte, a podurilor si a constructiilor cu scop industrial. Pentru a putea micsora cat mai mult greutatea structurilor metalice acestea sunt proiectate in domeniul elasto-plastic ceea ce face ca instabilitatile locale si cele globale sa devina de o importanta covarsitoare. De mare actualitate in prezent, dar cu precadere pentru structurile viitoare, tehnologia de sudura prin marea sa flxibilitate constitue una dintre optiunile cele mai atragatoare optiuni de realizare a geometriei sectiunilor grinzilor si stalpilor acestora. In lucrarea prezenta colectivul de autori cauta sa gaseasca o legatura cat mai stransa intre tehnologia de sudura si cerintele privind comportarea la flambaj a stalpilor, cerinte impuse in diversele standarde de proiectare. Deoarece tehnologia de sudura necesita cunostinte in diverse domenii ale stiintei, modelarea campului termic in regimul de topire si curgere a metalului topit, stiinta materialelor si metalurgie, tensiuni si deformatii tranzitorii si remanente ca si proprietatile ZIT-ului si ale materialului depus in straturile cordoanelor de sudura procesul de stabilire a comportarii la flambaj a grinzilor sudate devine mult mai complex iar modelele matematice de abordare mult mai complicate. In acest context, lucrarea incearca sa simplifice pe cat posibil procesul de calcul prin utilizarea unor relatii statistice pentru aproximarea cat mai precisa a tensiunilor si deformatiilor remanente, introduse de procesul de sudare a grinzilor dublu T. Se obtine astfel o metoda de verificare a influentei pe care tehnologia de sudura o are asupra instabilitatii grinzii si la stabilirea cat mai simpla a incarcarilor critice.

Cuvinte cheie: structura de rezistenta, sudura, grinda dublu T, instabilitate, incarcari critice.

Abstract: In Civil Engineering Design, the steel’s structures had a great importance on the light structures realized used to tall buildings, bridges piles and girders. To realize a smallest loading by the own weigh of the structures components there design is made in elastic-plastic state and the global and local instability become more important. The actual trends in the building design consist in using the flexibility of the welding joints technology in almost all the steel’s buildings structures and these work try to give a way for establish an correlation between welding technology and diverse national and international design codes. As the welding technology inquire knowledge in a diverse area of science, heat and fluid flow,material science and metallurgy, stresses and strains generation and distribution between welding processes and the residual stresses and strains distribution, the residual deflections and technological properties in the welded HAZ and added materials the process of analyzing their influence on the girders become more complex and the mathematical models become more complicate. In that context, this paper try to simplify the calculus process by use some statistical low to approximate some of the complexes phenomenon and get good estimations on the residual stresses induced by the welded process in the double T profile. The verification of the influence of technology on the girder instability becomes easy to be estimate and the critical loads too.

Keywords: structure, welding, double T beam, instability, critical loads

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