D. AFSHARI et al.: PREDICTION OF THE NUGGET SIZE IN RESISTANCE SPOT WELDING ... PREDICTION OF THE NUGGET SIZE IN RESISTANCE SPOT WELDING WITH A COMBINATION OF A FINITE-ELEMENT ANALYSIS AND AN ARTIFICIAL NEURAL NETWORK NAPOVEDOVANJE PODRO^JA PRETALITVE PRI

Abstract

The goal of this investigation is to predict the nugget size for a resistance spot weld of thick aluminum 6061-T6 sheets 2 mm. The quality and strength of spot welds determine the integrity of the structure, which depends thoroughly on the nugget size. In this study, the finite-element method and artificial neural network were used to predict the nugget size. Different spot welding parameters such as the welding current and the welding time were selected to be used for a coupled, thermal-electrical-structural finite-element model. In order to validate the numerical results a series of experiments were carried out and the nugget sizes were measured. The results obtained with the finite-element analysis were used to build up a back-propagation, artificialneural-network model for the nugget-size prediction. The results revealed that a combination of these two developed models can accurately and rapidly predict the nugget size for a resistance spot weld. Keywords: resistance spot weld, nugget size, finite-element analysis, artificial neural network, aluminum alloys Cilj te preiskave je napovedati velikost podro~ja pretalitve pri uporovno zvarjeni aluminijasti plo~evini 6061-T6, debeli 2 mm. Kvaliteta in trdnost to~kastega zvara dolo~ata celovitost konstrukcije, kar je odvisno predvsem od velikosti podro~ja pretalitve. V tej {tudiji sta bili za napovedovanje velikosti podro~ja pretalitve uporabljeni metoda kon~nih elementov in umetna nevronska mre`a. Izbrani so bili razli~ni parametri varjenja, kot sta varilni tok in~as varjenja, za skupni termi~no-elektri~no-strukturni model kon~nih elementov. Za oceno numeri~nih rezultatov je bilo izvr{enih ve~preizkusov in izmerjena je bila velikost podro~ja pretalitve. Rezultati, dobljeni iz analize kon~nih elementov, so bili uporabljeni za gradnjo modela umetne nevronske mre`e za napovedovanje velikosti podro~ja pretalitve. Rezultati so odkrili, da kombinacija teh dveh razvitih modelov lahko zanesljivo in hitro napove velikost podro~ja pretalitve pri uporovnem to~kastem zvaru. Klju~ne besede: uporovni to~kasti zvar, velikost podro~ja pretalitve, analiza kon~nih elementov, umetna nevronska mre`a, zlitine aluminij