The Paton Welding Journal, 2022, №09



2022 №09 (05)

DOI of Article 10.37434/tpwj2022.09.06

2022 №09 (07)

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The Paton Welding Journal, 2022, #9, 33-40 pages

Mathematical model of determination of residual stresses and strains in friction stir welding of aluminium alloy

B.R. Tsaryk, O.F. Muzhichenko, O.V. Makhnenko

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

Abstract
A rater simple and efficient mathematical model of the process of friction stir welding (FSW) was developed, which is focused on fast determination of residual welding stresses and strains with engineering precision. The model is based on application of the method of thermoelastoplastic deformation of the material, which is used at modeling of arc welding, but instead of the model of arc heat source a model of heat evolution from the working tool friction against the material of the joint element was developed. The model also takes into account the conditions specific to FSW of rigid restraint of the joint elements during welding. The developed FSW model was used to conduct calculations of a butt joint of plates from AMg6 aluminium alloy and to present the results of the characteristic distribution of residual stresses and plastic strains, compared to arc welding of the butt joint. Calculation results derived using the developed model confirm the conclusions of other researchers that at FSW of aluminium alloys undesirable residual stresses and strains also form, but they are lower than with the traditional arc welding methods. Developed model can be effectively used for on-line calculation definition of residual stresses and plastic deformations in the zone of welded joints produced by FSW, with the purpose of further assessment of welded joint strength or prediction of general deformations of large-sized structures. Ways of further improvement of the developed model were outlined with the purpose of further increase of prediction accuracy, also by allowing for degradation of mechanical properties (softening) the aluminium alloy during heating.14 Ref., 1 Tabl., 7 Fig.
Keywords: friction stir welding, aluminium alloy, residual stresses, plastic deformation, mathematical modeling

Received: 09.06.2022
Accepted: 11.11.2022

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