This paper presents the analysis results of investigations on the deformations and velocities during the cold rolling of strips of aluminium alloys AW2024 and AW5083 obtained with an application of the finite-element method (FEM) and the conventional rolling theory. The results of the simulation obtained using the FEM software DEFORM-2D were analysed for the displacements, effective strain and velocity of rolling. The diagrams of the changes in these values along the deformation zone were presented together with the identified characteristics of the trajectories of the surface and axis as the boundary surfaces for simulating the cold rolling of the strips. The finite effective strains were compared with the degree of reduction of the strip thickness, and equations were derived for the dependence of their ratio on the starting thickness of a strip. The equations for the dependence of the velocity of a strip and the roll ratio on the degree of reduction due to the control of forward and backward slips were also derived. The reliability of the obtained results and derived equations was tested with experimental tests, theoretical relationships for plane strain and the results for the forward slip published in the literature. Keywords: cold rolling, FEM, displacements, effective strain, forward slip lanek predstavlja analizo rezultatov preiskav deformacije in hitrosti pri hladnem valjanju trakov aluminijevih zlitin AW2024 in AW5083, dobljenih z uporabo metode kon~nih elementov (FEM) in konvencionalne teorije valjanja. Analizirani so bili rezultati simulacije, dobljene s FEM programsko opremo DEFORM-2D, za raztezek, efektivno obremenitev in hitrost valjanja. Predstavljeni so diagrami sprememb teh vrednosti vzdol`deformacijske cone, skupaj z identifikacijo zna~ilnosti trajektorij povr{ine in osi, kot mejnih povr{in za simulacijo hladnega valjanja trakov. Kon~ne efektivne obremenitve so bile primerjane s stopnjo redukcije debeline trakov in razvite so bile ena~be za odvisnost njihovega razmerja od za~etne debeline traku. Razvite so tudi ena~be za odvisnost hitrosti traku in razmerja valjev na stopnjo redukcije zaradi kontrole prehitevanja in zaostajanja traku. Zanesljivost dobljenih rezultatov in razvitih ena~b je bila preizku{ena s preizkusom, s teoreti~nimi odvisnostmi za ravninsko napetost in za rezultate prehitevanja, objavljenega v literaturi. Klju~ne besede: hladno valjanje, FEM, raztezek, efektivna obremenitev, prednji zdrs

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A joint of lattice aluminium welded structure made of circular hollow sections (CHS) has been analysed. Aluminium alloy EN AW 6082-T6 was used. Calculation of ultimate load bearing capacity of lattice structure web member assumes check of element load bearing capacity for the following calculation situations:- calculation of ultimate load bearing capacity of compressed elements with the influence of buckling,- calculation of ultimate load bearing capacity of compressed elements with the influence of HAZ,- calculation of ultimate load bearing capacity of tensioned elements with the influence of HAZ,- calculation of ultimate element force in truss joint, depending on joint construction.The first three checks are independent of type and characteristics of truss chords. They depend only on elements connection manner and geometrical characteristics of web members. The fourth condition directly depends on relation of chord and web member characteristics, i.e. ratio of their diameters and tube wall thicknesses. The choice of joint geometry, gap between elements in joint as well as joint eccentricity are also important for ultimate force in web member. Check of K-joint ultimate bearing capacity is particularly needed for welded joints due to aluminium strength decrease caused by HAZ (Heat Affected Zone) effect.European standard EN 1999 for aluminium structures design has not defined ultimate load of web members regarding type and characteristics of joint connection.Value of ultimate force in web member of K-joint, depending on connection type, by means of expressions defined in EN 1993-1-8 (Design of steel structures - Part 1-8: Design of joints), has been analysed. Comparative analysis has been done by means of ANSYS modelling, taking into consideration real characteristics of aluminium alloy and ultimate load bearing capacity reduction in the vicinity of weld due to HAZ effect. The main goal of the paper is to analyse capability of expressions from EN 1993-1-8 for steel structures to be used in aluminium structures, having in mind quoted limitations.