05.03: Weld residual stresses effects in the design of welded plate girders: Simulation and Implementation

Abstract

Eurocode 3 offers different possibilities on a numerically-aided design of welded plate girders. In this, a geometrically and materially nonlinear analysis of the imperfect structure (GMNIA) provides the theoretically highest possible degree of realism. A correct implementation of "imperfections" is of critical importance in the practical application of this method. The current design rules are based on long term experience in terms of traditional ("old") welding procedures and regular ("low strength") steel grades. Thus, they provide very approximate (but safe) rules for these structures. With the introduction of modern shop welding operations and materials, many of these assumptions seem to be over-conservative. A revision of these rules is being processed in different national and international research projects. This particular study focusses on the weld residual stresses and their effects in conventional steel S355 and high strength steel S690. Metal active gas (MAG) welding under shop welding conditions was used. The measurement of weld residual stresses on component-like samples (carried out by the BAM Bundesanstalt für Materialforschung und -prüfung in Berlin) has been widely published. The hereupon based (simplified) welding simulation as part of a subsequent structural analysis is shown here. A novel numerical approach how to directly incorporate the results into large structural components models is presented. The capacity analysis is performed on a simple example for weak-axis buckling. The results indicate significant improvements in the utilization of load-bearing capacity and underline the superior buckling assignment for the S690 compared to conventional S355. The experimental validation of the findings is currently being prepared.

Marchant - Rankine’s - Murzewski approach for modelling of the buckling resistance of welded I-section columns

“…Based on the above, it is important to emphasize that material and geometrical imperfections have to be considered individually in order to define the separate effect of material and geometric imperfections on the column buckling strength. The aspects of FEM modelling and the problem of postwelding residual stress influence on the stability of steel members were also presented in [9][10][11][12]. An alternative method of assessing the load capacity of steel elements to this presented in the paper is the concept of equivalent geometric imperfections, which is in compliance with the so-called Eurocode's general method.…”

Ultrasonic and FEM residual stress measurement in dissimilar St37–St52 welding

“…Huang et al 22 S355JR 2 316L dissimilar metal welding SYSWELD Heinze et al 23 S355J2 + N (ASTM A572 Gr.50) SYSWELD Chukkan et al 24 Stainless steel welding SYSWELD Yang 25 Stainless steel welding SYSWELD Gkatzogiannis al. 26 Two multi-phase ferritic steel grades -Launert and Pasternak 27 Conventional steel S355 and high strength steel S690 -Danielewski et al 28 Dissimilar low carbon and austenitic steel joint Simulact Welding software Zhao et al 29 T92/S30432 dissimilar welded pipe -Liu et al 30 Dissimilar welding of 316L and low alloy steel SYSWELD Xie et al 31 DP780 steel thin-plate welded joints using Gas Tungsten Arc (GTA) welding and Ultrasonic-wave-assisted Gas Tungsten Pulsed Arc (U-GTPA) welding…”

The simplified method of the equivalent compression flange

“…Strain measurements in the area of the welds could only be taken at one side of the flanges. The residual stresses inside the flange, in the area of the welds, were calculated by considering equilibrium conditions of the cross-section and plastic strains according to [12]. The distributions of the residual stresses at the remaining cross-section were supplemented by symmetry and equi-ment taking advantage of the symmetry.…”