Numerical study of the plastic behaviour in tension of welds in high strength steels

Abstract

The influence of the mismatch between material properties and constraint on the plastic deformation behaviour of the heat affected zone of welds in high strength steels is investigated in this study, using finite element simulations. An elastoplastic implicit three-dimensional finite element code (EPIM3D) was used in the analysis. The paper presents the mechanical model of the code and the methodology used for the numerical simulation of the tensile test of welded joints. Numerical results of the tensile test of welded samples with different hypothetical widths for the Heat Affected Zone and various material mismatch levels are shown. The analysis concerns the overall strength and ductility of the joint and in relation to the plastic behaviour of the heat affected zone. The influence of the yield stress, tensile strength and constraint on the stress and plastic strain distribution in the soft heat affected zone is also discussed.

Influence of the soft zone on the strength of welded modern HSLA steels

“…Nedavne simulacije konačnim elementima ovog problema sproveli su na pr.Rodrigues i dr. [16] or Mochizuki i dr. [17]. Ova istraživanja opisuju stanje napona i deformacija unutar mekog međusloja i čvrstoću celog uzorka pod poprečnim zatezanjem.…”

Numerical and Experimental Investigation of Tensile Behavior of Laser Beam Welded TRIP700 Steel

“…14,15) In this context, it is important to study the influence of the welding process on the overall mechanical behavior of the joint. However, the experimental analysis of the stress-strain distribution in a welded joint is a very difficult task because of the non-linearities involved in the process, such as the different elastoplastic behavior of the various welded zones, its geometries, the non-homogeneous strain and stress distribution makes all possible experimental analysis very complicated.…”

“…It is possible to analyze individually the various phenomena that occur in a tensile test of a welded joint using numerical simulation. 14) Numerical simulation is an effective tool for the clarification and confirmation of experimental observations. The accuracy of the simulation, however, depends on the availability of accurate mechanical properties for both the base metal and the weld region.…”

“…Many attempts were carried out to numerically simulate the tensile behavior of the welds. 14,16) The evaluation of elastoplastic behavior of laser beam welded TRIP700 steel under uniaxial tensile testing by experimental procedure and numerical simulation was the main goal of this study. This paper aims to evaluate and simulate the mechanical behavior of laser beam welded TRIP700 steel sheet under uniaxial tensile loading.…”

Characterization of mechanical properties by indentation tests and FE analysis – validation by application to a weld zone of DP590 steel

“…In particular, the slow cooling condition after welding processes can induce the heat affected zone (HAZ) to soften for high-strength steels (Thaulow et al, 1994;Wojnowski et al, 2000). In order to predict the overall mechanical behavior of the welded high-strength steel sample, the effects of the assumed amount of softness and the size of the HAZ area were successfully evaluated on crack behavior (Rodrigues et al, 2004a) and tensile performance (Rodrigues et al, 2004b), confirming the necessity of characterized mechanical properties of the HAZ as well as the weld zone for reliable performance predictions in the process design stage. Recently, methods to characterize the weld zone properties of the laser welded or friction stir welded TWB sheets have been developed based on the uni-axial tension test in conjunction with the rule of mixture (Abdullah et al, 2001) or the uni-axial tension test with ASTM sub-sized specimens (Woo et al, 2006).…”