Contents lists available at ScienceDirect Ocean Engineering journal homepage: www.elsevier.com/locate/oceaneng An engineering approach for a T-joint fillet welding simulation using simplified material properties Mato Perić b , Zdenko Tonković a, ⁎ , Ivica Garašić a , Tomaž Vuherer c a University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, I. Lučića 5, 10000 Zagreb, Croatia b Bestprojekt, Bureau of Energetics and Mechanical Engineering Ltd., Petrovaradinska 7, 10000 Zagreb, Croatia c University of Maribor, Faculty of Mechanical Engineering, Smetanova ulica 17, 2000 Maribor, Slovenia ARTICLE INFO Keywords: T-joint fillet weld Finite element analysis Thermo-mechanical material properties Residual stress Plate deflections Stress intensity factor ABSTRACT In the present study, a three-dimensional numerical simulation of a T-joint fillet welding of two plates is performed using simplified material properties. To investigate the influence of the temperature-dependent thermo-mechanical material properties of carbon steel on the transient temperature distributions and weld- induced residual stresses and deformations, two different cases are considered. In the first case, all the material properties, except the yield stress, are taken as constant at room temperature. In the second case, to calculate the temperature-dependent material properties, the polynomials defined by the ASCE manual are used. From the simulation results, it is concluded that, compared with the reference case that uses the true properties of the chosen material S355JR, the first case of simplification is more suitable for the prediction of plate deflections, while the second case is more favorable for the assessment of thermal fields, heat-affected zones, residual stress fields and stress intensity factors. 1. Introduction Due to their low prices, carbon steels are the most frequently used steels in mechanical engineering, shipbuilding, petrochemical industry, civil engineering, and other fields, and they comprise approximately 90% of total world steel production (Fish, 2007). The welding of these steels is usually carried out by fusion procedures that generate a large amount of heat, which leads to local melting of the material through the addition of a molten metal electrode. An inevitable and harmful consequence of this process is that due to the rapid cooling in the material, residual stresses and permanent deformations occur with microstructural changes in the welded joint. In the presence of cracks in the material, tensile residual stresses in combination with workload accelerate their growth and lead to shorter life of structures (Oh et al., 2015; Ren et al., 2010; Predan et al., 2010; Schnubel and Huber, 2012). The deformation of the structure due to the welding leads to changes in its dimensions, which causes problems during the assembly. The elimination of the consequences of fusion welding is quite complex and requires additional financial costs. To minimize these conse- quences, it is necessary to know the state of the residual stresses and strains in the structure in the design phase. Currently, due to the rapid progress of computer technology, numerical simulations are used to avoid expensive experimental measurements (Zhang et al., 2015; Li et al., 2015; Chen et al., 2015; Jiang et al., 2014; Tchoumi et al., 2016; Shen and Chen, 2014). The accuracy of the numerical simulation directly depends on the thermal and mechanical properties of the material, from room temperature up to the melting point. Because the data on temperature-dependent material properties are often difficult to access or completely inaccessible, there are necessary alternatives. In the example of a butt-welded aluminum plate, Zhu and Chao (2002) concluded that with sufficient precision, all thermal and mechanical properties can be taken at room temperature, except for the yield strength of the materials that must be treated as temperature depen- dent. Heinze et al. (2012) investigated the residual stress distribution in butt-welded steel plates and concluded that their deformation strongly depended on the thermal conductivity, heat flux model and shape of the weld. Armentani et al. (2007) also studied the magnitude of the welding residual stresses in butt-welded plates and found that in the weld vicinity zone, the weld residual stresses significantly depend on the coefficient of thermal conductivity. Numerical investigations were carried out by Bhatti et al. (2015) to study the influence of the thermomechanical properties on the welding residual stress and distortion in T-fillet joints, and they concluded that all the properties of the material except for the yield stress can be taken at room temperature, but only for the stress field calculations. For the calcula- tion of the plate deflections, it is still necessary to know the dependence http://dx.doi.org/10.1016/j.oceaneng.2016.10.006 Received 11 December 2015; Received in revised form 12 August 2016; Accepted 3 October 2016 ⁎ Correspondence to: Institute of Applied Mechanics, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb, Croatia. E-mail addresses: mato.peric@fsb.hr (M. Perić), zdenko.tonkovic@fsb.hr (Z. Tonković), ivica.garasic@fsb.hr (I. Garašić), tomaz.vuherer@um.si (T. Vuherer). Ocean Engineering 128 (2016) 13–21 0029-8018/ © 2016 Elsevier Ltd. All rights reserved. crossmark