Numerical simulation of deformations in laser welded T-joint is carried out in this study. The analysis is performed using Abaqus FEA engineering software. Additional author’s numerical subroutines, written in FORTRAN programming language are used in computer simulations where models of the distribution of movable laser beam heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Thermomechanical properties of welded material changing with temperature are taken into account in the analysis. Presented results of numerical simulations performed for the laser beam welding of two perpendicularly arranged sheets include temperature distribution, kinetics of phase transformations in solid state, thermal and structural strain as well as estimated welding deformations.
 W.M. Steen, Laser Material Processing; London; Springer (1991).
 A.P. Mackwood, R.C. Cafer, Thermal modelling of laser welding and related processes:aliterature review; Opt Laser Technol 37, 99-115 (2009).
 P. Kujala, A. Klanac, Steel Sandwich Panels in Marine Applications; Brodo Gradnja 56, 305-314 (2005).
 J. Kozak, All steel sandwich panels - new possibilities introduced by laser welding techniques, Przeglad Spawalnictwa 10, 53-59 (2007).
 T. Urbanski, Panele sandwichwwielkogabarytowych konstrukcjach stalowych - charakterystyka problemu łaczenia, Postepy Naukii Techniki 5, 32-44 (2010).
 B. Meteschkow, Sandwich panels in shipbuilding; Polish Maritime Research S1, 5-8 (2006).
 H. Kolsters, P. Wennhage, Optimisation of laser-welded sandwich panels with multiple design constraints, Mar Struct 22, 154-171 (2009).
 J. Jelovica, J. Romanoff, S. Ehlers, P. Varsta, Influence of weld stiffness on buckling strength of laser-welded web-core sandwich plates, J Constr Steel Res. 77, 12-18 (2012).
 D. Deng, H. Murakawa, FEMprediction of buckling distortion induced by welding in thin plate panel structures; Comp Mater Sci. 43, 591-607 (2008).
 J. Romanoff, P. Varsta, H. Reme s, Laser-welded web-core sandwich plates under patch loading, Mar Struct 20, 25-48 (2007).
 W. Piekarska, Numerical analysis of thermomechanical phenomena during laser welding process. The temperature fields, phase transformation and stresses, Wydawnictwo Politechniki Czestochowskiej, Czestochowa (2007).
 P. Lacki, K. Adamus, K. Wojsyk, M. Zawadzki, Z. Nitkiewicz, Modeling of heat source based on parameters of electron beam welding process, Arch Metall Mater. 56 (2), 455-462 (2011).
 D. Deng, W. Liang, H. Murakawa, Determination of welding deformation in fillet-welded joint by means of numerical simulation and comparison with experimental measurements, J Mater Process Tech. 183, 219-225 (2007).
 SIMULIA, Abaqus analysis user’s manual. Version 6.7, Dassault System (2007).
 SIMULIA, Abaqus theory manual. Version 6.7, Dassault System (2007).
 W. Piekarska, M. Kubiak, Theoretical investigations into heat transfer in laser-welded steel sheets, J Therm Anal Calorim 110, 159-166 (2012).
 K. Mundra, T. Deb Roy, Calculation of weld metal composition change in high-power conduction mode carbon dioxide