Effect of three-dimensional welding-induced residual stress and distortion fields on strength and behaviour of flat-bar stiffened panels

Abstract

The influence of welding-induced residual stress and distortion on the behaviour of welded, flat-bar stiffened plates under uniaxial compression is examined, using finite-element simulation techniques. Residual stresses and distortions due to welding are simulated by three-dimensional thermo-elasto-plastic finite-element analysis, and the behaviour of stiffened plates under compressive axial loads is evaluated considering various stiffened plate geometries. Welding-induced residual stress and distortion distributions are examined, and the behaviour of stiffened plates under compressive axial loads with and without welding-induced residual stress is compared with International Association of Classification Societies design formulae. Results of the numerical analyses reveal that welding-induced residual stresses reduce the ultimate strength of flat-bar stiffened plates by as much as 18%. Load shortening curves generated by finite-element analysis are compared with curves derived from design formulae, showing good agreement among ultimate strength values predicted by the two methods. There is, however, some discrepancy between the post-ultimate capacities of stiffened plates predicted by the two methods, which may influence the accuracy of ultimate strength calculations for ship hull girders.