In the Faculty of Ocean Engineering and Ship

ABSTRACT

Ship hull structure elements are usually joined by welding. Welding distortions may cause many problems during manufacturing process. In the literature a wide spectrum of suggestions has been proposed for correct estimation of welding deformation , particularly angular ones , in the fillet welded T-joints. In this work a verification of certain methods selected from the literature is presented basing upon the results of the laboratory measurements. To this end, values determined on the basis of engineering hypotheses have been compared with those obtained from the laboratory tests.

The objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive force, and the most important quantities related to the structural behaviour were captured and analysed. A finite element model, accounting for material and geometrical nonlinearities and initial geometrical imperfections, was developed using the commercial software ANSYS. The residual welding-induced stresses were measured in the middle cross-section for two specimens. The initial imperfection was identified by employing a close-range photogrammetry approach. It was concluded that the numerical analyses, based on the finite element model, predict the ultimate strength of stiffened plates accurately, although some deviations were also observed. The detailed analysis with the indication of possible uncertainty is presented, and several conclusions are derived.

Welding proces is basic