Structural assessment of stainless steel stiffened panels

Stiffened plate panels present several applications in Engineering, for instance, in naval/offshore structures, where they are employed as primary elements of ships and vessels. An essential aspect of the failure mechanisms of stiffened plated panels is the initial geometrical imperfections and residual stresses embedded in such structures due to the fabrication processes. Some technical design guides present rules to be applied to the design of carbon steel stiffened plated panels. However, with the technological evolution of the materials and their more strict demands on corrosion and mechanical resistance, it is necessary to utilise special steel whose design is not covered in the codes, as mentioned earlier. This work aims to assess the ultimate resistance of stainless steel stiffened plated panels and verify the influence of different initial imperfections on their capacity. In order to achieve this objective, experimental tests were carried out at the laboratory of stainless steel stiffened panels with an aspect ratio between the panel length and the stiffener spacing of 2.7 and 4.35 to cover the practical values used in the naval/offshore structures. Afterwards, a FE model was developed and calibrated against experimental results. A parametric analysis was performed to enlarge the database to check if the current rules applied to carbon steel structures can be applied to stainless steel stiffened plated panels. The results showed that some design rules could provide conservative and non-conservative designs for low and high slenderness, respectively. Finally, a new equation based on the calibration of the Cx parameter (ratio of the ultimate strength concerning uniaxial stress to the specified minimum yielding point of the plate in the longitudinal direction) was proposed providing improved results.