No abstract

No abstract

No abstract

In this paper, the buckling analysis on simply supported rectangular plates and stiffened panels is carried out. Three different plate thicknesses were proposed (i.e., 3 mm, 4 mm, and 5 mm). The thickness of the longitudinal stringers and sub-stiffeners were also varied. The material that was used was marine grade steel. The load versus the displacement curve and the total energy were measured. The buckling analysis results were examined via finite element (FE) computation. To ensure that the results of the methodology for the finite element were reliable, the benchmark buckling analysis of the experimental test was reconstructed. For the selection of mesh size, the element to thickness ratio method (ELT) was used. The results revealed that the thickness of the plate increases the strength of the stiffened panel. The plate thickness of 5 mm increased by 65.7% and 20.61% compared with the 3 mm and 4 mm plate thicknesses. A change in the thickness of the sub-stiffeners does not significantly change the strength of the stiffened panels. Material S355JR-EN10210 produced a higher ultimate panel collapse load compared with S235JR-EN10025 (A) and S235JR-EN10025 (B).

No abstract

No abstract

This paper focusses on steel-welded hemispherical shells subjected to external hydrostatic pressure. The experimental and numerical investigations were performed to study their failure behaviour. The model was fabricated from mild steel and made through press forming and welding. We therefore considered the effect of initial shape imperfection, variation of thickness and residual stress obtained from the actual structures. Four hemisphere models designed with R/t from 50 to 130 were tested until failure. Prior to the test, the actual geometric imperfection and shell thickness were carefully measured. The comparisons of available design codes (PD 5500, ABS, DNV-GL) in calculating the collapse pressure were also highlighted against the available published test data on steel-welded hemispheres. Furthermore, the nonlinear FE simulations were also conducted to substantiate the ultimate load capacity and plastic deformation of the models that were tested. Parametric dependence of the level of sphericity, varying thickness and residual welding stresses were also numerically considered in the benchmark studies. The structure behaviour from the experiments was used to verify the numerical analysis. In this work, both collapse pressure and failure mode in the numerical model were consistent with the experimental model.

The purpose of this paper is to study the effect of selected parameters in ship collision and extend it to assessment of structural crashworthiness on the double-side structure (DSS). A brief concept and implementation of the ship-ship interaction is presented in early discussion, which is followed by fundamental factors in numerical calculation. Initial analysis is addressed to quantify influence of several element formulations types on damage extent and simulation time. According to comparison with certain RoRo collision incident data, the fully integrated version of the Belytschko-Tsay emerges as the most similar in terms of the damage criterion of analysis. Even though ordinary type of the Belytschko-Tsay produces faster time processing, fully integrated version is still chosen as it can prevent undesired phenomena during nonlinear finite element analysis. The next analysis aims to conduct crashworthiness assessment on several regions of the target ship. Collision location and attacking velocity are determined as representative of the external dynamic parameters, while material grade is considered as the internal parameter. Assessment results of the DSS are presented in forms of the statistical calculation to obtain variance percentage, and failure sequence to understand crushing process during side collision. Result tendency indicates that the velocity is nominated as the most influencing parameters to the crashworthiness criteria of the target ship. Keywords Ship-ship collision scenario Á Nonlinear FE analysis Á Shell element formulation Á Double-side structure (DSS) Á Bow-hull interaction Á Material characterization Á Crashworthiness criteria