Compartment level progressive collapse analysis of lightweight ship structures

Abstract

The continued development of large high speed ships, often constructed from aluminium alloy, has raised important issues regarding the response of lightweight hull girders under primary hull girder bending. In particular, the response of lightly framed panels in compression may be influenced by overall panel buckling over several frame spaces. Therefore, to provide improved ultimate strength prediction for lightweight vessels, an extended progressive collapse methodology is proposed. The method has capabilities to predict the strength of a lightweight aluminium midship section including compartment level buckling modes. Nonlinear finite element analysis is used to validate the extended progressive collapse methodology.

Overall buckling of lightweight stiffened panels using an adapted orthotropic plate method

“…These are taken from plate [14] and stiffener [15] datasets. An example dataset for unstiffened plates are shown in Figure 4.…”

“…Full details of the finite element analysis methodology and model setup are found in Benson [15] and only a brief summary is given here. The panels were developed with a range of plate and column slenderness.…”

“…However recent studies have shown, through analytical formulations and nonlinear finite element analysis, that overall buckling may be a possible failure mode in certain ship panels [3]. Overall buckling modes can develop for panels which are either lightly framed or have a large span between strong supports.…”

“…An extension to the progressive collapse method is therefore proposed in Benson et al [3] which can be used to predict the ultimate strength of a ship's hull girder accounting for buckling over several frame spaces. Fundamental to this procedure is the prediction of the behaviour of the elements within the structure.…”

“…The simplified progressive collapse method presented by Dow [4] has been extended by Benson et al [3] to account for both interframe and overall collapse modes. A key innovation in the extended method concerns the way a girder is subdivided into stiffened panel elements, and then the way the stiffened panel elements are treated within the progressive collapse calculations.…”