Aluminium alloy is characterized by the high strain-hardening rate relative to Young's modulus and round stress-strain relationship above elastic limit. The reduction of strength (softening) in heat affected zone of welded aluminium structures is also one typical characteristic of aluminium alloy. In addition, the shaped stiffened plates with a taper crosssection in plate are widely used in aluminium ship structures. In this paper, the influences of the strain-hardening rate, stress-strain relationship, welding residual stress, reduced strength in heat affected zone and taper cross-section on the buckling/plastic collapse behaviour of aluminium stiffened plates are investigated by using FEM analyses. The simplified method to estimate the ultimate strength of aluminium stiffened plates is developed considering the observed behaviours.
Recently, high-speed ships applying aluminium alloy have been constructed. In general, stiffened plates are widely used for the main structural members of the aluminium ships like in steel ships. It is therefore important to examine the buckling/plastic collapse behaviour and ultimate strength of aluminium stiffened plates under thrust. Aluminium alloy is characterized by the high strain-hardening rate relative to Young's modulus and round stress-strain relationship above elastic limit. The reduction of strength (softening) in heat affected zone is also one typical characteristic of aluminium alloy. Although some research works (e.g., Tanaka et al., 1996, Zha et al., 2000) on aluminium stiffened plates have been performed considering these characteristics, the investigation into its bucklingplastic behaviour is not yet sufficient compared to steel stiffened plates. However, little study has been performed on the influence of the cross-section on the bucklingplastic collapse behaviour. In this paper, the influences of the strain-hardening rate, stress-strain relationship, welding residual stress, reduced strength in heat affected zone and taper cross-section on the bucklingplastic collapse behaviour of aluminium stiffened plates are investigated by using FEM analyses.
