Sensitivity Analysis on Ultimate Strength of Stiffened Aluminum Plates under Combined Inplane Compression and Lateral Pressure

Aluminum structures for marine applications have normally been built by welding. It is well recognised that welding significantly affects the behaviour of aluminum alloys. In particular, heat affected zone (HAZ) is softened by welding, and this reduces the ultimate strength of welded aluminum structures. It is of vital importance for structural designers to better understand how fabrication by welding affects the aluminum panel ultimate strength characteristics.

It is commonly accepted that the collapse characteristics of welded aluminum structures are similar to those of welded steel structures until and after the ultimate strength is reached, regardless of the differences between them in terms of material properties. However, it is also recognised that the ultimate strength design formulae available for steel panels cannot be directly applied to aluminum panels even though the corresponding material properties are properly accounted for. One of the major reasons for this is due the fact that the softening in HAZ reduces the ultimate strength behaviour of welded aluminum structures, whereas it can normally be neglected in welded steel structures.

There are some research works on the ultimate strength behaviour of aluminum unstiffened/stiffened panels under longitudinal inplane compression. In spite of that, studies on the collapse behaviour of such panels under the combined action of lateral pressure and axial compressive loads are rarely published. Aluminum stiffened panels applied in the construction of high speed crafts are under big magnitudes of lateral hydrostatic and hydrodynamic loads.

It is aimed in this paper to perform numerical collapse simulations on the aluminum stiffened panels under combined lateral pressure and axial inplane compression, applying a series of non-linear finite element analyses on such plate elements. Both material and geometric nonlinearities are taken into account. The values of lateral load, panel geometric properties and HAZ width are changed in a systematic manner. Buckling, post-buckling, ultimate strength and post-ultimate strength characteristics of the panels are investigated in details.