Numerical Study On Load-carrying Capacity Of Aluminum Alloy Pontoon Hull

There is exigent need of renovations on pontoon, and aluminium alloy will inevitably be applied to the hull. The failure mechanisms and the load-carrying capacity of the aluminium alloy pontoon hull structure are investigated numerically, with both material and geometry nonlinear effect considered. Then the load-carrying capacity of foam-filled aluminium alloy pontoon hull is studied. The main contents and innovative works in this paper are as follows:(1) Based on published experimental data, ANSYS is applied to study the load-carrying capacity of sandwiched aluminium deck with trigonal stuffing. And the influence of boundary conditions is intensively discussed. It is concluded that boundary has great influence on load-carrying capacity of the deck, and both the faceplate and the bottom plate should be jointed to the web.(2) Aluminium alloy pontoon hull is designed and its FEM model is established, which is analyzed with material and geometry nonlinear effect as well as hydrostatic pressure taken into account. The buckling modes and stress distributing of the hull under wheel load is studied, and its load-carrying capacity and failure mechanisms are obtained. The results show that aluminum alloy pontoon hull has considerable post-buckling carrying capacity and the ultimate load mainly depends on the strength of the materials. The hydrostatic pressure has little influence on the load-carrying capacity.(3) The influence on load-carrying capacity of the thickness of webs and diaphragms is studied and the reasonable thickness is obtained. Then load-carrying capacity of the hull is investigated as load applied at diffenent locations. The results show that the load-carrying capacity may also depend on the buckling of plates if the load is applied near the webs or diaphragms. The webs have relatively little influence and their reasonable thickness is supposed to be 7～8mm, and the diaphragms have biggish influence , whose thickness is supposed to be 9mm at least. The designed hull can support wheel load of LT-120.(4) FEM model of foam-filled aluminium alloy pontoon hull is established, in which the foam is modeled by nonlinear spring elements. Its load-carrying capacity and failure mechanisms are studied. And the influence of the foam'density is analyzed. It shows that the filled foam is propitious to load carrying, and the ultimate load increase with the foam'density, but the increment is little. In practice, low-density foam should be used.