Strength assessment of stiffened FRP panels of small WIG craft

WIG(Wing-In-Ground effect) craft flies close to the water surface by utilizing a cushion of relatively high pressurized air between its wing and the water surface. This implies that such a craft needs to have lightweight structures with adequate strength to resist external hydrodynamic loads. As a part of ongoing efforts at designing, this paper performs the strength assessment of the stiffened FRP panels of small WIG craft. WIG craft considered in this paper has a design landing weight of 1.5-ton and carbon/epoxy composite materials are used extensively to satisfy the design weight of the structural members. The strength assessment of the stiffened FRP panels is done in accordance with the procedures developed within the first-ply-failure regime in conjunction with the selection of a laminated composite plate theory and failure criteria for anisotropic materials. Structural configurations of the panel are varied under the constraint of equal panel weight. They are laminated composite plates having different ply stacking sequences and sandwich plates having different core materials. As a result, the loads and deflections that produce failures, in terms of the first-ply-failure, are calculated and useful findings are derived for the structural design of WIG craft.