AN ANALYTICAL METHOD FOR THE ULTIMATE COMPRESSIVE STRENGTH AND EFFECTIVE PLATING OF STIFFENED PANELS

The aim of the present study is to develop a simple analytical method for calculating the ultimate strength of a stiffened panel subject to uniaxial compression. The behavior of the stiffened panel is analyzed by using a plate-stiffener combination model as representative of the stiffened panel. Three collapse modes, namely plate induced failure, s tiffener induced failure and local buckling of stiffener web are consi dered. While several other approaches to the same problem exist, an an alytical expression of ultimate strength is of value because it can ex plicitly show the influence of different parameters. The given formula tions can be applied to stiffened plating employing all types of stiff ener profiles. The Perry-Robertson approach is used to derive the crit eria for plate induced and stiffener induced failures without rotation of stiffener web. The effect of possible stiffener web buckling is in cluded through closed form expressions for predicting the elastic buck ling strength of the stiffener web taking account of the influence of rotational restraints at the plate-stiffener and stiffener web-flange intersections. The web buckling strength expressions are used together with the Johnson-Ostenfeld formulation which provides a simple plasti city correction. The influence of initial imperfections (initial defle ction and welding induced residual stresses) for both plating and stif fener are taken into account. As verification, the theoretical solutio ns from the study are compared with some existing experimental results for stiffened panel strength under uniaxial compression. As an intere sting contribution, this study develops, presents, and uses a new refi ned procedure to reasonably accurately evaluate the effective cross se ctional area of the representative plate stiffener combination in the stiffened panel. The effective width of plating between stiffeners is analytically formulated, accounting for applied compressive loads, ini tial deflections, and welding induced residual stresses. (C) 1998 Else vier Science Ltd. All rights reserved.