RIGID-PLASTIC MODELING OF BLAST-LOADED STIFFENED PLATES .1. ONE-WAY STIFFENED PLATES

A new rigid-plastic analysis of stiffened plates subjected to uniforml y distributed blast loads is developed. In this first part of a two-pa rt paper, a uniform one-way stiffened plate with clamped ends is model led as a singly symmetric beam, comprised of one stiffener and its tri butary plating. Rigid-plastic analysis is then applied to this beam us ing an idealized piecewise linear bending moment-axial force capacity interaction relation or yield curve. Two solutions to the response are developed. The first solution is in closed form and is based on the s olution of the resulting linearized differential equations. The second solution is obtained by approximating the response as a sequence of i nstantaneous mode responses, where the mode shapes are determined by a n extremum principle which maximizes the rate of change of the kinetic energy. This latter solution may be extended to cases involving non-r igid boundaries and two-way stiffening and this is done in the second part of this paper. Here, the two solution methods are applied to seve ral examples of one-way stiffened plates subjected to various blast-ty pe pulses. Good agreement is obtained between the present results and those from elastic-plastic beam finite element and finite strip soluti ons.