A survey of some buckling problems.

As = stiff eiier area b = postbuckling coefficient (see Fig. 2) D = shell bending stiffness {=Et*/[l2(l *>)]} E = Young's modulus H = spherical cap rise (see Fig. 10) Is = stiffener moment of inertia Kij KZ = foundation moduli (see Fig. 7) k = parameter in imperfection spectrum (see Fig. 8) L = shell length Z = I/TT (buckle length) lc = critical value of / NC = classical buckling load per unit length n = circumferential wave number in spherical cap buckling P = load PC = classical buckling load PS = static buckling load of imperfect structure PD = dynamic buckling load PC = classical buckling pressure R = shell radius (cylinder, sphere, toroidal-segment boundary); correlation function (see Fig. 7) Rx . = meridional radius of curvature of toroidal segment s = stiff ener eccentricity (see Fig. 6) S = power spectral density of imperfection (see Fig. 7) W = deflection of column W = initial deflection of column Z = curvature parameter { =(L/Rt)(l j/)/} S = buckling displacement amplitude d_ — initial displacement amplitude A = rms initial displacement v = Poisson's ratio