b d E E0 h width of column eccentricity of loading tangent modulus elastic modulus depth of column i = integer L = half length of column M = bending moment N = number of intervals in £ direction NJ = number of intervals in // direction n — constant P = load pc = critical load R = radius of cross section w = transverse deflection of centerline x = coordinate y — coordinate a,-, ft = constants ylt y2 = dimensionless £1 and s2 A = interval in £ direction d = increment e = axial compressive strain £ l>£2 = strains at face of column 9 = interval in r\ or fj direction a = axial compressive stress o! = stress at the intercept of the stress-strain curve and a line through the origin with a slope 0.7£0.