COLLAPSE OF AXIALLY COMPRESSED CYLINDRICAL-SHELLS WITH RANDOM IMPERFECTIONS

The establishment of an International Imperfection Data Bank is discussed. Characteristic initial imperfection distributions associated with different fabrication techniques are shown. Using the first-order, second-moment analysis, a stochastic method is presented, whereby the stability of isotropic, orthotropic, and anisotropic nominally circular cylindrical shells under axial compression, external pressure, and/or torsion possessing general nonsymmetric random initial imperfections can be evaluated. Results of measurements of initial imperfections are represented in Fourier series and the Fourier coefficients are used to construct the second-order statistical properties needed. The computation of the buckling loads is done with standard computer codes and includes a rigorous satisfaction of the specified boundary conditions. It is shown that the proposed stochastic approach provides a means to combine the latest theoretical findings with the practical experiences spanning about 75 years in an optimal manner via the advanced computational facilities currently available.