Role of Experiments in Improving the Computational Models for Composite Shells

摘要

It appears from the experimental results published to date that in many cases the stability of thin-walled layered or fibre wound composite shells is mainly dependent on the boundary conditions imposed and the initial geometric imperfections present in the specimens. Using the first-order, second-moment analysis, a stochastic method is presented whereby the stability of 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 the computer codes ANISOT and STAGS and include a rigorous satisfaction of the experimental 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 25 years in an optimal manner via the advanced computational facilities currently available.