Buckling of a Long, Axially Compressed, Thin Cylindrical Shell With Random Initial Imperfections

The effect of random geometric imperfections on the maximum load-carrying capacity of an axially compressed thin cylindrical shell is studied. Following a perturbation approach, equations are derived which relate the first and second-order statistics of the maximum load to the statistics of the initial imperfections. Assuming that the imperfections are represented by Gaussian stationary and ergodic random processes, it is shown that the mean maximum load is expressible in quadrature forms involving the power spectral density of the initial imperfection. Furthermore, the maximum load is seen to be equal to its mean value with probability one. A simple asymptotic formula for the maximum load is derived assuming the variance of the initial imperfection is small. In this case the critical load depends only upon the imperfection variance and the power spectral density at a given wave number. For the types of imperfections considered, it is found that random axisymmetric imperfections reduce the load-carrying capacity of the cylindrical shell more than nonaxisymmetric imperfections.