Statistical description and numerical calculations of cylindrical vertical tanks with initial geometric imperfections

In the paper a numerical calculation of a steel cylindrical vertical tank with initial geometric imperfections in its side surface is presented. The real, measured in situ imperfections have been applied as the test data. The influence of these discrepancies on the stress field are analysed and considered as an important factor. The random nature of the imperfections is studied with the help of statistical analysis. On the basis of the proposed identification procedure a nonhomogeneous correlation function is defined. The function allows to generate random fields of imperfections consistent with the measured ones. In the generation use is made of an effective version of the rejection method and of the conditional probability distribution formula. The identification and generation methods can be directly applied to the petrol tank reliability estimation.