COMPARISON OF THE ANALYTICAL APPROACH WITH THE FINITE ELEMENT METHOD FOR DETERMINING THE NATURAL OSCILLATION FREQUENCIES OF A CYLINDRICAL SHELL

The article presents the results of comparing the natural oscillation frequencies for cylindrical shells placed in a ground environment obtained using the analytical method and the finite element method in the Lira PC. When determining the frequencies in the Lira PC, it was found that in this software package it is not possible to properly take into account the internal pressure in the cylindrical shell, as well as the longitudinal force, therefore the results are given without taking into account these parameters. The comparison of the results showed good convergence, the difference is no more than 10%. Based on the conducted research, it was concluded that the analytical method gives a more accurate result, since it allows taking into account many additional factors compared to the Lira PC, therefore, increases the reliability of the structure and can be recommended for performing calculations when designing large-diameter trunk pipelines.