STUDY OF THE INFLUENCE OF THE LOCATION OF COMPOSITE OVERLAYS ON THE VIBRATION FREQUENCIES OF A MAIN GAS PIPELINE

In this paper, a numerical study of a typical section of an overhead main gas pipeline with reinforced composite linings mounted on supports for the analysis of vibration frequencies is carried out. The study was conducted using the finite element method in the ANSYS Workbench software package. The study considers cases with internal working and critical pressure as a load. The result of the study showed that in the variation of the installation of composite linings under the condition of critical pressure, the first eleven oscillation frequencies showed a lower value, and starting from the twelfth frequency, lower values were shown in the operating pressure condition. At the same time, under operating pressure conditions, the location of the composite lining in the variation between supports 2 and 3, as well as in the variation between supports 3 and 4, showed the same results, that is, the change occurred only in 1,4 and 5 forms. In the variation, when the pad is installed between the supports 1 and 2, the shapes 1,3 and 5 were changed. Under conditions of critical pressure, the location of the composite lining in the variation between supports 2 and 3, as well as in the variation between supports 1 and 5, showed the same results, that is, the change occurred in 1,2 and 5 forms. In the variation, when the pad is installed between the supports 3 and 4, the shapes 1,3 and 5 were changed. When comparing all three cases according to the values of the oscillation frequencies, it was established that the value of the oscillation frequencies when installing composite linings in the middle in most cases exceed, that is, of the twenty frequencies listed, 60-70% of the chatot index is higher relative to the other two cases. Thus, the obtained research results can be used to select the location of a carbon fiber lining for banding gas pipelines in a region with seismic activity.