Vibration Analysis Of Cylindrical Shell With A Circumferential Crack

A cylindrical shell is an important component in the engineering structure.The long-term use may cause crack damage,which in turn causes changes in local stiffness and other characteristics,making the static and dynamic characteristics of cylindrical shell change.By studying the vibration characteristics of a cylindrical shell with cracks,it can provide theoretical guidance for the damage identification of cylindrical shells.In this paper,the free vibration characteristics of cylindrical shells with circumferential surface crack are studied firstly.Based on Flügge shell theory and Helmholtz wave equation,the characteristic equations are established.The line-spring model is used to simulate a circumferential surface crack.The wave propagation method is used to describe the displacement of the cylindrical shell.The solution methods of the natural vibration characteristics of a cylindrical shell with a circumferential surface crack in vacuum and coupled with fluid are proposed respectively.The effects of parameters such as crack depth,crack position,fluid interaction,and boundary conditions on the natural frequency and vibration modes of the cylindrical shell are investigated.Then the modal power flow of the cylindrical shell with circumferential surface cracks is analyzed.The modal power flow index of the cylindrical shell is proposed based on the concept of structural intensity and vibration power flow.The modal power flow distributions of different orders of natural vibration are analyzed.The influence of parameters such as crack depth,crack position and boundary conditions on the modal power flow index of the cylindrical shell is studied.The results show that cracks have a significant effect on the modal power flow distribution of the cylindrical shell.The research content provides theoretical support for damage identification of cylindrical shell based on modal power flow.Finally,the forced vibration characteristics of circular cylindrical shells with circumferential surface cracks are investigated.The solution method of the forced vibration of the cylindrical shell with circumferential surface cracks is proposed.The input power flow is used as an index to study the effects of parameters such as crack depth and crack position on the forced vibration of the cylindrical shell.It provides theoretical guidance for damage identification of cracked cylindrical shells based on vibrational power flow.