Vibrational power flow analysis of thin cylindrical shell with a circumferential surface crack

In the view of structure-borne sound, the structural wave and power flow characteristics of infinite thin cylindrical in vacuo shell with a circumferential surface crack are investigated. In this paper, the equivalent distributed line spring is designed to model the surface crack in the shell. The local compliance matrix due to the presence of the crack is deduced from fracture mechanics and three modes of the crack stress intensity factors and their coupling are considered in the local compliance matrix. The vibration of the thin shell is described by the Flügge shell equations. Under the excitation of radial harmonic line force, the input power flow and transmitted power flow of uncracked and cracked shells are obtained. The results show that the vibrational power flow of cracked shell changes substantially due to the presence of crack, and the change is strongly related to the depth and location of crack. Contours of input power flow at different frequencies are constructed to identify the location and depth of the crack. It is revealed that the power flow in the cylindrical shell structures can be used as an alternative defect information carrier. This research provides theoretical basis for the crack detection by measuring the vibrational power flow in cracked shell structures.