The wave propagation and vibrational energy flow characteristics of a plate with a part-through surface crack

In the view of structure-borne sound, vibrational wave and energy flow characteristics of infinite thin plate of finite width with a part-through surface crack are investigated. The case of an all-over part-through crack parallel to the finite side of the plate is considered. The crack is modeled as a line spring and the flexibility of the spring is deduced from the relationship between the strain energy and stress intensity factor in fracture mechanics. The responses of both intact plate and cracked plate under the excitation of harmonic force are reduced with wave propagation approach, then the input energy flow and transmitted energy flow of intact and cracked plates are calculated. The results show that the vibrational energy flow of cracked plate is highly related to the depth and location of the part-through crack. The location and the depth of the crack can be identified by the contour lines of normalized input energy flow with different driving frequencies. The research provides theoretical basis for the crack detection by measuring the vibrational energy flow in cracked plate structures.