THE MODELING OF THE OPENING AND CLOSURE OF A CRACK

The paper presents a method which utilizes substructure normal modes t o predict the vibration properties of a cantilever beam with a breathi ng transverse crack. The two segments of the cantilever beam, separate d by the crack are related to one another by time varying connection m atrices representing the interaction forces. The connection matrices a re expanded in a Fourier series leading to a classical eigenvalue prob lem. Subsequently, the initial formulation is extended to avoid interf erence of the crack interfaces with a time domain formulation. The Lag range multipliers, used to enforce the exact continuity constraints wh en the crack is closed, produce the interfaces forces needed for the m odelling of interface dry friction.