COUNTERINTUITIVE QUASI-PERIODIC MOTION IN THE AUTONOMOUS VIBRATION OFCRACKED TIMOSHENKO BEAMS

The time domain behaviour of a cracked Timoshenko beam is constructed by alternation of two linear models corresponding to the open and clos ed condition of the crack. It might be expected that a response which is composed of the alternation of two systems with different propertie s would extinguish the periodicities of the constituent sub-models. Th e numerical studies presented illustrate the perpetuation of these fea tures without showing any evidence for the creation of periodicities b ased on a common assumption of the mean period of a bilinear model. (C ) 1995 Academic Press Limited