Abstract: The presence of a crack in a structure affects its dynamic behaviour
under working conditions. Cracks introduce nonlinearities into the system; the
use of such nonlinearities for damage detection should be investigated. A model
of a one-dimensional cracked cantilever bar subjected to longitudinal harmonic
excitation is used to analyse a vibro-impact response as a way to monitor
structural health. The effect of contact nonlinearity due to crack's faces
interaction is considered. This nonlinear information is obtained based on a
combination of the analytical technique and the Matlab-Simulink computation.
The procedure uses a numerical approximation for dynamic compliance operators
and a nonlinear model of contact faces interaction implemented numerically as a
nonlinear feedback. Nonlinear resonant phenomena due to vibro-impact
interaction in the cracked bar are obtained and analysed. A distribution of the
higher harmonics along the bar length, generated due to the nonlinear response
of the crack, is revealed as a function of the distance from the crack.
Recommendations on structural health monitoring of cracked bars due to contact
nonlinearity are presented
