Experimental cable identification via dynamic testing

A linear modal representation of a physical suspended cable, is identified via dynamic testing. As it is well known, cable identification is a challenging task due to the inherent nonlinear behavior of the system and to the likely occurrence of internal resonance conditions. Particularly, the choice of the best identification technique and the minimum number of sensors are not straightforward. A physical cable is arranged in the laboratory environment and it is monitored by means of a triaxial accelerometer and two laser displacement sensors. Two different output only techniques are adopted and compared, for identification purposes. In the former case, impulsive forces of unknown intensity are applied to the cable in different positions. In the latter case, white noise accelerations, exerted by an electromagnetic linear motor, are adopted as the external inputs. The main topics under investigation are: the best positioning of the monitoring sensors and the robustness of the identified parameters with respect to actuator positions and amplitudes of excitation.