Experimental demonstration of local attractor variance as a damage indication feature

In vibration-based structural damage assessment, the proper selection and extraction of appropriate features remains an important component of the overall process. These features ideally must be both sensitive to a particular damage scenario and insensitive to ambient influences within some statistical confidence. A novel approach has been introduced in previous works which described the local attractor variance ratio as a state-space-based feature (in combination with appropriate chaotic excitation input), which was shown in numerical experiments to be superior to modal-based features in both detecting and quantifying damage under several scenarios. In this work, we apply this new technique to a simple five-degree-of-freedom experimental system, where "damage" is induced through a spring stiffness change. In addition, we present a variation of this feature, both of which seek to quantify states space distortion with damage.