Reconstructing slow-time dynamics from fast-time measurements

摘要

This paper considers a dynamical system subjected to damage evolution in variablenoperating conditions to illustrate the reconstruction of slow-time (damage) dynamicsnusing fast-time (vibration) measurements. Working in the reconstructed fast-time phasenspace, phase space warping-based feature vectors are constructed for slow-time damagenidentification. A subspace of the feature space corresponding to the changes in thenoperating conditions is identified by applying smooth orthogonal decomposition (SOD) tonthe initial set of feature vectors. Damage trajectory is then reconstructed by applying SODnto the feature subspace not related to the changes in the operating conditions. The theorynis validated experimentally using a vibrating beam, with a variable nonlinear potentialnfield, subjected to fatigue damage. It is shown that the changes in the operating conditionn(or the potential field) can be successfully separated from the changes caused by damagen(or fatigue) accumulation and SOD can identify the slow-time damage trajectory.