A multi-scale pseudo-force model for characterization of damage in beam components with unknown material and structural parameters

Most existing damage characterization exercises require explicitly defined material properties, geometric parameters and boundary conditions of the object to be evaluated. However, satisfying such a rudimental prerequisite can be a challenging task in reality. It may be somewhat difficult or even impossible to exactly acquire these parameters beforehand in some occasions, especially when the object comprises various structural components of distinct material/geometric properties and different boundary conditions. A damage characterization strategy, residing on a multi-scale pseudo-force damage model, was developed with an aim of achieving robust damage evaluation by tolerating ignorance of the knowledge on partial material/structural properties and boundary conditions of the object a priori. Proof-of-concept validation was carried out numerically and experimentally by characterizing a fine crack in an Euler–Bernoulli beam, a structural component included in a system with irregular boundaries, without knowing its material and structural parameters beforehand. Exact characterization results demonstrated the effectiveness and accuracy of the proposed approach. •Damage characterization with unknown material/structural parameters.•A multi-scale pseudo-force damage model for damage modeling and identification.•Improved sensitivity to small damage owing to use of high-order spatial derivatives.•Independence of baseline, global model, rigorous excitation and boundary complex.•Enhanced robustness of damage modeling and detection under noisy conditions.