A Novel Detection and Localization Approach for Nonlinear Faults in Two-Dimensional Structures

In this study, a novel detection and localization approach for nonlinear faults (loosening bolts or fatigue cracks) in two-dimensional structures is proposed and verified. In this new approach, a two-dimensional discrete multi-degree-of-freedom (MDOF) model, which simulates nonlinear faults as nonlinear damper-spring elements between each mass, is applied to characterize the dynamic behavior of two dimensional structures. With the nonlinear output spectrum and multi-position excitation method, damage features correspond to properties of substructures are derived, and local damage indexes are defined for nonlinear fault detection and localization in substructures. Numerical results of case study demonstrate that the proposed approach is realizable and sensitive to faults in the substructure under diagnosis even though there are faults in other substructures.