2. Identification of Multiple Cracks Using Perturbation to Dynamic Equilibrium
3. Numerical Verification
3.1. Numerical Model
3.2. Numerical Results
4. Experimental Validation
4.1. Experimental Specimen and Setup
4.2. Experimental Results
5. Concluding Remarks
- The TPF exists at the crack locations only and vanishes at intact locations, based on which the DI is established using the absolute value of the amplitude of the TPF. The occurrence of multiple cracks can be manifested by the singularity peaks in the DI. Furthermore, cracks can be pinpointed by the locations of the peaks.
- To enhance the robustness of the DI against noise interference, multi-scale analysis is integrated into the DI. By sliding a scaled Gaussian window function along a mode shape signal, the “region-by-region” manner is utilized to average noise components in the noisy mode shape. On the other hand, crack-induced singularity peaks in the MDIs are naturally retained for the identification of cracks.
- To deal with unknown material and structural parameters that are required to formulate TPFs in composite laminated beams, a statistic manner is utilized to estimate the constants of the TPFs related to the material and structural parameters. In this regard, the proposed approach is a baseline-free approach, feasible to real scenarios in the absence of material and structural information.
- To remove the node effect that hinders the identification of multiple cracks in beams, an integrating scheme is utilized to fuse identification results associated with multiple mode shapes, whereby even cracks in the vicinity of nodes of mode shapes can be evidently identified.
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
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