Issue 48

J. Prawin et alii, Frattura ed Integrità Strutturale, 48 (2019) 513-522; DOI: 10.3221/IGF-ESIS.48.49 520 experimental specimen, employed in the present work was earlier used by the authors for validating their proposed damage diagnosis algorithm [4]. Figure 8 : Instrumentation set up – Single Crack Crack specimen Both the experimental specimens are excited near the centre of the beam with harmonic excitation of 10Hz. The acceleration time history responses are measured at the eight spatial locations as indicated in Fig. 8. The damage index based on SSA is estimated using Eqn. (1) for both the test specimens and the results are furnished in Fig. 10. The damage index corresponding to single crack experimental specimen shows a single peak at sensor 4, which coincides with the exact location of the actual crack. It is also evident from Fig. 10 that the damage index plot corresponding to two crack experimental specimen shows peaks at the spatial location of sensor 3 and sensor 6 clearly reflect the actual closing crack locations of the considered beam. Figure 9: Experimental Multiple Breathing Crack specimen [4] 0 1 2 3 4 5 6 7 8 9 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 two crack specimen (8 sensors) single crack specimen (8 sensors) single crack specimen (4 sensors) two crack specimen (4 sensors) Damage Index Sensor Nodes Figure 10 : Damage Index – Experimental Specimen – multiple breathing cracks