PSI - Issue 66

Vivek Vishwakarma et al. / Procedia Structural Integrity 66 (2024) 381–387 Author name / Structural Integrity Procedia 00 (2025) 000–000

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The spatial binning approach, a method to aggregate and visualize spatial data, simulates the crack path. A bin size equal to the RMSE value was used in that direction. The AE data was binned only in the y and z-direction as it is a single crack problem, so data need not be binned in the x -direction. The crack path generated was then compared with the DIC data and shown in the Figure 4a. AE data was also capable of generating the 3D crack profile utilizing the same binning approach in the z -direction, as shown in Figure 4b. The bin size was selected based on RMSE values in

b

a Figure 4, a. Comparison of crack path by AE data and DIC. b. 3D crack profile

the particular direction. Further, the temporal binning strategy (TBA) was used to determine the crack length vs time. The implemented temporal binning approach provides a method for analysing the temporal evolution of acoustic emission activity in relation to crack growth. This technique involves discretizing the experimental time duration into uniform temporal bins. Within each bin, the AE events were aggregated, generating a discrete representation of AE activity as a function of time. A comparison of this temporal AE profile with independently measured crack length data obtained via DIC is made and shown in Figure 5. In this study, a temporal bin size of 100 seconds is used. This method is independent of bin size, provided sufficient amount of AE data is available in the bin. A monotonic constraint is imposed on the

Figure 5 Evolution and comparison of crack length by AE data and DIC for beam LRB33S

derived crack length to ensure physical consistency, reflecting the irreversible nature of crack growth. This constraint effectively filters spurious decreases in apparent crack length that might arise from noise or other non-crack-related AE sources. The TBA, coupled with the monotonic constraint, enables the estimation of crack length evolution over time, providing a quantitative assessment of the method's efficacy in monitoring crack growth. 4. Application in fatigue loading The applicability of the spatial and temporal binning approach, developed and validated under monotonic loading, was further investigated under fatigue loading conditions. The objective was to assess the method's performance in a more complex loading scenario involving cyclic crack opening and closing. Acoustic emission data acquired during