PSI - Issue 14

Digendranath Swain et al. / Procedia Structural Integrity 14 (2019) 207–214 Swain et al./ Structural Integrity Procedia 00 (2018) 000–000

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Fig.6. Applied stress vs strain data at various points are shown for (a) PT specimen-1 and (b) PT specimen-2. (c) and (d) shown the AE parameters obtained for PT specimen-1 and PT specimen-2. The nomenclature used in this figures are 1-just before yielding, 2- just before failure, 3-AE signals from the internal anomaly, and 4-visible crack in DIC strain field. Table 3. Summary of the data obtained with DIC for the SCT specimens such as failure stress, nominal strains away from crack, local strains near the crack tip, and overall inference during failure. (DIC image grabbing rate: 2.5 fps < 800 MPa & 7.5 fps > 800 MPa) Specimen name Failure Stress (MPa) Strain away from crack (%) Strains near crack-tip (%) Notable Inferences of failure SCT-1 1300 0.65 4.14 Failed during load hold SCT-2 1295 0.63 4.26 Failed during loading in progress Table 4. Summary of the data obtained with DIC for the PT specimens such as ultimate stress, average elongation, local peak strains in the gauge length, and overall inference during failure. (DIC image grabbing rate: 1 fps < 1000 MPa and 7.5 fps > 1000 Mpa) Specimen name Ultimate Stress (MPa) Avg. % Elongation Local peak strains (%) Notable Inferences 4. Concluding Remarks This paper demonstrates the advantages of interpreting failure behavior integrating AE, a qualitative NDT tool, with DIC, a quantitative optical tool. In SCT specimens, various phases of crack growth have been identified from the clear trend changes in the AE parameters which was having good agreement with DIC parameters. Similarly, in PT specimens AE signals corresponding to initiation of yielding and growth of an internal defect were identified agreeing with DIC strain data. The full-field macroscopic DIC observation combined with AE signals helped in understanding the nature of failure and material degradation to a satisfactory extent. Hence, in future such studies PT-1 PT-2 1472 1459 20 109 10.9 Failure through necking 2 Failure by crack initiation at ~1400 MPa