PSI - Issue 14

Sameerkant Behera et al. / Procedia Structural Integrity 14 (2019) 112–118 Sameerkant Behera, S. K. Sahoo, Lokesh Srivastava, A. S. Srinivasa Gopal / Structural Procedia 00 (2018) 000 -000

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Fig. 8. Grid mapping of full scale composite pressure vessel Keeping ultrasonic attenuation in to consideration, test dB requirement at different station has been finalised based on reference thickness blocks. Figure 9 represents set dB requirements in axial directions right from one end to other end of the full scale composite pressure vessel.

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Fig. 9. Attenuation dB w.r.t axial grid points

5. Results and Discussion As per grid mapping mentioned in figure 8, testing has been carried out. At certain grid points, wherever signal loss has been observed, additional dB has been pumped (in gain) to get more than 90% of the full scale height. Also fine grid mapping has been done adjacent to high dB signal loss points so as to get exact area showing loss of signal. Ultrasonic response in terms of additional dB requirements has been measured and represented in figure 10. Thick line trapezium represents high dB loss in order of 10-20 dB and thin line trapezium represents 0-10dB loss.

Fig. 10. dB loss/ultrasonic response for full scale composite pressure vessel.