PSI - Issue 14

Sanjeev M Kavale et al. / Procedia Structural Integrity 14 (2019) 584–596 Sanjeev M. Kavale, Krishnaraja G Kodancha, Nagaraj Ekbote / Structural Integrity Procedia 00 (2018) 000–000

590

7

and CT specimens for different Poisson’s ratio with a/W = 0.50 and B/W = 0.50 is shown in Fig. 8. These figures indicate that the magnitude of T 11 / σ is increasing with the increase in Poisson’s ratio. It is also observed that the difference in T 11 / σ between center and surface for the specimen with higher Poisson’s ratio is more as compared to the specimen with lesser Poisson’s ratio. For both specimens, as the thickness increases a dip in the magnitude of T 11 is observed near the specimen surface. However for SENB specimen, peaking is dominantly observed at the center of the specimen, irrespective of the specimen thickness considered. But for CT specimen, as the thickness increases and Poisson’s ratio increases the peaking is shifting to surface than center.

0.9 (A)

0.4 (B)

 = 0  = 0.20  = 0.25  = 0.30  = 0.35  = 0.40  = 0.45

 = 0  = 0.20  = 0.25  = 0.30  = 0.35  = 0.40  = 0.45

0.3

0.8

0.2

0.7

T 11 / 

T 11 / 

0.1

SENB a/W=0.50 B=12.7mm

CT a/W=0.50 B=12.7mm

0.6

0.0

-6 -4 -2 0 2 4 6 8 10 12

-6 -4 -2 0

2

4

6

8 10

B in mm

B in mm

Fig. 8 Variation of T 11 along the crack-front for various Poisson’s ratio for a/W =0.50 and B/W =0.50 for (A) CT specimen and (B) SENB specimen

(A)

(B)

 = 0  = 0.20  = 0.25  = 0.30  = 0.35  = 0.40  = 0.45

 = 0  = 0.20  = 0.25  = 0.30  = 0.35  = 0.40  = 0.45

SENB a/W=0.50 B=12.7mm

CT a/W=0.50 B=12.7mm

1.6

1.6

1.4

1.4

1.2

1.2

1.0

1.0

0.8

0.8

Triaxiality Factor (h)

Triaxiality Factor (h)

0.6

0.6

-8 -6 -4 -2 0 2 4 6 8 10

-8 -6 -4 -2 0 2 4 6 8 10

B in mm

B in mm

Fig. 9 Variation of Stress Triaxiality Factor (h) along the crack-front for various Poisson’s ratio for a/W =0.50 and B/W =0.50 for (A) CT specimen and (B) SENB specimen

The variation in the K I and T 11 -stress across the thickness and varying Poisson’s ratio could be because of change in Stress Triaxiality Factor ( h ) along the crack front and the ligament. In the investigation done by Kodancha and Kudari (2010) on CT specimen, it is observed that the Stress Triaxiality Factor varies for different thickness and various a/W ratios. Similarly, in the present investigation also variation in Stress Triaxiality Factor is observed with thickness and different Poisson’s ratio. Fig. 9 indicates the variation of Stress Triaxiality Factor along the crack for a/W = 0.50, B/W = 0.50 and various Poisson’s ratio for CT and SENB specimen. Figures 10 and 11 indicate the variation of Stress Triaxiality Factor along the ligament for in plane (center of the specimen) and out of plane (surface of the specimen) conditions for a/W = 0.50, B/W = 0.50 and various Poisson’s ratio for SENB and CT