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

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10

factor is reducing as B/W increases for a given Poisson’s ratio. Also it is evident from the Fig. 13 that the magnitude of normalized T 11 -Stress for both specimens is reducing as B/W increases for a given Poisson’s ratio. However, from Fig. 14, it can be observed that the value of magnitude of normalized T 33 -Stress for both specimens is increasing as B/W increases for a given Poisson’s ratio. An effort has been put in the current research to create polynomials for finding out the magnitudes of ������ / √ and corresponding T 11(max) / σ and T 33(max) / σ for various B/W and Poisson’s ratio and a/W = 0.50 without complex FE analyses. An open source software “CADRE Regression” is used to generate the polynomials. Below is the generated polynomial for finding out maximum normalized SIF.

K

(max) 

I

N A T .

(5)

a  





T

2

3    and

1

N



Where,

For CT specimen,

1

         

         

W B

  

  

0.342467 - 1.275597 2.060686 - 1.782613 0.064951 0.561014 - 0.904347 0.127380 - 0.142176 - 0.249075 0.121901 - 0.265584 0.097456 0.186438 - 0.107239 1.464148

A A A A

     

     

     

     

0

2

W B W B

1

     

     

A





2

3

3

For SENB specimen,

1

         

         

W B

  

  

0.351684 0.135487 - 1.327220 - 1.797420 0.202059 - 0.012602 0.626603 0.194610 - 0.080166 0.222710 - 0.017156 0.266900 0.002592 - 0.004726 - 0.019745 1.386217

A A A A

     

     

     

     

0

2

W B W B

1

     

     

A





2

3

3

The generated polynomial formulation is validated with the FE analysis done by Kudari and Kodancha (2014 and 2017). Maximum deviation of 1.33% and 4.12% is observed for CT specimen and SENB specimen respectively. The formulations are also validated with the available experimental results. Katanchi et al. (2017) have done experimental study on NiTi alloy. The authors have considered a CT specimen of W = 12mm, a = 6mm and B = 6mm with Poisson’s ratio, = 0.33. The fracture load observed was P = 1980N and critical Stress Intensity Factor is K I = 984.963 √ (31.15 √ ). The value of SIF obtained through Eq. 5 is 903.112 √ (28.56 √ ). An error of 8.31 % is observed between the experimental value and SIF obtained through formulation generated. Shlyannikov et al. (2014) have done experimental study on Steel, which had Young’s Modulus E = 196.363 MPa and Poisson’s Ratio ν = 0.30. The authors have considered SENB specimen with W = 20mm and B = 10mm. The fracture load observed was P = 9250N and critical Stress Intensity Factor is K I = 1818.15 √