PSI - Issue 39

Hithendra Karakampalle et al. / Procedia Structural Integrity 39 (2022) 711–721 Author name / Structural Integrity Procedia 00 (2021) 000–000

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maximum length of 37 mm; beyond this crack length, the plate was not able to hold the applied load. It may be noted that the definition of crack length encompasses the diameter of holes in the path of the crack as shown in Fig. 6; i.e., the crack length 2a denotes d+2l, where, l is the crack length from the surface of the hole. For the second part of investigation, the size of crack was varied up to 25 mm. For the third aspect of the study, an initial crack is assumed at location L2 and additional cracks were introduced at locations L1 and L3. The details of test cases are summarized in Table 2.

Table 2. Geometry of cracks CASE 1

CASE 2

CASE 3

S.No. 2a, mm S.No. 2a, mm

S.No. 2a, mm

S.No. 2a@L2, mm 2a@L1,L3, mm

1 2 3 4 5 6 7 8 9

0 7 8 9

12 13 14 15 16 17 18 19 20 21 22

22 23 24 25 26 27 28 29 30 31 37

1 2 3 4 5 6 7 8 9

0 6 7 9

1 2 3 4 5 6 7 8 9

7

0 7 9 0 7 9 0 7 9

11

10 11 12 13 14 15 16

11 13 15 17 19 21 23 25

9

11

11

10 11

10 11 12

10 11 12

11

Fig. 6. Definition of typical crack In all these studies, cracks were considered only at the first row, since it was observed during one of our previous works [Hithendra and Prakash (2021)] that the damaging effect of cracks in rows 2 and 3, are insignificant, compared to the ones in row 1. 2.2. Loads and Finite Element Model All the simulations were performed using ANSYS 19.0®, considering the plane stress and linear elastic conditions. With pin positions fixed in all degrees of freedom, a load of 14,400 N was applied at one end of the plate to create a remote stress of 80 MPa. For meshing the plate and the pin, PLANE183, a 2-D 8-node quadratic element was used with a 2 mm size. Near the cracks, a 0.025 mm edge sizing was applied. Contacts were defined using elements CONTA172 and TARGE169 with coefficient of friction 0.2. These mesh parameters were validated by comparing the theoretical values available for a finite width plate with center crack [Pilkey (2004)] with the results obtained from simulation. The difference was less than 3%, which validates the choice of parameters. Figure 7 shows the typical mesh generated, for case 2 with an 11 mm crack size.