PSI - Issue 59

Bernadett Spisák et al. / Procedia Structural Integrity 59 (2024) 3–10 B. Spisa ´ k et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Table 2. Fitted values of the parameters of equation (2). minimum

maximum

average

1T

0.5T

0.25T -0.225 1.145 -4.412 3.010 -1.639

0.16T -0.225 1.145 -4.412 3.010 -1.639

1T

0.5T

0.25T -0.103 1.848 -2.897 4.459 -1.121

0.16T -0.083 1.836 -2.632 4.425 -1.026

1T

0.5T

0.25T -0.164 1.497 -3.654 3.735 -1.380

0.16T -0.153 1.431 -3.508 3.589 -1.325

-0.151 0.819 -3.520 2.367 -1.345

-0.212 1.137 -4.229 2.983 -1.574

-0.046 1.427 -2.207 3.622 -0.897

-0.102 1.766 -2.872 4.280 -1.110

-0.098 1.123 -2.863 2.994 -1.121

-0.157 1.451 -3.551 3.631 -1.342

b c d e

f

Fig. 5. Surface fitted to the K-F curves of the hybrid 0.5T specimen.

To check the appropriateness of the resulting formula, the values of the stress intensity coefficient were determined for each dimension, where the force values obtained from the simulation were used as input parameters. Then, the values of the stress intensity factor determined from the simulation and the formula were taken and the percentage difference between them was calculated and compared with the result from the simulation. For each dimension, Table 3 shows for which a/W ratio had the largest deviation.

Table 3. Validation of formula. Parameters

1T 0.8

0.5T

0.25T

0.16T

0.8

0.8

0.8

a/W

K simulation

0.2842 0.2797 -1.59%

0.4019 0.3955 -1.59%

0.5684 0.5593 -1.59%

0.7105 0.6991 -1.60%

K formula

Percentage deviation

The table shows that the largest difference is only 1.6%. Further analysing the data, Figure 6 illustrates the percentage difference in stress intensity factors as a function of the a/W ratio for the 0.5T specimen, determined by formula and simulation. It clearly shows that the values determined by the formula underestimate the results from