Fig. 5 Examples of the assessment of the present simulation for the cracked area plotted against number of loading cycles for two-step loading tests with low-to-high, O-A-B-C, and high-to-low, O-B-A-D, sequences compared with the corresponding behavior due to the application of CSA virtual tests having the two involved stress amplitudes 390 MPa, O-A-D\, and 432.5 MPa, O-B-C\; (a) and (b) present the behavior of two specimens with different surface configurations.
Figure 6 presents the results of \(A_{C}\) against \(\frac{N}{N_{f}}\)for four virtual CSA tests. The figure shows that for a given ratio of\(\text{\ \ }\frac{N_{1}}{{N_{f}}_{1}\ }\ \)in TSL tests with L-H sequence, the ratio \(\frac{N_{2}}{{N_{f}}_{2}\ }\) increases as the difference between the two involved stresses increases. With the H-L sequence, \(\frac{N_{2}}{{N_{f}}_{2}\ }\)decreases with an increase in that difference.