Fig. 6 Examples of the assessment of the present simulation for the cracked area plotted against cycles ratio due to the application of CAL having different stress amplitudes utilizing specimens with different surface configurations.
The results of the two virtual tests shown in Fig. 6 for the CSA of 432.5 MPa and 390 MPa are further considered in the form of\(\text{\ A}_{C}\) plotted against\(\ \frac{N}{N_{f}}\). For the same\(\ \frac{N}{N_{f}}\), the higher the stress amplitude the higher\(A_{C}\) is. For the same\(\text{\ A}_{C}\), the lower the stress amplitude the higher \(\frac{N}{N_{f}}\ \)is. The two points A and B in Fig. 5 are duplicate in Fig. 6. Figure 6 concludes that based on the results of the simulation of the CSA tests the\(\ \sum{\ \frac{N}{N_{f}\ }}\) in the TSL with L-H sequence,\(\ {=S}_{1\ },\ \) should be greater than 1 and in the case of H-L sequence\(\ \sum{\ \frac{N}{N_{f}\ }}\),\(\ {=S}_{2\ },\ \)should be less than 1.
However, Fig. 5 shows that the \(\sum\frac{N}{N_{f}\ }\) given by the simulation of the corresponding TSL test with the L-H sequence is slightly less than\(\ S_{1}\). Further, the\(\sum\frac{N}{N_{f}\ }\) corresponding to the TSL test with the H-L sequence is appreciably less than\(\text{\ S}_{2}\). In spite of points A and B having equal \(A_{C}\), the cracking damage configuration (CDC) of the specimen at point B due to the application of the CSA 432.5 MPa and that at point A due to the application of the CSA 390 MPa are different as discussed below.