13th International Conference on Fracture June 16–21, 2013, Beijing, China -8- surface, fractography for foil specimens was investigated by scanning electron microscopy (SEM). All SEM images exhibited similar fracture surface appearances. Representative SEM images taken of specimens that failed during cyclic loading are shown in Fig. 7. These images show the complicated fracture surface appearance for crack growth within the Paris region with occasional striations visible. Fractography features also indicate a ductile, void rupture along with indications of transverse (through thickness) necking. Table 4. Overview of the experimental conditions and test results for the cyclic fatigue crack growth behavior 30 �m thick Ti. ID ��, MPa Corrected �Kmax, MPa m1/2 Corrected �Kmin, MPa m1/2 ai mm Ntot C m correlated with FEM results A-1 A-2 A-3 A-4 B-1 B-2 B-3 B-4 111 100 112 110 109 109 110 112 19.5 19.7 19.1 19.7 19.9 20.3 19.0 19.6 11.4 9.46 10.4 10.2 8.9 9.04 9.22 9.07 1.6 1.6 1.6 1.6 1.35 1.35 1.35 1.35 44,941 49,751 42,104 44,667 45,476 44,234 44,330 45,449 2.55E-13 8.62E-13 3.34E-13 9.25E-13 4.48E-13 2.31E-13 3.61E-13 4.84E-14 4.96 4.72 4.9 4.58 4.80 5.01 5.02 5.45 Figure 7. SEM fractography images fracture surfaces of a typical specimen subjected to tension-tension fatigue until failure. The fracture surface exhibited complicated fracture features including striations and transverse necking. 5.2 Similarity Analysis Incomplete self-similarity of higher crack growth rate for foils
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