Issue 78

A. Zakharov et alii, Fracture and Structural Integrity, 78 (2026) 260-274; DOI: 10.3221/IGF-ESIS.78,16

8*10 -2 ), the J-integral becomes a monotonically increasing function of the applied stresses over entire range 0.1 ≤ ( σ / σ 0 ) ≤ 0.4. Furthermore, for σ / σ 0 is more than 0.2, the J-integral distributions differ increasingly as a function of biaxial stress ratio. Fig.6 illustrates the effect of the biaxial stress ratio on the J-integral distributions over the range of applied stress levels considered. The results indicate that, for all crack-tip distances considered, the J-integral is independent of the biaxial loading type when σ / σ 0 ≤ 0.15. At higher stress levels ( σ / σ 0 > 0.15) the J-integral values under equibiaxial tension-compression ( η = -1) are lower than under equibiaxial tension ( η = +1). Over the entire range of applied stress levels considered, the J-integral distributions exhibit opposing trends as a function of the biaxial stress ratio for the MN and FRC crack-tip configurations. For the CCP with FRC crack tip shape the J-integral distributions decrease steadily as the biaxial stress state is transitioning from equibiaxial tension-compression ( η = -1) to equibiaxial tension ( η = +1).

Figure 6: J-integral distributions as a function of biaxial stress ratio. Fig. 7 presents the plastic SIF versus biaxial stress ratio over the range of applied stress levels studied. In contrast to the J-integral results shown in Fig. 6, the plastic SIF shows greater sensitivity to the biaxial stress ratio across the entire range of the applied stresses levels examined, and this effect remains stable with respect to the stress level. Furthermore, the results in Fig. 7 indicate that the crack-tip radius of curvature does not significantly affect the plastic SIF distributions in the CCP. For both MN and FRC crack-tip configurations, the plastic SIF decreases monotonically as the biaxial stress state changes from equibiaxial tension-compression ( η = -1) up to equibiaxial tension ( η = +1). As expected, due to the stress concentration at the crack tip the plastic SIF values for the MN are higher compared to the plastic SIF for CCP with crack tip with the FRC at the same nominal applied stress level.

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