PSI - Issue 18

A.P. Zakharov et al. / Procedia Structural Integrity 18 (2019) 749–756 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig.2. J-integral distributions as a function of applied stress level

The distributions of the governing parameter of the elastic – plastic crack-tip stress fields I n -integral as a function applied stress level in the full range of biaxial stress ratio are plotted in Fig.3. Opposite trend of I n -integral distributions as a function of the applied stresses with respect to J -integral is observed for both types of crack tip configurations. I n -integral is decreased with increasing applied stress level. As it follows from results presented in Fig.3 I n -integral values are very sensitive to the type of biaxial loading, therefore the plastic SIF also clearly depends on the biaxial loading conditions.

Fig. 3. Governing elastic – plastic parameter I n -integral distributions as a function of applied stress level.

Fig.4 illustrates results of comparative analysis of values of plastic SIF calculated for both small-scale and large-scale yielding. Plastic SIF for small-scale yielding ( K ssy ) and large-scale yielding ( K p ) were calculated by Eq.(2) and Eq.(8) respectively. Values of plastic SIF in Fig.4 are presented as a function of applied stresses for equibiaxial tension-compression ( η = -1) and equibiaxial tension ( η = +1) for both types of crack tip geometries. In Fig.4 solid lines correspond to the plastic SIF at large-scale yielding as well as dashed lines correspond to plastic SIF calculated for small-scale yielding. In the CCP with finite radius crack tip a significant difference between plastic SIF obtained for small-scale yielding ( K ssy ) and large-scale yielding ( K p ) is observed with respect to CCP with mathematical notch type crack. The plastic SIF distributions have the same character for both considered crack tip configurations with respect to J -integral distributions.