13th International Conference on Fracture June 16–21, 2013, Beijing, China -15- Figure 38. Stress triaxiality evolution at 10/s Figure 39. Failure locus at 10/s Figure 38 shows stress triaxiality evolution curves of shear, tension, notched tension and punch under dynamic loading. We can observe that stress triaxiality of each test remains stable during loading process. Thus we can directly use the average value of stress triaxiality of each type of test. Calculation of stress triaxiality is referred to average stress triaxiality formulation Eq. (3). Table 5 summarizes the result of each test. Table 5. Equivalent failure strain, Average stress triaxiality Test type Shear Tension Notched-tension Punch Average stress triaxiality 0.01 0.33 0.39 0.66 Equivalent failure strain 0.056 0.406 0.482 0.532 Quadratic polynomial fitting of four base points is plotted in Fig. 39. 9. Conclusions and Discussions Consequently, we obtained failure locus in the space of equivalent plastic failure strain and stress triaxiality under static loading and dynamic loading. From Fig. 40, we can observe significant different failure locus between static loading and dynamic loading. Figure 40. Failure locus under static loading and dynamic loading 0.0 0.2 0.4 0.6 -0.2 0.0 0.2 0.4 0.6 0.8 0.0 0.2 0.4 0.6 -0.2 0.0 0.2 0.4 0.6 0.8 Stress triaxiality Equivalent plastic strain Simple shear Uniaxial tension Notched tension Punch 0.0 0.2 0.4 0.6 0.8 0.0 0.2 0.4 0.6 Linear Quadratic polynomial Shear Tension Notched tension Punch Equivalent failure strain Stress triaxiality 0.0 0.2 0.4 0.6 0.8 0.0 0.5 1.0 1.5 Equivalent plastic failure strain Stress triaxiality Quasi static Dynamic
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