ωp.
Fig. 17(a) indicated that when ωp was constant and inclusion was stiffer than the medium, transientαηDSCF decreased with the reduction in elliptical axial ratio, gradually declined from 1.928 to 0.897. This demonstrated that at the inclusion stiffer than the medium, unlike steady-state αηDSCFalways less than 1, the transient incident aggravated the angular stress concentration. Moreover, the angular stress concentration as shape of inclusion approaching crack was more significant than that approaching circle. In Fig. 17(b), for the inclusion softer than the medium, transientαηDSCF increased with the decrease in the elliptical axial ratio, from 2.712 to 3.705. Numerical results demonstrated that for the inclusion softer than the medium, the angular stress concentration at shape of inclusion approaching circle was more significant than that when shape of inclusion approaching crack. This phenomenon was contrary to Fig. 17(a), indicated that the difference of material properties between the inclusion and medium affected the changes in transientαηDSCF with elliptical axial ratio.
Fig. 18 illustrated that when elliptical axial ratio andωp were constant, transientαηDSCF for the inclusion stiffer than the medium was always smaller than that for the inclusion softer than the medium. This phenomenon indicated that the angular stress concentration of the soft inclusion was more significant than that of the stiff inclusion, and the softer the inclusion was, the greater the possibility of failure at both ends of the minor axis. The value of transient αηDSCF in case 2 was smaller than that in case 3, which proved that the greater the difference in the material properties between the medium and inclusion, the more significant the dynamic stress concentration. This phenomenon was consistent with the changes of steady-stateαηDSCF .