In this paper

the superimposing principle and the theory of Mellin transforms are used to reduce the controlling equations and boundary conditions of linear cracks intersecting hole into dual integral equations in an infinite elastic body. With finite Hilbert transforms

the dual integral equations can be reduced into a Fredhole integral equation of the second kind which is related to S(t2 ). The dynamic stress intensity factor can be expressed with the solution of integral equation and its numerical results in obtained. In the particular case

the numerical results are the same as those in reference[2] . the intensity factor decreases with the propagation of cracks. With experiments

the propagation velocity of these linear cracks are measured.