Dynamic stress intensity factors around two parallel cracks in an infinite-orthotropic plane subjected to incident harmonic stress waves

The time-harmonic problem of determining stresses around two parallel cracks in an infinite orthotropic plane is studied. Incident stress waves impinge on the two cracks normal to their surfaces. The Fourier transform technique is used to reduce the boundary conditions to four simultaneous integral equations which are then solved by expanding the differences in the crack surface displacements in a series. The unknown coefficients in the series are calculated using the Schmidt method. Numerical calculations are carried out for the dynamic stress intensity factors in a boron-epoxy composite material, a carbon fiber reinforced plastic, a modulite II graphite-epoxy composite and an isotropic material. (C) 1997 Elsevier Science Ltd.