where x is the distance from the crack center in the plane of the crack, and for plane stress, and for plane strain. The dimensionless functions and are derived in the Appendix. It is noticed here that and are even functions of , and are complex-valued. In the static limit of , one has . Thus, Eq. (5) reduces to the well-known result for a Griffith crack under static loading, e.g., Refs.  and .