The interaction of anti-plane elastic SH waves with a periodic array of interface
cracks in a multi-layered periodic medium is analyzed in this paper. A perfect periodic structure
without interface cracks is first studied and the transmission displacement coefficient is obtained
based on the transfer matrix method in conjunction with the Bloch-Floquet theorem. This is
then generalized to a single and periodic distribution of cracks at the center interface and the
result is compared with that of perfect periodic cases without interface cracks. The dependence of
the transmission displacement coefficient on the frequency of the incident wave, the influences of
material combination, crack configuration and incident angle are discussed in detail. Compared
with the corresponding perfect periodic structure without interface cracks, a new phenomenon is
found in the periodic layered system with a single and periodic array of interface cracks.