eigenfunction expansion technique. Zak and Williams [1] showed that the stress field singularity at the tip of a crack perpendicular to an interface or terminating at the interface is of order r −λ , where λ is the real part of the eigenvalue and depends on the elastic properties of the bi-material. Bogy [2] investigated the stress singularity of an infinite crack terminating at the interface with an arbitrary angle of different material components. Cook and Erdogan [3] used the Mellin transform method to derive the governing equation of a finite crack perpendicular to the interface and obtained the stress intensity factors (SIFs). The authors found that the power singularity of stress around the crack tip is not −1/2. Erdogan and Biricikoglu [4] solved the problem of two bounded half planes with a crack going through the interface. Wang and Chen [5] used photoelasticity to determine the stress distribution and the stress intensity factors of a crack perpendicular to the interface [6-8], and also used finite element to analyze cracks perpendicular to bimaterial in a finite elastic body. Chen [9] used the body force method to determine the stress intensity factors for a normal crack terminating at a bi-material interface. Chen et al.[10] used the dislocation simulation approach to investigate the crack tip parameters for a crack perpendicular to an interface in a finite solid. He and Hutchinson [11] also considered cracks approaching the interface at oblique angles. Lin and Mar [6] presented a finite element analysis of the stress intensity factors for cracks perpendicular to the bi-material interface. Chang and Xu [12] presented the singular stress field and the stress intensity factors solution for an inclined crack terminating at a bi-material interface. A theoretical description of the stress singularity at an inclined crack terminating at an anisotropic bi-material interface was proposed by Lin and Sung [13]. Wang and Stahle [14,15] used the dislocation simulation approach to investigate a crack perpendicular to and terminating at the Abstract The objective of the present work is to investigate the interaction between interfaces and cracks normal to and terminating at a metal/alumina interface. The behavior is analyzed by the determination of the J integral and the plastic zone at the crack tip using the three-dimensional finite element methods. The effects of the thickness of the metal/alumina were highlighted. The obtained results allow us to deduce mathematical relations, giving the variation of the J integral and the plastic zone as a function of the crack position and the bi-materials thickness.