Functionally graded materials(FGMs)can be used as an interlayer.The interlayer connects two homogeneous materials and slows mutations in material properties,owing to the variability of parameters and microstructure.In this numerical simulation,a bond-based peri-dynamic(PD)model was used to perform dynamic fracture analysis of a continuous beam and a sandwiched structure with an FGM interlayer.Some simulation results of two convergence studies,which include grid refinement(m-convergence)and the reducing radius of PD horizon(δ-convergence),were discussed.Under a four-point bending load,the propagation behaviors of single pre-crack in the continuous beam with the FGM interlayer at different locations are sim-ulated to compare with the experimental results.For the sandwiched structure,the problems of a single crack and double cracks were considered.The numerical results show that the crack can deflect toward areas where the energy release rate is low.Additionally,the crack on the weak side for symmetric cracks only has fracture behavior,and if the double cracks are asymmetrical,all these cracks have fracture behaviors and propagation of the initial crack in the stiff region has a higher sensitivity than in the compliant region.