Functionally Graded Viscoelastic Artificial Boundary Layer In Time Domain Analysis Of Elastic Waves

In this paper, the concept of functionally graded (FG) viscoelastic artificial boundary layer is proposed for the numerical simulation of elastic waves. The governing equation of longitudinal wave in rod composed by elastic rod and FG viscoelastic rod is solved by Wentzel-Kramers-Brillouin method. The variation of material property in FG viscoelastic rod is obtained by no reflecting condition. Based on the analytical results, the setting of FG viscoelastic artificial boundary in the numerical simulation is recommended and applied in two examples, namely longitudinal wave excitation in an infinite rod and local excitation in an infinite half space. Numerical results show that the use of FG viscoelastic boundary should decrease the error caused by artificial boundary. These methods should be expanded in the numerical simulation of wave in other infinite structures.