Linear dynamics of a sandwich beam (a plate of sandwich composition in one-dimensional cylindrical bending) bearing concentrated masses and supported by springs is described in the framework of the sixth order theory of multilayered plates. Analysis of the in#uence of a single inclusion and of a pair of identical inclusion upon vibrations of an in"nitely long beam is performed by the use of the Green function method. To construct the Green functions, a dispersion polynomial is derived and normal modes are obtained. Parameters of propagating low-frequency waves are checked against results available in the literature. Then the Green functions for #exural and shear vibrations of a beam excited by a point force or a point shear moment are considered. Attention is focused on a comparison of forced vibrations of homogeneous beams and beams bearing concentrated masses supported by springs. The role of interaction of dominant #exural waves with dominant shear waves near inclusions is discussed. Conditions of localization of #exural waves at these inhomogeneous are explored in respect of excitation parameters and parameters of sandwich composition. Radiated acoustic power is computed in the case of a homogeneous beam and in a trapped mode case to illustrate the importance of the localization e!ect for structural acoustics.