Sandwich beams offer designers a number of advantages, as the high strength to weightratio, flexibility, high bending and buckling resistances. Sandwich construction results higher natural frequenciesthan none sandwich constructions, also it developed an adaptive tuned vibration absorber. In the present work, the natural frequencies and mode shapes of the sandwich beam structure are calculated under different boundary conditions. Three models are created using MSC-PATRAN/NASTRAN software, 1D beam, 2D shell and 3D solid. The results for AL solid beam, CPVC solid beam, and AL-CPVC sandwich construction beam were obtained and compared with the analytical results. The results show a good agreement between the finite element models and analytical models for AL solid beam, CPVC solid beam with less than 2% error. For AL-CPVC sandwich construction beam the analytical solution is over predict the natural frequencies with 27% for the first mode and increases with increasing the number of modes to reach 40% at the fourth mode. The effect of material application and the boundary conditions are studied.