Modification of the Finite Element Methode (FEM) based on the different types spline shape function is an up-to-date strategy for numerical solution of partial differential equations (PDEs). This approach has an advantage that the geometry in Computer Graphics framework and approximation of fields of unknown quantities in FEM are described by the same technique. The spline variant of FEM is often called the Isogeometric Analysis (IGA). Another benefit of this numerical solution of PDEs is that the approximation of unknown quantities is smooth. It is an outcome of higher-order continuity of spline basis functions. It was shown, that IGA produces outstanding convergence rate and also appropriate frequency errors. Polynomial spline (Cp-1 continuous piecewise polynomials, p ≥ 2) shape functions produce low dispersion errors and moreover, dispersion spectrum of unbounded domains does not include optical modes unlike FEM based on the higher-order C0 continuous Lagrange interpolation polynomials.In this contribution, the B-spline (NURBS with uniform weights) shape functions in the FEM framework are tested in the numerical solution of free vibration of an elastic block. The main attention is paid to the comparison of convergence rate and accuracy of IGA with the classical Lagrangian FEM, Ritz method and experimental data. and Obsahuje seznam literatury