The different dynamical properties (phonon frequencies, elastic constants and Debye-Waller factors) of samarium hexaboride have been jointly treated with lattice dynamics modeling. An important influence of internal tensions on the dynamics of hexaborides has been established. The structural phase transition under hydrostatic pressure has been predicted based on our modeling. The first results of neutron diffraction studies of SmB₆ under pressures of up to 7 GPa are presented.