Advanced possibilities of using the finite element method (FEM) in the process of designing a mobile chipper were presented. The usefulness of vibration analysis with FEM in assessing the stability of a structure subjected to forces of variable and undetermined frequency was demonstrated. Based on hybrid analytical and numerical calculations, a , the proper accuracy of the calculations was shown and justification of using FEM to calculate the structure loaded with periodically changing forces was confirmed. Advanced possibilities of using the finite element method (FEM) in the process of designing a mobile chipper were presented. The usefulness of the FEM analysis of vibrations in assessing the stability of a structure subjected to variable and unsteady frequency excitation was demonstrated. On the basis of the hybrid calculations - analytical and numerical, the proper accuracy of the calculations was demonstrated and the purposefulness of using the FEM method for the calculations of the structure loaded with periodically changing forces was confirmed.