The natural frequencies of vibration for a portable rotary cutter with an electric motor were calculated by numerical calculation procedure using two shimplified models.
The models are freely suspended and consist of two beams supported at 5 points with each other. In both models, the first beam has 5 mass on it and mass moment of inertia, gyromoment at each end. The second beam is uniform and connected with the first beam at 5 points, The programing and calculation by electronic computor are so easy that this numerical calculation procedure seems to be one of the convenient methods for calculation of natural and forced transverse vibration for double-beam system which have many mass, mass of inertia, springs of supprting points,
The calculated secondary natural frequencies differed by about 5% from measured dear. As the models chosen are incomplete, it is desirable to improve them further for practical use.