On the characteristic freqencies of transverse vibration for a portable rotary cutter with an electlic motor (Part 2)

Abstract

The characteristic freqencies of the transverse vibration of a portable rotary cutter with an electric motor were caluculated as a function of beam length, its flexural rigidity, its weight per cm, the mass and effective mass moment of inertia at each end of the beam using a simplified free beam model as shown in Fig. 1.
Results obtained were as follows;
(1) The beam's length, flexural rigidity, weight per cm and moment of inertia of motor assembly affected greatly the natural freqencies, while mass at each end, and gyromoment of rotating disc or armature had little effect on them even thongh these values were varied by ±50% on the basis of measured values.
(2) The caluculated natural freqencies differed by about 5% from experimented data. As the model chosen was very simplified and incomplete. it was desirable to improve it further to know accurate natural freqencies in all cases or to take another step for analysis of portable rotary cutters.
(3) This simple caluculation method may be used to predct the approximate values of natural freqencies or to transfer them to desired positions for machines having multi-mass, -moment, -spring on a beam.