EFFECT OF NONLINEAR TRIMMER LINK OF TWO-MASS DYNAMIC ABSORBER TO ITS EFFICIENCY UNDER HARMONIC EXCITATION WITH UNSTABLE FREQUENCY
The stationary oscillations of a single-mass protected structure, equipped with two-mass nonlinear dynamic absorber, under harmonic excitation are considered. It is assumed that the soft absorber nonlinearity is associated with the variability of the trim mass. To determine the motion of the system, the oscillations of the masses are expanded in a series of orthogonal Chebyshev polynomials. In analyzing the behavior of the protected structure, it is assumed that the frequency of the exciting force is unstable. It is shown that the presence of non-linearity in the soft type trimmer link absorber increases (up to 20 %) the efficiency of vibration isolation and significantly (about half) reduces vibrations of the trim mass.