Roman Lewandowski

Dynamic analysis of structures with multiple tuned mass dampers

Abstract It is the purpose of this paper to analyse the possibility of reducing the vibrations of frame building structures with the help of multiple tuned mass dampers. Structures exposed to strong winds are considered. Excitation forces, which are functions of wind velocity fluctuations, are treated as random forces. The spectral density functions of wind velocity fluctuations are assumed as proposed by Davenport. The correlation theory of random vibration is used and the root mean squares of displacements and accelerations are determined. Several remarks, concerning the effectiveness of multiple tuned or mass dampers, are formulated from the results of calculation.

The Influence of Uncertainty of Design Parameters on Dynamic Characteristics of Structure with Dampers

Abstract. In this paper, the influence of the uncertainty of design parameters on the dynamic characteristics of structures with viscoelastic dampers mounted on them is considered. The fractional derivatives are used to describe the models of dampers. The uncertainty of their design parameters is introduced as an interval value. The lower and upper bounds of objective dynamic characteristics are obtained using the firstand second-order Taylor series expansion. Typical calculations are presented and compared with the results obtained using the vertex method.

Influence of elastic supports on non-linear steady-state vibrations of Zener material plates

The paper reports numerical results of analyses of steady-state harmonic vibrations of von Karman non-linear plates made from Zener material with various elastic support conditions. Influences of s...

Dynamic characteristics and frequency response function for frame with dampers with uncertain design parameters

ABSTRACT The influence of uncertain design parameters on dynamic characteristics and the frequency response function is considered in this paper. A structure with dampers modeled as a shear frame is analyzed. The dampers properties of dampers are described by fractional derivatives. The design parameters of the considered structure change only in a specified range and the interval analysis is taken into account in calculating the lower and upper bounds of dynamic characteristics. Several methods are used to obtain the limit values of objective functions: the vertex method and the method of approximation using the first- and the second-order Taylor series expansion. The vertex method is adopted as a comparative method. Two examples are presented in order to illustrate the considered methods. In the case of large uncertainties, the obtained results differ from those obtained by means of the vertex method. Therefore, a new method using the second-order Taylor series expansion is proposed. The method consists of a sequence of changes of only one parameter and requires much fewer combinations when the number of uncertain design parameters is high.