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Dvě rovnice popisjící kyvadlový tlumič
Fischer, Cyril ; Náprstek, Jiří
The pendulum damper modelled as a two degree of freedom strongly non-linear auto-parametric system is investigated using two approximate differential systems. Uni-directional harmonic external excitation at the suspension point is considered. Semi-trivial solutions and their stability are analyzed. The thorough analysis of the non-linear system using less simplification than it is used in the previous paper is performed. Both approaches are compared and conclusions are drawn.
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Rezonanční chování kulového kyvadlového tlumiče
Fischer, Cyril ; Náprstek, Jiří
The pendulum damper modelled as a two degree of freedom strongly non-linear auto-parametric system is investigated using two approximate differential systems. Uni-directional harmonic external excitation at the suspension point is considered. Semi-trivial solutions and their stability are analyzed. The thorough analysis of the non-linear system using less simplification than it is used in the previous paper is performed. Both approaches are compared and conclusions are drawn.
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Dynamické chování nosníku s přdpjatou strunou - vliv útlumu
Fischer, Cyril ; Frýba, Ladislav
The beam with an axial force is coupled by an elastic layer of Winkler type with the pretensiled string. It is subjected to a row of moving forces. The theoretical model corresponds to a prestressed bridge. The concrete bridges of this type are the most spread types appearing on both the road and railway bridges of small and medium spans. The governing equations form a coupled set of partial differential equations that are solved using the Fourier and Laplace integral transformations for the undamped case. The numerical solution is examined for the damped case.
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Bezmaticová formulace stochastické Newmarkovy metody
Fischer, Cyril
A response of an arbitrary discretized system to the random movement has been solved in probabilistic terms. The excitation has been defined as a combination of the time modulated band limited stationary random processes approximating the evolutionary power spectra of a true seismic record. The solution is based either on the modified version of the stochastic Newmark method or on the spectral differential decomposition of the excitation. Special attention has been paid to the applicability of the methods to the sparse problems, especially to their matrix-free formulation.
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