Resonance properties of a froude pendulum with vibration of the axis of suspension (original) (raw)
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Romanian journal of Acoustics and Vibration, 2018
The study presented in this paper shows the results of simulation made on a rigid structure isolated with four simple friction pendulums. We created a model in SolidWorks that was used to find out how the pendulums radii and friction coefficients respectively the frequency of the excitation influences the structural response. It has also been found that the frequency of the structure does not increase with the frequency of excitation if the latter exceeds the natural frequency of the pendulum, but in the post-resonance domain it remains constant taking the value of the natural frequency of the system.
Comparison of the performance of friction pendulums with uniform and variable radii
Vibroengineering PROCEDIA, 2019
The paper presents research done by means of numerical simulation on a rigid structure isolated with friction pendulums. To this aim, we design friction pendulums which differ by the shape and dimension of the cylindrical sliding surface, respectively by the friction coefficients. Our target was to find out how the structure responds to a given excitation when the structure is equipped with diverse friction pendulums. A sinusoidal excitation with the frequency of 1 Hz is applied and the response in terms of displacements is captured. We found that the frequency of the structure does not change with the FP radius but the amplitude of the displacement is strongly dependent on this parameter. Because the circular and elliptical sections of the FP provide the structure with different natural frequencies, the resonance is achieved at other radii.
RESPONSE OF A STRUCTURE ISOLATED BY FRICTION PENDULUMS WITH DIFFERENT RADII
Annals of the "Constantin Brancusi" University of Targu Jiu, Engineering Series, 2018
This paper presents simulations that highlight the influence of the friction pendulum radius on the behavior of isolated structures. A model was created in SolidWorks, which is employed to find out the structural response. The excitation in term of displacements, ensured by a feature of the software program, follows a sine function. The study has shown the frequency evolution with the radius increase, along with the displacement of the isolated structure.
Autoparametric vibrations of a nonlinear system with pendulum
Mathematical Problems in Engineering, 2006
Vibrations of a nonlinear oscillator with an attached pendulum, excited by movement of its point of suspension, have been analysed in the paper. The derived differential equations of motion show that the system is strongly nonlinear and the motions of both subsystems, the pendulum and the oscillator, are strongly coupled by inertial terms, leading to the so-called autoparametric vibrations. It has been found that the motion of the oscillator, forced by an external harmonic force, has been dynamically eliminated by the pendulum oscillations. Influence of a nonlinear spring on the vibration absorption near the main parametric resonance region has been carried out analytically, whereas the transition from regular to chaotic vibrations has been presented by using numerical methods. A transmission force on the foundation for regular and chaotic vibrations is presented as well.
Investigation of oscillations of platform on isotropic supports excited by a pendulum
E3S Web of Conferences
Within the framework of a flat model, steady-state modes of motion of a system composed of a platform on isotropic elastic-viscous supports, a shaft on a platform, and a pendulum freely mounted on a shaft are investigated. The developed methodology was used in the studies, based on the energy method, the theory of bifurcations of motions, and the idea of a parametric solution to the problem. All steady-state modes of motion were found. It is established that these are modes of the pendulum jamming. Each mode is characterized by a corresponding jamming frequency. Depending on the velocity of rotation of the shaft, there may be one or three possible jamming frequencies. When there is only one jamming frequency, the corresponding mode of motion is globally asymptotically stable. When there are three jamming frequencies, locally asymptotically stable modes with the smallest and highest jamming frequencies of the pendulum. The smallest jamming frequency of the pendulum is close to resona...
Dynamics and Entropy Analysis of a Frictionally Loaded Pendulum
Entropy
We use friction to simultaneously damp and excite a pendulum system. A Froude pendulum attached to a suspension shaft is subjected to a frictional load. We investigate two types of response of the system: regular and chaotic responses, depending on the excitation frequency. A transient chaotic solution was also obtained. We identify the motions using phase portraits, Poincaré maps, and Fourier spectra. Finally, the composite multiscaled entropy was estimated for the specified cases to confirm the preliminary classification.