Processing the response signals by using the random decrement technique, a unique corresponding to each mode is obtained, which represents a free vibration response of the structure.

In this paper the free vibration response of rotor bearing system is collected via varing the support stiffness by means of characteristics of balancing machine changing support stiffness in rotor balance.

Introducing six degrees of freedom the stiffness matrix of the complex system with arbitrary arrangement of piling is derived. Dynamic analysis is made using the free vibration response for multi-degree of freedom under initial conditions.

The estimation methods of damping factor of bellows under noise environment by free vibration response were presented. The wavelet transform was used to reduce the effect of environ- mental noise.

Closed form solutions are presented for the nonlinear free vibration response and for the responses under uniformly distributed static and step function loads.

Nonlinear free vibration response and the response under uniformly distributed static and step function loads are obtained.

The slowly-variant-system is defined and analyzed in this paper and the nonlinear relationship between its instantaneous parameters and the instantaneous amplitude and frequency of its free vibration response is established.

The finite element method in conjunction with first order perturbation technique have been employed to obtain the second order statistics of free vibration response of composite laminated plates with random material properties.

The free vibration response of the log was observed in the oscilloscope.

A new technique called Random decrement Technique (Randomdec) is used to accurately measure the natural frequency and damping ratio of a structure subjected to unknown random excitation such as ocean waves.The major advantage of the Randomdec is that it requires only measurements of the dynamic response and not the random excitation causing the response.A brief, rather intuitive explanation of the principles of the Random Decrement Technique is presented and the test procedure and results are described.Investigation...

A new technique called Random decrement Technique (Randomdec) is used to accurately measure the natural frequency and damping ratio of a structure subjected to unknown random excitation such as ocean waves.The major advantage of the Randomdec is that it requires only measurements of the dynamic response and not the random excitation causing the response.A brief, rather intuitive explanation of the principles of the Random Decrement Technique is presented and the test procedure and results are described.Investigation is completed on a 1/14 scale offshore platform model which is mounted on four pipe piles driven into the ground.The random excitation is simulated by hammer hit in experiment with the model.The response signals are measured by accelerometer and recorded on tape.Processing the response signals by using the random decrement technique, a unique corresponding to each mode is obtained, which represents a free vibration response of the structure.Finally, the natural frequencies and damping ratios of the structure can be found from these signatures by logarithmic decrement method.

This paper presents the analysis method of complex vibration of open piling pier with rubber fender due to ship impact during the berthing maneuvers. The traverse round of ship and damping effect are considered. Introducing six degrees of freedom the stiffness matrix of the complex system with arbitrary arrangement of piling is derived. Dynamic analysis is made using the free vibration response for multi-degree of freedom under initial conditions. Dynamic resisting force of pile and impact force are solved...

This paper presents the analysis method of complex vibration of open piling pier with rubber fender due to ship impact during the berthing maneuvers. The traverse round of ship and damping effect are considered. Introducing six degrees of freedom the stiffness matrix of the complex system with arbitrary arrangement of piling is derived. Dynamic analysis is made using the free vibration response for multi-degree of freedom under initial conditions. Dynamic resisting force of pile and impact force are solved by mode-superposition method.

The stability of high speed rotor bearing system is analysed by means of experimental modal analysis method.By this method,the information of system are synchronously sampled while rotor system is excited by a pulse force and,then,the stability of rotor system is evaluated by the criterion of logarithmic attenuation ratio according to the free vibration signals included within response information.The result shows that the excited free vibration response signals at the places far from exciting spots...

The stability of high speed rotor bearing system is analysed by means of experimental modal analysis method.By this method,the information of system are synchronously sampled while rotor system is excited by a pulse force and,then,the stability of rotor system is evaluated by the criterion of logarithmic attenuation ratio according to the free vibration signals included within response information.The result shows that the excited free vibration response signals at the places far from exciting spots include only the lowest order mode and the system damping in critical condition tends to make the system stable.