• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.408-414
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• 2001

The structural characteristics of the stiffened double cylinder was investigated through experiment and analysis. The outside cylinder was excited with piezoelectric actuator and the mode shape of the cylinder with stiffening T frame was obtained by using holographic interferometry. Finite element method was applied for further modal investigation of the stiffened cylinder. The experimental results showed that the mode shape of cylinder was dependent on the exciting frequencies and the T frame showed salient effect of damping at most of the resonent frequencies. In particular frequencies, the T frame worked as a transmitter. FFM showed similar results with the experiments. This paper showed that the laser-based method such as holographic interferometry is well suited for investigation of the whole-field mode shapes and FEM has good performance to estimate the medal characteristics of the mechanical structure.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.130-135
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• 2000

In this study the vibration behavior of the stiffened double cylinder was experimently analyzed. Due to the complex structure of the double cylinder the outside cylinder frequency responses to the exciting forces applied on various posi-tions were analyzed by using spectrum analyzer in conjunction with an accelerometer and the natural frequencies were obtained. The technique of time-averaged holographic interferometry is applied to study the vibration characteristics of outside cylinder with stiffening T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. however the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. However the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame seemed to behave as a transmitter. In addition it has been successfully demon-started that optical method such as holographic interferometry is well suited for the identification of mode shapes. They can give us a whole-field non-contact measurement instead of the point-wise measurement by accelerometer in classical modal testing.