Mechanical Vibrations - Unesp...Mechanical Vibrations Prof. Paulo J. Paupitz Gonçalves Viscous...
Transcript of Mechanical Vibrations - Unesp...Mechanical Vibrations Prof. Paulo J. Paupitz Gonçalves Viscous...
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Mechanical Vibrations
Prof. Paulo J. Paupitz Gonçalves
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Viscous Damping
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Example of Application
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Free Vibration with Viscous Damping
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Free Vibration with Viscous Damping
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Critical Damping and Damping Ratio
Critical Damping
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Damping Ratio
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Underdamped Case
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Underdamped Case
Damped Natural Frequency
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Damped Natural Frequency
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Underdamped Case
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Underdamped Case
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Critically damped system
= 0
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Overdamped system
> 0
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Overdamped system
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Damped Vibration
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Damped Vibration
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Logarithmic Decrement
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Logarithmic Decrement
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Logarithmic Decrement
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Logarithmic Decrement
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Logarithmic Decrement
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Logarithmic Decrement
If damping is small
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Generalization
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Generalization
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ExampleThe free response of the damped single degree of freedom with mass of 2 kg is recorded to be of the form given in figure below. A static deflection test is performed and the stiffens is determined to be 1.5 x 103 N/m. The displacements at time t
1 and t
2 are measured to
be 9 and 1 mm, respectively. Calculate the damping coefficient.
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Example
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Another ExampleDetermine the natural frequency, damping ratio and damped natural frequency
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Another Example
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Another Example
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Another Example
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Another Example