New possibilities for vibration-amplitude measurement by heterodyne laser vibrometer

2000 ◽  
Vol 43 (2) ◽  
pp. 140-143
Author(s):  
V. G. Atavin ◽  
A. A. Mokhnatov ◽  
Yu. V. Khudyakov
Keyword(s):  
Vibration Amplitude ◽  
Laser Vibrometer ◽  
Amplitude Measurement

Improved holographic method for vibration amplitude measurement from nano to microscale

2014 ◽  
Author(s):  
Pavel Psota ◽  
Vít Lédl ◽  
Roman Doleček ◽  
Jan Václavík ◽  
Václav Kopecký
Keyword(s):  
Vibration Amplitude ◽  
Holographic Method ◽  
Amplitude Measurement

Multiple Mode Spatial Vibration Reduction in Flexible Beams Using H2- and H∞-Modified Positive Position Feedback

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Ehsan Omidi ◽  
S. Nima Mahmoodi
Keyword(s):  
Cantilever Beam ◽  
Vibration Amplitude ◽  
Vibration Suppression ◽  
Controller Design ◽  
Flexible Structures ◽  
Laser Vibrometer ◽  
Beam Vibration ◽  
Spatial Vibration ◽  
Positive Position Feedback ◽  
Position Feedback

This paper develops H2 modified positive position feedback (H2-MPPF) and H∞-MPPF controllers for spatial vibration suppression of flexible structures in multimode condition. Resonant vibrations in a clamped–clamped (c–c) and a cantilever beam are aimed to be spatially suppressed using minimum number of piezoelectric patches. These two types of beams are selected since they are more frequently used in macro- and microscale structures. The shape functions of the beams are extracted using the assumed-modes approach. Then, they are implemented in the controller design via spatial H2 and H∞ norms. The controllers are then evaluated experimentally. Vibrations of multiple points on the beams are concurrently measured using a laser vibrometer. According to the results of the c–c beam, vibration amplitude is reduced to less than half for the entire beam using both H2- and H∞-MPPF controllers. For the cantilever beam, vibration amplitude is suppressed to a higher level using the H2-MPPF controller compared to the H∞-MPPF method. Results show that the designed controllers can effectively use one piezoelectric actuator to efficiently perform spatial vibration control on the entire length of the beams with different boundary conditions.

Quantitative Vibration Amplitude Measurement Using Stroboscopic Phase Shifting ESPI

2006 ◽  
Vol 321-323 ◽  
pp. 95-98 ◽  
Author(s):  
Hyun Chul Jung ◽  
Koung Suk Kim
Keyword(s):  
Vibration Amplitude ◽  
Natural Frequencies ◽  
Measurement Techniques ◽  
Phase Shifting ◽  
Mode Shapes ◽  
Ansys Analysis ◽  
Amplitude Measurement ◽  
Stroboscopic Illumination ◽  
Square Plate ◽  
Optical Vibration

The stroboscopic phase shifting ESPI (SPS-ESPI), one of the optical vibration amplitude measurement techniques, is presented. Although the general PS-ESPI can be used for quantitative deformation measurement of the object, this technique cannot measure the vibration amplitude with itself only. The phase change due to the vibration of the object cannot be calculated with general PS-ESPI correctly. Therefore, in order to solve this problem, the stroboscopic illumination must be introduced to the general PS-ESPI. This can be done by using a device called as AOM (Acousto-Optic Modulator). In this paper, SPS-ESPI is applied to measure the vibration amplitude of the square plate whose all edges were fixed. The natural frequencies and mode shapes are analyzed by using ANSYS. And the results obtained by using SPS-ESPI technique are compared with that of the ANSYS analysis. The vibration amplitude is measured by using SPS-ESPI quantitatively.

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