Directional-sensitive differential laser Doppler vibrometry for in-plane motion measurement of specular surface

Kusuma Agusanto; Gih-Keong Lau; Kun Wu; Ting Liu; Chuangui Zhu; Ling Yuan

doi:10.1117/12.2075845

4 March 2015 Directional-sensitive differential laser Doppler vibrometry for in-plane motion measurement of specular surface

Kusuma Agusanto, Gih-Keong Lau, Kun Wu, Ting Liu, Chuangui Zhu, Ling Yuan

Author Affiliations +

Proceedings Volume 9302, International Conference on Experimental Mechanics 2014; 93020V (2015) https://doi.org/10.1117/12.2075845
Event: International Conference on Experimental Mechanics 2014, 2014, Singapore, Singapore

Abstract

A new method for measuring in-plane vibration velocity of glossy and specular surface using differential laser Doppler vibrometer (LDV) is proposed in this work. A standard tangential LDV using similar differential configuration is only able to measure in-plane velocity of objects with rough surface, due to its inherent on-axis optical design that collects backscatter light along its optical axis. The proposed method adopts an off-axis detection scheme, in which the photodetector is decoupled from LDV, and placed along the dominant direction of the scattered light. For optimal placement, the bidirectional reflectance distribution function (BRDF) of the sample must be considered ideally, but in our measurement tests, the off-axis detection along the direction of specular reflection is sufficient to obtain good measurement results. Another advantage with this setup is that it also works with the objects with rough surface. Experimental works using the standard tangential LDV and a prototype of this method were conducted to measure the in-plane motion of four different samples representing rough, glossy and mirror-like surface. An electrodynamic shaker was used to provide the in-plane motion of the samples at three different frequencies. A single point axial vibrometer was used to validate the in-plane velocity of the measurement from both in-plane LDVs. Some preliminary results showed that the in-plane motion of the object with glossy and specular surface can be measured using the proposed method.

Citation Download Citation

Kusuma Agusanto, Gih-Keong Lau, Kun Wu, Ting Liu, Chuangui Zhu, and Ling Yuan "Directional-sensitive differential laser Doppler vibrometry for in-plane motion measurement of specular surface", Proc. SPIE 9302, International Conference on Experimental Mechanics 2014, 93020V (4 March 2015); https://doi.org/10.1117/12.2075845

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available