Non-contact evaluation of the resonant frequency of a microstructure using ultrasonic wave

作     者：X. Kang X. Y. He C.J. Tay C. Quan 

作者机构：Department of Applied Mechanics Nanjing University of Science and Technology 210094 Nanjing China Institute of Engineering Mechanics Southeast University210096 Nanjing China Department of Mechanical Engineering National Universityof Singapore 9 Engineering Drive 1 117576 Singapore Singapore 

出 版 物：《Acta Mechanica Sinica》 (力学学报（英文版）)

年 卷 期：2010年第26卷第2期

页      面：317-323页

核心收录：

学科分类：07[理学] 08[工学] 070206[理学-声学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(10772086 and 10727201) the National University of Singapore(R-265-000-140-112) 

主　　题：Non-contact Microstructure· Resonant frequency Ultrasonic wave Image processing 

摘      要：This paper presents a novel non-contact method for evaluating the resonant frequency of a microstructure, Firstly, the microstructure under test is excited by ultrasonic waves. This excitation method does not impose any undefined load on the specimen like the electrostatic excitation and also this is the first actual use of ultrasonic wave for exciting a microstructure in the literature. Secondly, the amplitudes of the microstructure are determined by image edge detection using a Mexican hat wavelet transform on the vibrating images of the microstructure. The vibrating images are captured by a CCD camera when the microstructure is vibrated by ultrasonic waves at a series of discrete high frequencies （〉30 kHz）. Upon processing the vibrating images, the amplitudes at various excitation frequencies are obtained and an amplitude-frequency spectrum is obtained from which the resonant frequency is subsequently evaluated. A micro silicon structure consisting of a perforated plate （192 × 192 μm） and two cantilever beams （76 × 43 μm） which is about 4 μm thickness is tested. Since laser interferometry is not required, thermal effects on a test object can be avoided. Hence, the setup is relatively simple. Results show that the proposed method is a simple and effective approach for evaluating the dynamic characteristics of microstructures.