Experimental Measurement, Theoretical Analysis and Numerical Calculation of Transient Wave Propagation of Displacement and Strain
Date Issued
2011
Date
2011
Author(s)
Chang, Chun-Kai
Abstract
Recently, piezoelectric film(PVDF) and fiber Bragg grating(FBG) are usually investigated by researcher. We use the FBG with power modulated sensing method to measure strain and displacement of the structure, and compared the sensing results with other sensors. Also, we investigate and discuss the dynamic measurement ability of the three-dimensional FBG measurement system. Then, PVDF can be used to measure pressure and dynamic external force history and has many advantages such as light, thin, excellent dynamic measurement ability and easy to adhesive on the object surface. In this thesis, we establish a measurement method to measure the dynamic force history on thin plate structures.
We can use the force history to conduct theoretical analysis and numerical calculation of finite element method(ABAQUS) then obtain the results of transient wave propagation within the structure. In theoretical analysis, we use the normal mode method and the Laplace transform method to calculate the results of transient wave propagation within the structure. For the Laplace transform method, it’s difficult to derive the inversion in transform domain. Therefore, we use the Durbin numerical inversion method to inverse the solution in transform domain and the inversion can be easier and more efficient. Besides, we use the exact solution determined by normal mode method to compare with the solution determined by Laplace method. It’s not easy to obtain the theoretical solution of transient wave propagation within the structure in most of engineering structure issue, thus, we can use the finite element method to estimate it. Finally, we compare the transient response of theoretical analysis, finite element method and experimental measurement to verify the accuracy of experimental measurement.
Subjects
fiber Bragg grating
piezoelectric film
finite element method
power modulated sensing method
transient wave propagation
force history
normal mode method
Laplace transform method
numerical inversion of Laplace
Type
thesis
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