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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A New Approach of DIC on the 3-D Deformation Measurement

Wu, Jia-sheng 16 July 2009 (has links)
In this study, a simple and inexpensive membrane mechanical property measuring system was developed. By applying the force on a membrane and recording the corresponding out-of-plane displacement fields, then the Young¡¦s modules and Possion¡¦s ratio of the membrane can be obtained from those deformations through the inverse approach. Firstly, a loading frame was designed to fix the membrane and allow the membrane can be loaded and its deformations can be measured precisely. In order to measure the out-of-plane displacement fields of the loaded membrane, the digital image correlation (DIC) was used and an easier 3-D DIC measuring method was proposed in this study. The proposed 3-D DIC measuring method was verified by using a loaded cantilever beam with ESPI. The error was within in 10%. In this study, the smallest in-plane displacement that can be measured by proposed method is 2 £gm and the smallest out-of-plane displacement that that can be measured is 6£gm. In this study, in order to determine the mechanical properties of the membrane, digital image correlation, finite element method (FEM) and optimization method were combined with the measured out-of-plane displacement fields, then the Young¡¦s modules and Possion¡¦s ratio of the membrane were determined through the inverse approach. The FEM simulations were performed by using ANSYS. Several optimization theorems were adopted and their corresponding merits on this study were compared The obtained Young's modulus was compared with the results obtain from the nano-indentor and the error was within in 3% ~ 12%. Keyword: digital image correlation, membrane, Young¡¦s modules, Possion¡¦s ratio, finite element method, optimization method.

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