Development of Robust Method for Deformation Measurement Using Hybrid Hexagonal Pattern

• Main Authors: VU, THANH-NAM, 武成南
• Other Authors: CHIANG, PEI-JU
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/sdhmex

碩士 === 國立中正大學 === 機械工程系研究所 === 106 === In this thesis, a new robust grid-based method using the hybrid hexagonal pattern to measure the in-plane displacement and strain is proposed. Although digital image correlation (DIC), a non-contact strain measurement method, is a well-developed approach for this particular application, the measurement accuracy strongly depended on the size of random speckle and distribution of grey levels on the sample surface. Typically, inconsistent illumination and large deformation between two deformation states will cause large correlation errors. In contrast, the proposed grid-based method using the hexagonal pattern is relatively robust to the non-uniform illumination and suitable for the case under large deformation. The grid points of the pattern between each state are registered based on corner features. In this study, various types of distortion were applied to both the proposed pattern and DIC pattern with illumination and noise inference. The measurement errors of them are measured and compared. The experimental results show that when the specimen suffers severe deformations, the proposed method performances better than DIC. Keywords: displacement measurement, grid-based, hexagonal pattern, M-array