Open Access

ABSTRACT

The Out-of-Plane Strain Measurement of Composite Sandwich Plate with Fully-Potted Insert Using Digital Phase-Shifting Shearography

by Song-Jeng Huang¹, Yan-Fu Liu²

1 Department of Mechanical Engineering, National Chung Cheng University, Ming-Hsiung, Chia-Yi, 621, TAIWAN
2 Department of Mechanical Engineering, National Chung Cheng University, Ming-Hsiung, Chia-Yi, 621, TAIWAN

The International Conference on Computational & Experimental Engineering and Sciences 2007, 4(3), 187-194. https://doi.org/10.3970/icces.2007.004.187

Abstract

A digital shearographic (DS) technique is a tool well-suited for precision strain measurement and is a nondestructive testing technology. But the fringe patterns of shearography are not so clear. A phase-shifting technique is incorporated into DS and demonstrated to yield fringe patterns with good quality. The major purpose of this study is to produce a measuring system of digital phase-shifting shearography (DPSS) to measure out-of-plan strain of sandwich plate with fully-potted insert. The system mainly includes piezoelectric transducer, servo controller, Michelson shearing mechanism, image processing system and loading system. The Macy algorithm is used for program simulation, and applying noise examined the influence after phase unwrapping. The four-step phase shifting method is used to obtain phase map and then the phase expansion is proceeded by Macy algorithm to obtain the out-of-plane strain (dw/dx) of honeycomb sandwich plate with insert/potting material. Finally, comparing out-of-plane strain of DPSS with DS shows about 2% to 7% difference.

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