title: Polarized digital shearography for simultaneous dual shearing directions measurements.
abstract: The selection of the direction of sensitivity for digital shearography is determined by its shearing direction. As a result, directionally shaped defects could be missed in non-destructive testing using a digital shearography system with only one shearing direction. This paper reports a polarized digital shearography system based on two Mach-Zehnder interferometers, which can create two orthogonal shearing directions and record shearograms in the two orthogonal directions simultaneously. The two shearograms are separated from each other by proper polarization design so that no cross interference occurs. The phase maps of the shearograms are generated by spatial phase shift methods through the introduction of different carrier frequencies in the two orthogonal shearograms and use of the Fourier transform method. This enabled simultaneous dual directional non-destructive testing during continuous loading. Theory derivation, spectrum analysis, and non-destructive testing application results are shown in detail.
authors: Optical Laboratory, Department of Mechanical Engineering, Oakland University, 2200 N. Squirrel Rd., Rochester, Michigan 48309, USA.
authors: Xin
authors: X
authors: Xie
authors: Ngee Ann Polytechnic, 535 Clementi Road, Singapore 599489, Singapore.
authors: Cheok Peng
authors: CP
authors: Lee
authors: Optical Laboratory, Department of Mechanical Engineering, Oakland University, 2200 N. Squirrel Rd., Rochester, Michigan 48309, USA.
authors: Junrui
authors: J
authors: Li
authors: Optical Laboratory, Department of Mechanical Engineering, Oakland University, 2200 N. Squirrel Rd., Rochester, Michigan 48309, USA.
authors: Boyang
authors: B
authors: Zhang
authors: Optical Laboratory, Department of Mechanical Engineering, Oakland University, 2200 N. Squirrel Rd., Rochester, Michigan 48309, USA.
authors: Lianxiang
authors: L
authors: Yang