Fourier transform moiré strain analysis by using cross gratings produced from iron-on paper and inkjet printer

Abstract

Due to the advance in digital image acquisition systems, optical methods for measurement have become more and more popular. The Moire effect is a well-known method which can be used to measure in-plane and out-of-plane deformations. Fourier transform moire method and grid method (FTMGM) is an excellent method for full-field, large in-plane deformation measurement, and can be implemented for the in-plane strain measurement of polymeric materials. An easy and inexpensive method to prepare gratings on specimens for FTMGM is presented. In order to demonstrate this method, a cross grating was generated and was put onto a notched photoelastic plastic sheet. The subsequent fringe and strain analysis was carried out by a toolbox developed by the authors under the MATLAB environment.