Book ChapterDOI
Accurate Strain Distribution Measurement Based on the Sampling Moiré Method
Shien Ri,Y. Fukami,Y. Fukami,Qinghua Wang,Shinji Ogihara +4 more
- pp 243-249
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TLDR
In this article, the sampling moire method is applied to two-dimensional measurement of in-plane displacement and strain distributions, and a compensation technique of fringe order is proposed to eliminate the pitch error of fabricated grating, while a spatial filtering procedure in phase distribution is suggested to reduce the random measurement error.Abstract:
To obtain accurate measurement of non-uniform strains over the entire surface of materials or structures, in this study, the sampling moire method is applied to two-dimensional measurement of in-plane displacement and strain distributions. The two-dimensional displacement distribution is obtained by detecting the phase difference of the moire fringes, and the strain distribution is determined by measuring the change of grating pitches on the specimen in vertical and horizontal directions before and after deformations. A compensation technique of fringe order is proposed to eliminate the pitch error of fabricated grating. In addition, a spatial filtering procedure in phase distribution is suggested to reduce the random measurement error. The deformations of an aluminum specimen with a through hole under different tensile loads were measured by the proposed method. Experimental results indicated that the measurement accuracy of strain distribution can be dramatically improved by combination the above-mentioned two techniques. This method is useful to evaluate mechanical properties of various materials under tension/compression or heating/cooling testing.read more
Citations
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Journal ArticleDOI
Optical full-field strain measurement method from wrapped sampling Moiré phase to minimize the influence of defects and its applications
TL;DR: In this article, a simple local phase unwrapping algorithm was proposed to minimize the influence of defects on full-field strain measurement, where the Moire phases are first acquired by the sampling Moire technique, and the wrapped Moire phase difference is then calculated to determine the strain distributions by only unwrap the phase difference at the boundaries of the wrapped phase.
Journal ArticleDOI
Sampling Moiré method using non-sinusoidal grating
TL;DR: The proposed formulation removes the phase errors that are due to non-sinusoidal functions in any phase measurement systems that use phase-shifting techniques by taking in to account other harmonics of the grating function.
Journal ArticleDOI
Fabrication of heat-resistant grids and their application to deformation measurements using a sampling moiré method
Yangyang Li,Qi Zhang,Huimin Xie +2 more
TL;DR: In this paper, an etched-paint-film grid-fabrication technique using a laser-marking technique is proposed to satisfy the fabrication demand for heat-resistant grids for the sampling moiré method.
Journal ArticleDOI
Sampling moiré method: A more exact solution
TL;DR: In this paper , the phase measurement of a grating image by using the phase of the moiré fringe from a single-shot image has been studied and it is shown that the exact magnitude of the phase shift is 2π/T, where T is the period of the grating.
References
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Journal ArticleDOI
Application of an optimized digital correlation method to planar deformation analysis
TL;DR: The optimized digital correlation method has been developed to improve previously reported iterative DCMs and is shown to be much faster than previous methods while achieving accuracy equivalent to that obtained via simple coarse-fine iterative techniques.
Journal ArticleDOI
A simple and effective method for filtering speckle-interferometric phase fringe patterns
TL;DR: It is shown that a simple process such as multiple repetition of an anisotropic sine/cosine average filter produces the effect of an excellent automatic adaptive filter for filtering speckle-interferometric phase fringe patterns.
Journal ArticleDOI
Sampling Moiré Method for Accurate Small Deformation Distribution Measurement
TL;DR: In this paper, a novel accurate deformation distribution measurement technique by using sampling moire method is proposed, where the measurement area of a target is attached with an adhesive tape of a known pitch grating firstly.
Journal ArticleDOI
Shearography for non-destructive evaluation of composite structures
TL;DR: Shearography is equivalent to a full-field strain gage which allows strain distribution over a large area to be observed, and it does not require installing strain gauges/transducers.
Journal ArticleDOI
Automated fine grid technique for measurement of large-strain deformation maps
TL;DR: In this article, the Fourier transform was used to estimate the in-plane components of strain on a propellant simulant containing burn holes, up to strains of approximately one-third.