This work was supported by JSPS KAKENHI, grant numbers JP16K17988 and JP16K05996, and by the Cross-Ministerial Strategic Innovation Promotion Program, Unit D66, Innovative Measurement and Analysis for Structural Materials (SIP-IMASM), operated by the cabinet office. The authors are also grateful to Drs. Satoshi Kishimoto and Kimiyoshi Naito at NIMS for their CFRP material.

1. Confirmation of the Micro/Nano-scale Grid on the Specimen
<ol>
	<li>Machining of the Specimen
	<ol>
		<li>Cut the specimen to the size required by the specific loading device used under a microscope (e.g., 1 x 5 x 30 mm3), making the surface to be observed 1.5x greater than the region of interest.</li>
		<li>Polish the specimen surface to be observed (e.g., 1 x 30 mm2), successively using coarse and fine sand paper on an automatic polishing machine (e.g., ...

<ol>
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In the described technique, one challenging step is the micro/nano-scale grid or grating (abbreviated as grid) fabrication26 if no periodic pattern exists on the specimen. The grid pitch should be uniform before deformation because it is an important parameter for the deformation measurement. If the material is a metal, a metal alloy, or a ceramic, UV or heating nanoimprint lithography (NIL)27, electron beam lithography (EBL)2, focused ion beam (FIB)...

Micro/nano-scale deformation measurements are vitally essential for evaluating the mechanical properties, instability behaviors, residual stresses, and crack occurrences of advanced materials. Since optical techniques are non-contact, full-field, and non-destructive, various optical methods have been developed for deformation measurement during the last few decades. In recent years, the micro/nano-scale deformation measurement techniques mainly include the moir&#233; methods1,2,3,4, geometric phase analysis (GPA)5,6, Fourier transformation (FT), digital image correlation (DIC), and electronic speckle pattern interferometry (ESPI). Among these techniques, GPA and FT are not well suited for complex deformation measurements because multiple frequencies exist. The DIC method is simple but powerless against noise because the deformation carrier is random speckle. Finally, ESPI is strongly sensitive to vibration.
Among micro/nano-scale moir&#233; methods, the most commonly used methods at present are the microscope scanning moir&#233; methods, such as electron scanning moir&#233;7,8,9, laser scanning moir&#233;10,11, and atomic force microscope (AFM) moir&#233;12, and some microscope-based moir&#233; methods, such as the digital/overlapping moir&#233;13,14,15 method and the multiplication/fractional moir&#233; method16,17. The scanning moir&#233; method has many advantages, such as a wide field of view, high resolution, and insensitivity to random noise. However, the traditional scanning moir&#233; method is inconvenient for 2D strain measurements because it is necessary to rotate the sample stage or the scanning direction by 90&#176; and to scan twice to generate moir&#233; fringes in two directions18. Rotation and the dual scanning processes introduce rotation error and take a long time, seriously influencing the measurement accuracy of the 2D strain, especially for the shear strain. Although the temporal phase-shifting technique19,20 can improve the deformation measurement accuracy, it requires time and a special phase-shift device unsuitable for dynamic tests.
The sampling moir&#233; method21,22 has a high accuracy in displacement measurements and is now mainly used for deflection measurements on bridges when automobiles pass. To extend the sampling moir&#233; method to micro/nano-scale 2D strain measurements, a reconstructed multiplication moir&#233; method has been newly developed23 from 2-pixel sampling moir&#233; fringes, in which the measurements are twice as sensitive and the wide field of view of the scanning moir&#233; method is kept. Moreover, the spatial phase-shifting sampling moir&#233; method is also developed from multi-pixel sampling moir&#233; fringes, allowing for high-accuracy strain measurements. This protocol will introduce the detailed strain measurement procedure and is expected to help researchers and engineers learn how to measure deformation, improving the manufacturing processes of materials and products.

<table border="0" cellpadding="0" cellspacing="0" width="737">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Automatic Polishing Machine</td>
			<td style="width:161px;">Marumoto Struers K.K.</td>
			<td style="width:201px;">LaboPol-30, Labor Force-100</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:208px;">Carbon Fiber Reinforced Plastic</td>
			<td style="width:161px;">Mitsubishi Plastics, Inc.&#160;</td>
			<td style="width:201px;">HYEJ16M95DHX1</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:208px;">Computer</td>
			<td style="width:161px;">DELL Japan</td>
			<td style="width:201px;">VOSTRO</td>
			<td style="width:167px;">Can be replaced with another computer with C++ programming language</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:208px;">Image Recording Software</td>
			<td style="width:161px;">Lasertec Corporation</td>
			<td style="width:201px;">LMEYE7</td>
			<td style="width:167px;">Installed in a laser scanning microscope</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Ion Coater</td>
			<td style="width:161px;">Japan Electron Optics Laboratory Ltd.</td>
			<td style="width:201px;">JEC3000F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Laser Scanning Microscope</td>
			<td style="width:161px;">Lasertec Corporation</td>
			<td style="width:201px;">OPTELICS HYBRID</td>
			<td></td>
		</tr>
		<tr height="90">
			<td height="90" style="height:90px;width:208px;">Nanoimprint Device</td>
			<td style="width:161px;">Japan Laser Corporation&#160;</td>
			<td style="width:201px;">EUN-4200</td>
			<td style="width:167px;">Can be replaced with a electron beam lithography device or a focused ion beam milling device</td>
		</tr>
		<tr height="90">
			<td height="90" style="height:90px;width:208px;">Nanoimprint Mold</td>
			<td style="width:161px;">SCIVAX Corporation</td>
			<td style="width:201px;">3.0&#956;m pitch</td>
			<td style="width:167px;">Customized</td>
		</tr>
		<tr height="90">
			<td height="90" style="height:90px;width:208px;">Nanoimprint Resist</td>
			<td style="width:161px;">Toyo Gosei Co., Ltd&#160;</td>
			<td style="width:201px;">PAK01</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Polishing Solution</td>
			<td style="width:161px;">Marumoto Struers K.K.</td>
			<td style="width:201px;">DP-Spray P 15&#956;m, 1&#956;m, 0.25&#956;m</td>
			<td>Use from coarse to fine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Pipet</td>
			<td style="width:161px;">AS ONE Corporation</td>
			<td style="width:201px;">10mL</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Sand Paper</td>
			<td style="width:161px;">Marumoto Struers K.K.</td>
			<td style="width:201px;">SiC Foil #320, #800</td>
			<td>Use from coarse to fine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Spin Coater</td>
			<td>MIKASA Corporation</td>
			<td style="width:201px;">MS-A100</td>
			<td></td>
		</tr>
	</tbody>
</table>

micro/nano-scale strain distribution measurement from sampling moir&#233; fringes

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moir&#233; method or the spatial phase-shifting sampling moir&#233; method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moir&#233; fringes are generated to reconstruct a multiplication moir&#233; pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moir&#233; method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moir&#233; fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moir&#233; techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

The 2D displacement and strain distributions of two carbon fiber-reinforced plastic (CFRP) specimens (#1 and #2) were measured according to the moir&#233; formation principle23 and the measurement process (Figure 1). The CFRP specimens were made up of 10-11 &#181;m-diameter K13D carbon fibers and epoxy resins. The deformation of CFRP #1 was determined using the reconstructed multiplication moir&#233; method from two-step sampling moir&...

Watch this Scientific Journal Video about Micro/Nano-scale Strain Distribution Measurement from Sampling MoirÃ© Fringes at JoVE.com

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&amp;#233; Fringes

A sampling moir&#233; technique featuring 2-pixel and multi-pixel sampling methods for high-accuracy strain distribution measurements at the micro/nano-scale is presented here.

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&#233; Fringes

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. ...

The overall goal of this experiment is to accurately measure the strain distributions of materials at the micro or nano scale using the two-pixel or multi-pixel sampling moir

micronano-scale-strain-distribution-measurement-from-sampling-moire

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Engineering

12.1K visualizações.  National Institute of Advanced Industrial Science and Technology (AIST). The overall goal of this experiment is to accurately measure the strain distributions of materials at the micro or nano scale using the two-pixel or multi-pixel sampling moir