Original title: Strain Analysis of Metals Under Compression Using Shearing Interferometry and Strain Gauges
Ernesto J. Ruiz-Ortega, Francisco G. Peña-Lecona, Jesús Muñóz-Maciel, Francisco J. Casillas-Rodríguez +2 · September 2026
When external forces squeeze a material, it deforms inside. Engineers usually track this with physical sensors that turn mechanical motion into electrical readouts, but they can also use light to test materials without damaging them. In this study, researchers compressed four metals used in cars and airplanes: 6061 aluminum, plus 304, 1045, and 4041 steels. To see how each metal deformed, they used a shearing interferometer. This optical tool splits and shifts light across the squeezed surface, creating striped light patterns called fringes that reveal surface shifts. They squeezed each sample with forces ranging from 491 N to 2453 N. By processing the light patterns into phase data, they found that each metal showed a different elasticity. Finally, these light-based measurements matched the results from electrical strain gauges placed on the back of the samples and lined up with computer-based finite element analysis.
Imagine pressing a clay brick and trying to see how much it squishes. You could push pins into it and measure how far they move, but that changes the clay. Alternatively, you could shine a flashlight on it and watch how the shadows shift. In this paper, the researchers pressed metal samples and used a laser to create shadow-like patterns that reveal the tiny shape changes. They then compared those patterns with results from pin-like sensors and a computer model, and all agreed.
This work offers a noninvasive way to measure strain in metals used in cars and planes. Instead of attaching sensors that can interfere with the material, engineers can use light to see how parts deform under pressure. This could enable faster or more flexible testing in quality control and design.
The abstract does not specify limitations, but it only tests four metal types and forces up to 2453 N. The method requires optical access to the surface, so it may not work for hidden or curved parts. Comparisons with strain gauges were on the opposite side, so exact local match is not directly checked. No data on measurement uncertainty or repeatability is given.
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Strain Analysis of Metals Under Compression Using Shearing Interferometry and Strain Gauges — Ernesto J. Ruiz-Ortega, Francisco G. Peña-Lecona, Jesús Muñóz-Maciel et al. — Optics — doi:10.3390/opt7050065
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.