Mechanical stress measurement by an achromatic optical digital speckle pattern interferometry strain sensor with radial in-plane sensitivity: experimental comparison with electrical strain gauges
This paper shows the optical setup of a radial in-plane digital speckle pattern interferometer which uses an axis-symmetrical diffractive optical element (DOE) to obtain double illumination. The application of the DOE gives in-plane sensitivity which only depends on the grating period of the DOE instead of the wavelength of the laser used as illumination source. A compact optical layout was built in order to have a portable optical strain sensor with a circular measurement area of about 5 mm in diameter. In order to compare its performance with electrical strain sensors (strain gauges), mechanical loading was generated by a four-point bending device and simultaneously monitored by the optical strain sensor and by two-element strain gauge rosettes. Several mechanical stress levels were measured showing a good agreement between both sensors. Results showed that the optical sensor could measure applied mechanical strains with a mean uncertainty of about 5% and 4% for the maximum and minimum principal strains, respectively.
- OSTI ID:
- 22036586
- Journal Information:
- Applied Optics, Vol. 50, Issue 7; Other Information: (c) 2011 Optical Society of America; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6935
- Country of Publication:
- United States
- Language:
- English
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