Thermoelastic Stress Analysis and Dissipated Energy Evaluation Using Infrared-Optical Synchronous Measurement

On the infrared thermography image, a false temperature change caused by the relative displacement between moving object and infrared camera is obtained. This paper shows the motion compensation system with the infrared-optical synchronous measurement. Displacement information of the specimen is calculated from the series of visible light image using the digital image correlation method (DIC). The displacement information on the visible image is reflected to the infrared image by the homography transformation. The random white pattern which can’t be detected by the infrared camera was drawn on the measured surface for DIC process. The developed motion compensation system was applied to the thermoelastic stress analysis and dissipated energy measurement. It was confirmed that a false temperature change and edge effect can be removed by using developed motion compensation system.

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Advanced Technique for Thermoelastic Stress Analysis and Dissipation Energy Evaluation Via Visible-Infrared Synchronous Measurement

Experimental Mechanics ◽

10.1007/s11340-021-00796-5 ◽

2021 ◽

Author(s):

Y. Uchida ◽

D. Shiozawa ◽

M. Hori ◽

K. Kobayashi ◽

T. Sakagami

Keyword(s):

Stress Analysis ◽

Thermoelastic Stress ◽

Thermoelastic Stress Analysis ◽

Dissipation Energy ◽

Advanced Technique ◽

Energy Evaluation ◽

Synchronous Measurement

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Combined thermoelastic stress analysis and digital image correlation with a single infrared camera

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324711418286 ◽

2011 ◽

Vol 46 (8) ◽

pp. 783-793 ◽

Cited By ~ 16

Author(s):

M L Silva ◽

G Ravichandran

Keyword(s):

Digital Image Correlation ◽

Stress Analysis ◽

Digital Image ◽

Thermoelastic Stress ◽

Infrared Camera ◽

Image Correlation ◽

Measured Temperature ◽

Thermoelastic Stress Analysis ◽

Alloy Plate ◽

Full Field

A novel methodology simultaneously combining thermoelastic stress analysis (TSA) and digital image correlation (DIC) with a single infrared camera is presented. DIC is an optical method to determine deformation by image tracking with strains determined via differentiation. TSA is a non-contact measurement technique that provides the full-field stress directly using measured temperature changes. The combination of the two techniques improves the resolution and accuracy of TSA results by correcting for sample motion and distortion during loading. Illustrative examples, including an aluminium alloy plate with an edge crack and a nylon plate with a hole under tension, demonstrate the combined method which simultaneously measures stress and displacement.

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Optical-flow-based motion compensation algorithm in thermoelastic stress analysis using single-infrared video

ACTA IMEKO ◽

10.21014/acta_imeko.v10i4.1147 ◽

2021 ◽

Vol 10 (4) ◽

pp. 169

Author(s):

Tommaso Tocci ◽

Lorenzo Capponi ◽

Roberto Marsili ◽

Gianluca Rossi

Keyword(s):

Optical Flow ◽

Stress Analysis ◽

Displacement Field ◽

Motion Compensation ◽

Thermoelastic Stress ◽

Specimen Preparation ◽

Thermoelastic Stress Analysis ◽

Single Measurement ◽

Infrared Video

<p>Thermoelastic stress analysis (TSA) is a non-contact measurement technique for stress distribution evaluation. A common issue related to this technique is the rigid-displacement of the specimen during the test phase, that can compromise the reliability of the measurement. For this purpose, several motion compensation techniques have been implemented over the years, but none of them is provided through a single measurement and a single sample surface conditioning. Due to this, a motion compensation technique based on Optical-Flow has been implemented, which greatly increases the strength and the effectiveness of the methodology through a single measurement and single specimen preparation. The proposed approach is based on measuring the displacement field of the specimen directly from the thermal video, through optical flow. This displacement field is then used to compensate for the specimen’s displacement on the infrared video, which will then be used for thermoelastic stress analysis. Firstly, the algorithm was validated by a comparison with synthetic videos, created ad hoc, and the quality of the motion compensation approach was evaluated on video acquired in the visible range. The research moved into infrared acquisitions, where the application of TSA gave reliable and accurate results. Finally, the quality of the stress map obtained was verified by comparison with a numerical model.</p>

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