Application of digital image analysis to strain measurement at elevated temperature

Turner, John E.; Russell, Samuel S.

doi:10.1111/j.1475-1305.1990.tb00026.x

Cited by 23 publications

(8 citation statements)

References 2 publications

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“…Despite prior efforts, [10][11][12][13] obtaining and imaging effective speckle patterns for high-temperature studies still remains a challenge. One challenge at higher temperatures is that the intensity of thermal radiation from the specimen can overwhelm the camera sensor, thus making it unable to capture the speckle pattern on the specimen surface.…”

Section: Challenges With High-temperature Dic Measurementsmentioning

confidence: 99%

Digital image correlation study of mechanical response of nickel superalloy Hastelloy X under thermal and mechanical cycling: Uniaxial and biaxial stress states

Swaminathan

Lambros

Şehitoğlu

2013

The Journal of Strain Analysis for Engineering Design

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The cyclic plastic strain accumulation of a dynamic strain aging Ni-based superalloy, Hastelloy X, is investigated using digital image correlation under both uniaxial and biaxial thermomechanical loading conditions. Thermal cycling and uniaxial mechanical tensile loading demonstrate that this material exhibits a Cottrell-Stokes-type response in which yield stress is not fully recovered after a mechanical loading cycle followed by a second isothermal loading cycle at elevated temperature (between room temperature and 600°C in this work). The Portevin-Le Chatelier dynamic strain aging effect at higher temperatures, which has been seen to occur in this material, may also contribute to this reduction in flow stress. Additionally, under biaxial stress states introduced by means of a double-notch experimental sample, various cyclic thermal and mechanical loading combinations demonstrated a complex thermomechanical plastic response of this material. For example, cyclic thermal loading experiments at fixed displacement amounts for each cycle show greater plastic strain accumulation after three cycles when cycling is performed at a combination of 300°C and 600°C than that for three isothermal 600°C cycles.

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Section: Challenges With High-temperature Dic Measurementsmentioning

confidence: 99%

Digital image correlation study of mechanical response of nickel superalloy Hastelloy X under thermal and mechanical cycling: Uniaxial and biaxial stress states

Swaminathan

Lambros

Şehitoğlu

2013

The Journal of Strain Analysis for Engineering Design

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“…As an image-based deformation measuring technique, DIC relies on digital image processing and numerical computation. Through the continuous efforts on the key technical issues in hightemperature deformation measurement, DIC techniques have been increasingly applied for high-temperature deformation measurement of various materials and structures [8][9][10]. For example, by suppressing the thermal radiation from the heated sample and heating elements using active imaging technique (i.e., bandpass filter imaging and monochromatic lighting) [11], the applicable temperature range of high-temperature DIC methods has been extended to 2000 • C or even 3000 • C [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Ultra-Stable and Customized High-Temperature Speckle Patterns Using Air Plasma Spraying and Flexible Speckle Templates

Lu,

Yu,

Wang

et al. 2023

Sensors

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Reliable and accurate full-field deformation measurements at elevated temperatures using digital image correlation (DIC) require stable and high-contrast high-temperature speckle patterns to be prepared on the sample surface. However, conventional high-temperature speckle patterns fabricated by the existing methods possess several limitations, e.g., easily fail to preserve original pattern features due to the harsh environment and heavily dependent on the operator’s experience. In this study, we propose a reliable and reproducible high-temperature speckle fabrication method based on air plasma spraying (APS) and flexible speckle templates. This method involves covering the sample surface with pre-designed speckle templates and then spraying the melted speckle powders onto the specimen surface using an air plasma spray technique to obtain customized speckle patterns. The validity of the proposed method was verified by the speckle fabrication on both planar and curved samples and heating tests with these samples. Experimental results demonstrate that the speckle patterns made by the proposed method adhere well to the sample surface, remain stable during the heating process, and exhibit excellent agreement with the reference values in terms of the thermal expansion coefficients. The proposed method provides a reliable and efficient way to create customized and stable speckle patterns for accurate high-temperature DIC measurements.

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“…The search for a ‘good’ speckle pattern still presents challenges, and many studies are still being conducted into speckle creation at high temperatures. For example, Turner et al, [ 7 ] Lyons et al, [ 8 ] Pan et al, [ 9 ] Hammer et al [ 10 ] and Chartrel et al [ 11 ] used high‐temperature paint to create speckles. Speckles made by airbrush or spraying techniques have various sizes, from 10 μm to 1 mm, with an image resolution of 20–50 μm/pixel.…”

Section: Introductionmentioning

confidence: 99%

Speckle pattern creation methods for two‐dimensional digital image correlation strain measurements applied to mechanical tensile tests up to 700°C

Luong

Bonnaire

Périé

et al. 2021

Strain

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The purpose of this study is to develop novel speckle pattern techniques for digital image correlation (DIC) kinematic measurements of mechanical tests at high temperatures, typically from 400 to 700°C. In this context, the speckle pattern should not only meet morphological criteria (size, density, distance) in order to improve spatial resolution, but it should also present a high contrast and resist high temperature and strain levels. To find a speckle pattern matching these specifications, a comparison was performed on six types of speckle made using different techniques. First, a computer‐generated speckle pattern that meets DIC criteria was numerically designed to produce six types of speckle pattern. Next, the speckle patterns produced using these six techniques were compared in terms of speckle morphology, image quality and adherence to titanium alloy TA6V material at high temperatures. From 25 to 600°C, the speckle pattern made by the technique combining anodisation and laser engraving named M5 technique gave the best contrast (highest value of mean intensity gradient [MIG] and Shannon entropy value) and the adherence of 200% of strain measurements to the TA6V material. At 700°C, speckle image quality is considerably reduced due to oxidation of the titanium alloy, and this may not be suitable for DIC measurements. Only the speckles produced by painting in which the paint plays a protective role provide with a better speckle contrast compared with other techniques. However, these speckle patterns enable only a strain measurement of 22% by the DIC method. This article concludes with guidelines for producing a speckle pattern suitable for high‐temperature mechanical tests.

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Application of digital image analysis to strain measurement at elevated temperature

Cited by 23 publications

References 2 publications

Digital image correlation study of mechanical response of nickel superalloy Hastelloy X under thermal and mechanical cycling: Uniaxial and biaxial stress states

Digital image correlation study of mechanical response of nickel superalloy Hastelloy X under thermal and mechanical cycling: Uniaxial and biaxial stress states

Fabrication of Ultra-Stable and Customized High-Temperature Speckle Patterns Using Air Plasma Spraying and Flexible Speckle Templates

Speckle pattern creation methods for two‐dimensional digital image correlation strain measurements applied to mechanical tensile tests up to 700°C

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