Dynamic Thermo-mechanical Response of Hastelloy X to Shock Wave Loading

Visual Methods to Assess Strain Fields in Armour Materials Subjected to Dynamic Deformation—A Review

“…Two of the cameras were used to conduct 3D DIC and a third perpendicular to the side surface of the specimens to capture the side-view deformation images. The authors show that once a material exceeds a certain temperature, self-radiation of the heated material leads to decorrelation effects in the images, as reported by Pan et al [49] This is due to the radiated light from the heated material dramatically intensifying the brightness, while decreasing the contrast of the captured image [48]. By using an optical band pass filter and a spatial-domain cross-correlation algorithm developed by Pan et al [50], Abotula et al were able to obtain images up to 1200 • C [48].…”

“…The authors show that once a material exceeds a certain temperature, self-radiation of the heated material leads to decorrelation effects in the images, as reported by Pan et al [49] This is due to the radiated light from the heated material dramatically intensifying the brightness, while decreasing the contrast of the captured image [48]. By using an optical band pass filter and a spatial-domain cross-correlation algorithm developed by Pan et al [50], Abotula et al were able to obtain images up to 1200 • C [48]. To maintain the speckle pattern, the authors used a commercially available flame proof paint that is able to sustain temperatures up to 1200 • C. The authors show that the maximum impulse imparted to the specimen increases by approximately 41% between 25 • C and 900 • C. In addition, the maximum deflection also increased with temperature (5.2 mm at 25 • C compared to 13.5 mm at 900 • C), but occurs at a later time.…”

“…Abotula et al were able to divide the structural response into two stages: the first stage where the effects of the boundary conditions are not dominant, and a second stage where the plate is brought to rest by plastic bending and stretching. As the temperature increases and the maximum deflection increases, the maximum in-plane strain values also increase [48].…”

“…Abotula et al [48] conducted a study to investigate the performance of Hastelloy X under a combination of extreme mechanical and thermal environments. This was accomplished by loading the plates with a shockwave, while heating them to high temperatures.…”

High Temperature Vibratory Response of Hastelloy-X: Stereo-DIC Measurements and Image Decomposition Analysis

“…Abotula et al used a pair of high-speed cameras to capture the deformation of Hastelloy (a nickel-based superalloy) samples at temperatures up to 900°C under shock wave loading [8]. To illuminate their specimens, Abotula et al [8] used a 450 nm filter with a full width at half maximum (FWHM) of 40 nm and a transmission efficiency of 45 %, which significantly reduced the amount of light reaching the camera sensors -potentially a critical drawback in high-speed imaging applications which require limited image exposure times. To overcome this limit, they used a high energy flash lamp which delivered 220 kW to the specimen for 5 ms.…”