Heat haze effects in thermal chamber tensile tests on digital image correlation

This paper presents simulation data obtained using CFD in ANSYS Fluent for thermal chambers which host tensile test experiments that yield stress-strain relationships through a combination of strain gauges and digital image correlation. These tests are performed from room temperature up to 150°C with comparable simulations in CFD to help understand the results. Problems attributed to heat haze were identified with corrective measures being explored and later implemented. In this paper thermal chamber results from experiments at various temperatures are presented where the effects of optical distortion are demonstrated. At 60°C the optical distortion starts to become significant and dominant at yet higher temperatures, to the extent that corrective measures are essential. Hence the importance of adequate insulation is highlighted and, where not possible, the judicious use of fans is demonstrated to be an acceptable technique for controlling heat haze.