One-shot Measurement of Thermal and Kinematic Fields: InfraRed Image Correlation (IRIC)

Abstract

Abstract. Many materials are concerned by strain localization, for instance PLC phenomena, Lüders' bands or Shape Memory Alloys (SMA). The experimental identification of such material behaviors requires the use of full field kinematic measurements, such as provided by Digital Image Correlation (DIC), as well as Infra-Red (IR) thermography to evaluate the associate thermal dissipation. Jointly, these field measurements allow for a full thermo-mechanical characterization of material behavior. However, the space and time association of both fields remains a major difficulty (antagonist surface texture requirements, imaging devices having different pixel number and acquisition rate...). In this paper, we introduce a much simpler experimental approach, which consists in a novel extended DIC technique applied to a single set of IR images. It gives access to both displacement and temperature fields decomposed over the same discretization. This technique, applied to tensile tests on a NiTi SMA, reveals both strain localization due to the phase transformation and associated thermal dissipation.

Identification of a crack propagation law by digital image correlation

“…Once the crack tip was determined, the crack growth increment is estimated in addition to other global parameters such as the stress intensity factor range, and T -stress. By analyzing the dominant displacement fields, it can also be concluded that the estimate of the plastic zone size is more difficult and would require analyses with a higher magnification, or even combined kinematic and thermal measurements [39].…”

Regularized InfraRed Image Correlation Applied to Laser-Induced Thermal Shocks

“…Due to a relatively low absorptivity of the polished surface, the incident beam is inclined in order for the reflected beam to be collected by a calorimeter. An infrared camera (x6540sc manufactured by FLIR, definition: 640  512 pixels, λ = 3970-4010 nm) with a high magnification lens is used to measure simultaneously the displacement and temperature fields [12]. The main assumption of DIC is the DL conservation between the registered images.…”

“…The use of IR cameras in the field of experimental mechanics is more and more common [1][2][3][4][5][6][7][8][9][10][11][12][13] in order to quantify the thermomechanical response of materials under load. Most of the time the sought information consists of the kinematic and temperature fields.…”

“…Most of the time the sought information consists of the kinematic and temperature fields. Both are induced by either the mechanical loading [1][2][3][4][5][6][7][8][9][11][12] or the applied thermal history [10,[13][14]. In the first case, temperature elevations are of few degrees Celsius, and accessing the thermomechanical response may provide a better understanding of localization and dissipative phenomena [1][2][3][4][5][6][7][8][9][11][12].…”

“…A less constraining method consists in integrating in the DIC formalism (referred to as InfraRed Image Correlation or IRIC) the occurrence of these DL variations and then use the IR frames. The feasibility of such a method was shown for a single IR camera and temperature variations of few degrees [12]. The DIC formalism consists in considering a sort of "brightness" correction decomposed onto a Finite Element (FE) basis.…”