Coupled NIRT/3D-DIC for a FEMU Identification of the Thermo-Mechanical Behavior of Zr-4 Claddings Under Simulated Reactivity Initiated Accident

Abstract

Nowadays, full field measurements techniques enable heterogeneous experiments to be performed without the need of averaging assumptions. The richness and the quantity of recording data obtained by these techniques led to the development of robust identification methods, such as the finite element model updating (FEMU) technique. However, it is still difficult to measure both kinematic and thermal full fields at the same location and time since the methods and the devices used to compute them are radically different. Furthermore, it may be complicated to calibrate the temperature measurement system without interfering with the metallurgical state of the sample. The present paper proposes a low-cost procedure that uses the same two CMOS cameras to compute both the 3D-surface kinematic field and the associated thermal field, by stereo-correlation and near infrared thermography, respectively. No interpolation or smoothing operation were finally necessary.

Thermo-mechanical behavior of Zircaloy-4 claddings under simulated post-DNB conditions

“…The accuracy on the temperature was estimated around 0.7% of the measured temperature [23]. More details on the procedure followed can be found in [30].…”

FEMU based identification of the creep behavior of Zircaloy-4 claddings under simulated RIA thermo-mechanical conditions

“…The thermal and the kinematics fullfields were measured by near infrared (NIR) thermography and stereo-correlation (3D-DIC), respectively. A methodology, presented in [16], enabled the two kinds of fields to be obtained using the same two CMOS cameras. Thus, the displacement 115 evolution, as well as the temperature evolution, were obtained on the whole region seen by the cameras.…”

“…where Ur is the radial displacement rate, and R e is the external radius of the sample. The set of parameters λ 0 is then identified using the Equations (1), (10), (15) and (16). All the radial displacement values 395 obtained in the tests are used to perform the initialization.…”