Two full-field identification methods are applied to the Wedge Splitting Test (WST) to obtain crack tip positions, stress intensity factors (SIFs) and T -stress.The first method is based on Finite Element Model Updating (FEMU), and the second is integrated digital image correlation (IDIC). Both are applied to a simplified virtual experiment and then to a cyclic WST. The gray level residuals are used to assess which results are more trustworthy. Fracture energy analyses are performed to validate the estimated R-curves.

A cohesive zone approach is applied to the Wedge Splitting Test (WST) using the finite element code Abaqus to obtain the tensile strength, the fracture energy and insight about the crack wake region. A Finite Element Model Updating (FEMU) method, with a cost function based on the measured load (FEMU-F), is used to calibrate the sought parameters. Digital Image Correlation (DIC) provided the kinematic boundary conditions, and the images were also used to define the geometry for the finite element analysis. Besides the fracture energy analysis and the experimental load, gray level images and displacement fields are analyzed in order to validate the results. The cohesive region is active in the whole analyzed test as confirmed by estimates using the cohesive length.

International audienceOne of the key mechanical properties of refractories is their toughness. The latter can be evaluated via wedge splitting tests. One such test is analyzed herein with an integrated approach to digital image correlation. The position of the crack tip, stress intensity factors and T-stress are estimated on two faces of the tested sample made of a refractory castable during the whole cyclic test. It is shown that the change of energy release rate with the crack length can be determined at each time step of the experiment

Refractory castables are utilized in hazardous environments and thus their reliability should be accurately evaluated to avoid incidents. This work aims to measure the fracture energy of a high-alumina refractory with mullite-zirconia aggregates at 600°C. Wedge Splitting Tests were performed on 5 samples with different sintering temperatures. Images were acquired and analyzed via Digital Image Correlation (DIC). Notch Opening Displacements were used to evaluate the fracture energy at room and high tempartures. For the studied material, a 50°C increase in the sintering temperature increased about 30% the fracture energy of the material, which is also higher at 600°C when compared to room temperature measurements.