Identification of the effective interface between the homogenized phases of a dual-weave 3D composite

Hybridization enhances composite properties by assembling several reinforcement materials. In woven composites, the distribution of different yarns can induce a macroscopic heterogeneity in the thermomechanical properties, which can be considered in the modeling through the introduction of homogenized phases regionally. Identifying the interfaces between those effective phases based on the geometry is difficult due to the yarn entanglement at the interfaces. This work proposes to identify the optimal positions of interfaces by observing the global mechanical behavior of the composite. An asymmetric glass/carbon-hybrid 3D-interlock fabric is studied. It results in a dual-weave composite modeled as macroscopically bi-phased material. It is shown that the effective interface position can be determined from a heating-cooling experiment tomographied in-situ, and processed by Integrated Digital Volume Correlation (IDVC), together with some of the thermomechanical properties of each phase. To enhance IDVC sensitivity, a specific procedure is designed to include the specimen boundary in the analysis.