Mechanical characterization of composite structures using digital image correlation technique

The use of adhesive joints in many critically important industrial areas necessitates obtaining reliable data in determining their mechanical behavior through experimental, numerical and analytical studies. In the first stage of this study, the mechanical characterization of composite structures produced by combining a structural adhesive (DP810) and an aluminum alloy bonded material (AA2024-T3) was examined through experimental and numerical approaches. In experimental analyses, all deformation measurements were made with two-dimensional digital image correlation technique (DIC); elastic properties of the adhesive, fracture energies in Mode I and Mode II, and model parameters required for the cohesive zone approach were determined using different experimental methods. In addition, in order to determine the reliability of these parameters in numerical analyses, experimental and Cohesive Zone Modeling (CZM) technique approach numerical analyzes were conducted on the behavior of scarf joint samples created using AA2024-T3 aluminum alloy and DP810 adhesive under different load conditions (tensile and three-point bending). In the second stage, in line with the results obtained in the first stage, it was concluded that the experimental parameters were reliable and repeatable, and parametric studies were carried out on the T-bonding connection, which is a connection type widely used especially in aviation applications. In conclusion; it was determined that there is a good agreement between experimental and numerical results, the DIC technique is an important deformation measurement tool in the mechanical characterization of adhesive-bonded composite structures, and since inelastic effects are taken into account in the CZM technique, the mechanical behavior, damage and strength predictions of structural adhesives with high toughness can be accurate and repeatable.