Estimation of interlaminar shear strength of CF/PEKK composites by full‐field data‐based numerical simulations of short beam shear tests

Abstract A hybrid methodology is proposed to estimate the Interlaminar Shear Strength (ILSS) of Carbon Fiber and Polyetherketoneketone (CF/PEKK) composites from Short Beam Shear (SBS) tests. Digital Image Correlation (DIC) is used to capture the apparent shear behavior during loading as well as to detect the first sign of diffuse damage, characteristic of thermoplastic behavior. Simulations based on Finite Element Method (FEM) considering the orthotropic ply behavior allowed us to estimate the shear stress fields and finally, to identify the ILSS using a DIC‐based criterion. The methodology is applied to two types of manufactured laminates prepared with a non‐optimal and an optimal manufacturing cycle, to assess the impact of consolidation on macroscopic shear behavior. The estimated ILSS values (62.3 and 70.2 MPa for each manufacturing cycle, respectively) are compared with those obtained from the standard ASTM D2344 (88.1 and 95.7 MPa, respectively) whose limitations are discussed, particularly the out‐of‐plane shear behavior hypothesis. Highlights ILSS obtained via dialog between DIC full‐field data and FEM‐based simulations. Significant differences between SBS strength and ILSS for thermoplastic composites. SBS strength is not representative of ILSS for thermoplastic composites. ILSS is strongly correlated to the composite microstructure at the interply. ILSS is impacted by nonlinear shear behavior.