Effect of Strain Rate and Loading Conditions on the Mechanical Behavior of <scp>CF</scp> / <scp>PEEK</scp>

ABSTRACT This study systematically investigates the influence of strain rate and loading conditions on the mechanical behavior of continuous carbon fiber‐reinforced polyether ether ketone (CF/PEEK) thermoplastic composites. Quasi‐static (0.001 s −1 ) and dynamic compression tests (1000–3000 s −1 ) were conducted on specimens with two laminate orientations ([0/90] and [+45/−45]) under both in‐plane and out‐of‐plane loading. Results reveal a pronounced strain rate sensitivity, particularly in the transition from quasi‐static to dynamic loading, which shifted failure modes from single‐stage brittle fracture to progressive, localized damage. The compressive modulus generally increased with strain rate across all conditions. Laminate orientation played a critical role: [+45/−45] laminates exhibited superior energy absorption and higher damage thresholds under out‐of‐plane compression at low to medium rates, while [0/90] laminates showed severe delamination under in‐plane loading. Out‐of‐plane compressive strength significantly exceeded in‐plane strength for both orientations, highlighting the material's anisotropy. The [+45/−45] configuration under in‐plane loading demonstrated marked elastoplasticity and efficient energy dissipation via matrix yielding and fiber reorientation. These findings provide essential insights into the dynamic performance and failure mechanisms of CF/PEEK, supporting its application in impact‐resistant aerospace structures.