Impact damage and bearing capacity of CFRP laminates with pretensioned tooth joints and graded thickness

• CFRP tooth joint capacity rises 160% (17-44 kN) as thickness grows from 10 to 30 mm. • Failure shifts from global crushing to pure shear as laminate thickness increases. • FE model reveals thickness-driven stress homogenization and damage localization. • A novel Failure Mechanism Map is created to guide crashworthy joint design. This study investigates the impact response and bearing capacity of carbon fiber reinforced polymer (CFRP) laminates with pretensioned tooth joints by integrating experimental and numerical approaches. Split Hopkinson pressure bar (SHPB) tests on laminates with graded thickness (10–30 mm) revealed three primary failure modes: shear failure of the teeth, compressive crushing, and interlaminar delamination. Laminate thickness critically influenced the post-impact performance, with bearing capacity increasing progressively from 16.97 kN (10 mm) to 44.23 kN (30 mm). This enhancement was correlated with a distinct transition in damage patterns: severe compound failure (tooth shear & global crushing) at 10 mm, moderate delamination-dominated damage at 20 mm, and localized single-mode shear failure at 30 mm. Scanning Electron Microscopy (SEM) confirmed micro-mechanisms including matrix crushing and fiber-matrix debonding. Furthermore, a comprehensive finite-element model was developed and validated against experimental results. The simulation visualized the stress distribution and damage evolution, confirming that increased thickness promotes stress homogenization and damage localization. Ultimately, a novel Failure Mechanism Map was constructed, synthesizing the experimental and numerical data into a predictive design tool that charts the transition between failure modes as a function of laminate thickness and impact velocity. The findings systematically quantify the thickness-driven performance benefits and provides a foundational framework and a practical design tool for optimizing crashworthy CFRP joint designs in impact-critical applications.