Temperature‐Dominated Deformation Mechanism and Quantitative Prediction of CF / PEKK Prepreg Tape in LAFP Process

ABSTRACT During laser‐assisted automated fiber placement (LAFP) in situ consolidation, width variations in prepreg tapes lead to gaps or overlaps between adjacent tapes, significantly impairing the forming quality of final components. This study investigates the deformation behavior of carbon fiber‐reinforced poly(ether‐ketone‐ketone) (CF/PEKK) prepreg tapes under LAFP. The thermophysical and rheological properties of CF/PEKK are systematically characterized via differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and rotational rheometry. Based on the power‐law fluid constitutive model, a wide‐temperature‐range prediction model for prepreg tape deformation was established by fitting the temperature‐dependent functions of the consistency parameter K and power‐law index n , and multi‐temperature LAFP in situ consolidation experiments were conducted to verify the model. The predicted values agree well with the experimental measurements; within 360°C–440°C, the prepreg tape width increases significantly with rising temperature, with deformation rates of 4.2%–16.6%. Microscopically, optical microscopy reveals that elevated temperature enhances resin fluidity and effectively reduces voids and resin‐rich regions. Meanwhile, a fully coupled quantitative constitutive model correlating the molten apparent viscosity of CF/PEKK with temperature and shear rate is constructed, providing a theoretical basis for the optimization of LAFP process parameters.