Infrared‐Nanosecond Laser Stepped‐Scarf Repair: Accuracy and Mechanical Performance of Aircraft Composites Structures

ABSTRACT Repairing damaged carbon fiber‐reinforced polymer (CFRP) structures in aircraft requires precise material removal from the affected region to conform to the repair design. The geometric accuracy of the processed area directly influences the structural integrity and functional restoration of the repaired component. This study compares laser processing with conventional pneumatic grinding, assessing machining accuracy (shape, dimensions, and depth) and surface characteristics on stepped CFRP configurations. The influence of configuration accuracy on the mechanical properties of repaired CFRP laminates was systematically investigated. Results show that laser processing achieves shape and dimensional accuracies of up to 99.9% and 99.0%, respectively, with depth precision controllable within ±10 μm. Moreover, the carbon fiber surface within the processed region retains its original plain‐weave architecture, which increases surface roughness, improves interface wettability, and promotes better bonding. Building on previous work, a comprehensive mechanical performance evaluation—including bending, impact, and compression‐after‐impact (CAI) tests—was conducted for CFRP repaired by both laser processing and pneumatic grinding. The findings reveal that enhanced structural stiffness mitigates dent depth and damage severity while improving impact and CAI resistance. Ultrasonic C‐scan results further confirm the superiority of laser processing in suppressing inelastic damage and localized failure. Owing to its high precision, controllability, and repeatability, laser‐based configuration technology demonstrates strong potential as an eco‐friendly repair method for CFRP structures in aerospace applications.