UC San Diego

One of the most common types of damage in composite laminates is delamination. This type of damage occurs when the plies within the material separate, reducing the strength and, if ignored, possibly leading to structural failure. The repair of these materials is costly and limited by tool availability, which motivated the adaptation of a repair technique known as injection repair for strength-restoring applications. The goal of this work is twofold: first, to develop a data processing and visualization computational tool that generates three-dimensional maps and delamination density plots from ultrasonic pulse-echo C-scan data, which would be used to assist in identifying percolation pathways within an damaged composite material; and second, to develop a drilling process that produces favorable hole geometry for resin penetration into delaminations while minimizing drilling-induced damage and debris accumulation. The drilling process incorporates carefully selected drilling tools to achieve the desired geometry, tailored drilling parameters to prevent further damage, and a customized vacuum jig for debris mitigation. In parallel, the computational code uses C-scan data to generate three-dimensional maps of internal damage. Moreover, when both front- and back-side C-scan data are available, the code combines them into a single hybrid three-dimensional reconstruction. This three-dimensional data reconstruction also enables identification of the damage network branches within the composite via delamination density maps. The delamination network branches serve as optimal hole locations for resin injection, while the developed drilling methods help mitigate drilling-induced damage and debris contamination, thereby improving percolation efficiency and contributing to the development of injection repair.