The potential use of composite repairs to reinforce crack or crack-like features has become an increasingly frequent discussion point as advancements in inspection technology better detect the presence of these defects. Many manufacturing defects, especially seam weld anomalies, such as lack-of-fusion, are just now being identified after having been in service for decades and don’t necessarily show signs of immediate concern warranting cut-out and replacement. Composite repairs, now backed by several years of testing and field use, are positioned to support these situations and provide safe, cost-effective solutions.
This paper focuses on combining the theory of stress distribution in multilayered systems and a standard fracture mechanics model to conservatively estimate the effect of installing composite repair on crack or crack-like features. This model allows a quick and relatively simple approach for feasibility analysis using very conservative assumptions without having to replicate the scenario through Finite Element Analysis. With estimated material properties and expected cyclic performance, it is possible to identify defects that can be repaired as a low-risk, long-term repair or a short-term temporary repair. Additionally, review of previous test programs will be performed showing the conservative nature of this model and identifying potential future research topics that would allow for more accurate modeling.