Multi-level repair decision-making process for composite structures

This paper details the development of a decision-making model that evaluates the multiple repair levels that a composite structure can undergo, each with its inherent achievable survivability and consequence to operations in terms of availability, costs, and scheduling. The goal of this model is to provide the maintainer an integrated approach to all feasible repair solutions within the operational and structural integrity constraints, applicable to any given damage levels found during monitoring. At its core, the model incorporates various stochastic processes to model different types of repairable behavior: the non-homogeneous Poisson process and the renewal process. A case study on the carbon-fiber reinforced polymer flaps of a Boeing 777 has been performed to verify and validate the proposed decision-making model. With the case study providing the means for application of the model in an operational context, a standardized decision making process was delivered that is adaptable to any given failure scenario and implementable in practice.