A Probabilistic Approach For Design And Certification Of Self-Healing Advanced Composite Structures

Design and certification of novel self-healing aerospace structures was explored by reviewing the suitability of conventional deterministic certification approaches. A sandwich structure with a vascular network self-healing system was used as a case study. A novel probabilistic approach using a Monte Carlo method to generate an overall probability of structural failure yields notable new insights into design of self-healing systems, including a drive for a faster healing time of less than 2 hours. In the case study considered, a mature self-healing system could be expected to reduce the probability of structural failure (compared to a conventional damage tolerant construction) by almost an order of magnitude. In a risk-based framework this could be traded against simplified maintenance activity (to save cost) and/or increased allowable stress (to allow a lighter structure). The first estimate of the increase in design allowable stresses permitted by a self-healing system is around 8%, with a selfhealing system much lighter than previously envisaged. It is thought these methods and conclusions could have wider application to self-healing and conventional high-performance composite structures.