Increasing Allowable Flight Loads by Improved Structural Modeling

The tradeoffs of allowable flight loads and safety of aerospace structures via deterministic and probabilistic design methodologies are analyzed. The methodologies are illustrated by performing allowable flight load calculation of a sandwich panel used in aerospace structures. The effect of using a more accurate prediction technique for interfacial fracture toughness that combines interfacial fracture toughness with mode mixity instead of using the traditional model that disregards mode mixity is explored. It was found that by utilizing this more accurate model with the change in B-basis properties, the deterministic approach allows a 13.1% increase in the allowable flight load and a reduction of probability of failure by a factor of five. The probabilistic approach allows a 26.5% increase in allowable flight load, while maintaining the original probability of failure.