Uncertainty quantifiation with mitigation actions for aircraft conceptual design

Abstract

There are always differences between conceptual design estimates and the performance of a final product. These differences may result in constraint violations, which can have severe financial impacts. Such violations may necessitate downstream changes to recover aircraft performance. The ability to estimate the likelihood and impact of late-stage changes is key to mitigating the overall risk of a design.

Reliability methods can treat design uncertainty; however, existing methods do not account for aspects of aircraft design such as sizing processes, the design freeze after conceptual design, and late-stage ``mitigation actions'' taken when a performance constraint is violated. By accounting for these elements, new reliability metrics can be developed. In addition to the probability of compliance, the designer can determine the probability of recovery through mitigation actions, which helps determine the true likelihood that a design can meet the requirements.

Hypotheses are developed to fill the identified gaps, resulting in Aircraft Recovery through Mitigation & Optimization under Uncertainty for Reliability. ARMOUR augments reliability methods by integrating aircraft sizing, uncertainty margins, and mitigation actions. ARMOUR is demonstrated on the conceptual design of a large civil transport and is exercised to explore previously obscured relationships.

The field of probabilistic aircraft design is enhanced by the concurrent quantification of three elements in one design environment: probability of compliance, probability of recovery after failure, and traditional design criteria. ARMOUR enables the identification of designs which both meets reliability goals and optimizes a traditional performance metric, selecting a design that efficiently meets reliability requirements.