(Georgia Institute of Technology, 2021-01-04)
Bendarkar, Mayank; Sarojini, Darshan; Harrison, Evan D.; Mavris, Dimitri N.
General Aviation (GA) is likely to be at the forefront of a paradigm change in aviation, where the introduction of novel concepts such as Urban Air Mobility (UAM), architectures like e-VTOL, and technologies like Distributed Electric Propulsion (DEP) are expected to make aircraft more efficient and reduce their environmental footprint. However, these architectures carry with them an uncertainty related to the off-nominal operational risk they pose. The limitations and off-nominal operational considerations generally postulated during traditional safety analysis may not be complete or correct for new technologies. While a lot of the literature surveyed focuses on improving traditional methods of safety analysis, it still does not completely address the limitations caused due to insufficient knowledge and experience with transformative technologies. The research objective of the present work is to integrate the Bayesian safety assessment framework developed previously by the authors with conceptual and 6-DoF performance models for DEP aircraft to evaluate off-nominal performance and reliability using information that is typically available in conceptual or preliminary design phases. A case study on the electric power architecture of the the NASA Maxwell X-57 Mod. IV is provided. A maximum potential flight path angle metric, as well as trimmability considerations using a 6-DoF model constructed using available literature help determine hazard severity of power degradation scenarios. Bayesian failure rate posteriors are constructed for the different components in the traction power system, which are used in a Bayesian decision framework. The results indicate that while most of the components in the traction power architecture of the X-57 Mod. IV are compliant with failure rate requirements generated, the batteries, cruise motors, and cruise motor-inverters do not meet those requirements.
(Georgia Institute of Technology, 2020-06)
Bendarkar, Mayank; Xie, Jiacheng; Briceno, Simon; Harrison, Evan D.; Mavris, Dimitri N.
A typical aircraft certification process consists of obtaining a type, production, airworthiness, and continued airworthiness certificate. During this process, a type certification plan is created that includes the intended regulatory operating environment, the proposed certification basis, means of compliance, and a list of documentation to show compliance. This paper extends previous work to demonstrate a model-based framework for the management of these certification artifacts for normal category airplanes. The developed framework integrates the regulatory rules and approved means of compliance in a single model while using best-practices found in Model-Based Systems Engineering (MBSE) literature. This framework, developed using SysML in MagicDraw captures not just the textual requirements and verification artifacts, but also their relationships and any inherent meta-data properties via custom defined stereotype profiles. Additionally, a simulation capability that automates the extraction and export of the applicable rules (certification basis) and corresponding means of compliance for any aircraft under consideration at the click of a button has been developed. The framework also provides numerous additional benefits to different stakeholders that have been described in detail with examples where necessary.