Framework to Assess Effects of Structural Flexibility on Dynamic Loads Developed in Maneuvering Aircraft

AIAA Scitech 2021 Forum

Harrison

et al. 2021

Self Cite

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 −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.

Section: Fig 10 Delphi Frameworkmentioning

confidence: 99%

Section: Appendixmentioning

confidence: 99%

Evaluation of Off-Nominal Performance and Reliability of a Distributed Electric Propulsion Aircraft during Early Design

Bendarkar

AIAA Scitech 2021 Forum

Harrison

et al. 2021

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“…The following procedure is typically adopted to size the structural components: 1) static and dynamic maneuvers are first simulated by coupling aerodynamics, structural dynamics, flight mechanics, and controls [33][34][35]; 2) then, the dynamic and static loads together are converted into a set of critical static load cases [36,37]; and finally, 3) the structure is approximately represented as either a shell model [38][39][40] or a beam model [41][42][43][44] and sized for critical static load cases. The structural weight estimation model computes the aircraft-level mass properties specified by 10 scalars: mass, three components of the center of gravity w.r.t.…”

Section: Structural Componentsmentioning

confidence: 99%

Large-Scale Multidisciplinary Design Optimization of an eVTOL Aircraft using Comprehensive Analysis

AIAA SCITECH 2023 Forum

Ruh

Joshy

et al. 2023

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“…A framework named Dynamic Environment for Loads Prediction and Handling Investigation (DELPHI) is under development at ASDL following prior work in [25][26][27]. An aircraft in DELPHI is defined by 1) mass properties (Section A), 2) aerodynamic characteristics (Section B) which describe the total forces and moments at a reference point as a function of aircraft states and control surface deflections, and 3) propulsive performance (engine deck) which define the propulsive loads at the reference point as a function of altitude, Mach number and throttle.…”

Section: E Dynamic Loadsmentioning

confidence: 99%

“…The regulations state that the flexibility of the structure must be accounted for while performing the maneuvers. One such study was performed in a prior work by Sarojini et al [27], where the structure was represented as beams and coupled with the aerodynamics and flight dynamics. The DELPHI framework described in Section II-E will be extended to allow for flexible flight dynamics.…”

Section: Future Workmentioning

confidence: 99%

A Certification-Driven Platform for Multidisciplinary Design Space Exploration in Airframe Early Preliminary Design

Aiaa Aviation 2020 Forum

Xie

Cai

et al. 2020

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Following the conceptual phase of aircraft design, sizing and performance estimations shift from historical-based empirical equations to physics-based simulations. The initial aircraft configuration is refined with a larger number of objectives and requirements, and certification regulations play a critical role in defining these. Analysis tools in the early phases of preliminary design have an important trade-off between accuracy, complexity, and computational efficiency. A number of analysis frameworks currently exist with varying levels of fidelity, multidisciplinary coupling, and limitations in the number of disciplines, degrees of freedom, and requirements they are able to implement. To enable efficient design space exploration (DSE), this paper proposes an integrated preliminary design framework that couples aerodynamics, structures, subsystems, aircraft performance, flight dynamics, and certification testing at varying levels of fidelity. This framework serves as a numerical testbed that can be used to explore the aircraft configuration and disciplinary design spaces, strength of disciplinary couplings, and propagate disciplinary uncertainties across the entire aircraft system. The framework is demonstrated using the horizontal tail of a large twin-aisle aircraft as a test case.