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Overview of the Integrated Adaptive Wing Technology Maturation Wind-Tunnel Test Objectives
... The test plan for this wing was divided into two phases, phase 1 consists of the validation of the open-loop characterization of the wing. Phase 2 aims to test controllers for drag optimization, maneuver and gust load alleviation, and active flutter suppression [24]. ...
High aspect ratio flexible wing aircraft present very complex and coupled structural and flight dynamics. This research describes a bottom-to-top validation process for this type of wing. This procedure starts with static, followed by ground vibration and wind tunnel tests. The concept of this approach is to first validate the structural and aeroelastic models before addressing the full flying vehicle. The experimental data was used to tune the structural model of a flexible flying demonstrator called TU-Flex. This aircraft was designed as a flying lab capable of recording coupled flight dynamic data of a flexible aircraft with a transport/airliner configuration. Three software were used to design the wing and to define the experimental test cases: NASTRAN, Loads Kernel, and ModSiG. The gathered data permitted tuning and showing the accuracy of the structural model. It also allows for finding inaccuracies in the aerodynamic and aeroelastic models for further tuning. The models are capable of capturing the overall aeroe-lastic trend nevertheless, fine tuning is now necessary. Therefore, the proposed process seems adequate to collect all necessary data to tune aeroelastic models within the process to prepare the models for the full flying vehicle.
... T he NASA Advanced Air Transport Technology (AATT) project aims to develop concepts and technologies that improve the energy efficiency and lessen the environmental impact of fixed-wing transport aircraft [1]. One current effort within AATT is the Integrated Adaptive Wing Technology Maturation (IAWTM) sub-project, which is a collaboration involving multiple NASA centers and Boeing [2]. The sub-project will test a side wall-mounted, half-span, wind tunnel test article based on the NASA Common Research Model (CRM) [3] but with an increased wing aspect ratio and flow-through engine nacelles. ...
The design of an active flutter suppression (AFS) control law for upcoming wind tunnel tests in the Transonic Dynamics Tunnel (TDT) at the NASA Langley Research Center (LaRC) with the Integrated Adaptive Wing Technology Maturation (IAWTM) sub-project is presented. The test article is a highly flexible half-span model of a transport airplane and tests will focus on the transonic regime. The control law is based on the concept of collocation, sometimes called identically located accelerometer and force (ILAF), which uses local velocity feedback to increase damping for all aeroelastic modes. A multiple-input multiple-output (MIMO) extension of this architecture is used for performance and robustness improvements. Simulation results and analyses showed that the proposed control law stabilizes the design models over the conditions planned for experimental testing and successfully extends the flutter boundary to higher Mach numbers and dynamic pressures.
View Video Presentation: https://doi.org/10.2514/6.2022-0004.vid OpenVSP is a parametric geometry tool for creating 3D models during the conceptual design process. It supports several engineering analyses and writes out files that can feed many other analysis tools. Over the years, OpenVSP and its predecessors have evolved from something useful for creating a model illustrating an aircraft concept to a geometry and analysis engine at the center of many aircraft design frameworks and workflows. OpenVSP has been widely adopted by established aerospace players including industry, government, and academia as well as innovative startups across the Mach-altitude envelope developing systems from UAV's, eVTOL, civil supersonics, hypersonics, space launch, and small satellites.
Since its introduction, the NASA Common Research Model has proved a useful aerodynamic benchmark for predicting computational-fluid-dynamics-based drag and aerodynamic design optimization. The model was originally conceived as a purely aerodynamic benchmark, and as such the wing geometry corresponds to the deflected shape at its nominal 1g flight condition. However, interest has been growing to extend this model to aeroelastic studies. Unfortunately, because of its predefined deflection, the model is not suitable for aeroelastic analysis and design. To address this issue, an undeflected Common Research Model is defined through an inverse design procedure that includes the outer mold line geometry of the undeflected wing and the corresponding internal wingbox structure. Additionally, because modern transport aircraft are trending toward higher-aspect-ratio wing designs, a higher-aspect-ratio variant of the Common Research Model wing is developed to assess next-generation wing designs. This variant has an aspect ratio of 13.5 and is designed by using buffet-constrained multipoint aerostructural optimization. The purpose of these models is to provide publicly available benchmarks for aeroelastic wing analysis and design optimization