1,720,974 research outputs found
Actuation System Design for a Morphing Aileron
No full textIn the field of European and International morphing structures projects, the CRIAQ MD0-505 enables collaboration among Italian and Canadian research centers and industries paying particular attention to the development of innovative design in the area of adaptive technologies. The main project goals involve the design of a wing trailing edge device capable to improve aerodynamic efficiency in all the flight envelope leading to fuel consumption reduction with positive impact on aircraft weight. This paper deals with the design and modeling of a novel actuation system of a full scale morphing aileron for a regional aircraft wing. The proposed aileron architecture is characterized by segmented adaptive ribs. Each rib is composed of two movable blocks connected by means of rotational hinges in which are housed bearings and bushing in a finger-like mechanism. Rib actuation is guaranteed by an actuation system composed of a dedicated kinematic chain derived from a quick-return mechanism. In order to achieve the aileron target shapes, the system is driven by a set of servo-rotary electro mechanical actuators that permit a highly integrated design which lays the groundwork for the technological transition from the torque shaft to the distributed actuation
architecture
Distributed actuation concepts for a morphing aileron device
No full textThe actuation mechanism is a crucial aspect in the design of morphing structures due to the very stringent requirements involving actuation torque, consumed power, and allowable size and weight.
In the framework of the CRIAQ MD0-505 project, novel design strategies are investigated to enable morphing of aeronautical structures. This paper deals with the design of a morphing aileron with the main focus on the actuation technology. The morphing aileron consists of segmented ’finger-like’ ribs capable of changing the airfoil camber in order to match target aerodynamic shapes. In this work, lightweight and compact actuation kinematics driven by electromechanical actuators are investigated to actuate the morphing device. An unshafted distributed servo-electromechanical actuation arrangement is employed to realise the transition from the baseline configuration to a set of target aerodynamic shapes by also withstanding the aerodynamics loads. Numerical investigations are detailed to identify the optimal actuation architecture matching as well as the system integrability and structural compactness
Preliminary Design of an Adaptive Aileron for Next Generation Regional Aircraft
No full text“Inspiration from nature” is the key words that lies behind the morphing idea. Just as bird helped to inspire the design of the warping mechanism of the Wright Flyer, nature offers a philosophy inspiration for morphing wing design. Since aviation origin, a connection between bio-inspiration and aeronautical engineering can be found which has led through years at the current idea of a morphing wing as a mechanism capable to adapt its shape as well as the flight conditions change. Design of morphing wings at increasing TRL is common to several research programs worldwide, especially aimed at improving their associated benefits (optimize aerodynamic efficiency, fuel consumption reduction, decrease of COx and NOx emission, etc.) and overcoming classical limits (increasing system complexity, certification, reliability and so on). In this framework, the CRIAQ MD0505 project was launched; a joint research program between Canadian and Italian academies, research centers and leading industries. The target of this research cooperation is the development of combined smart structures systems on a full scale wing tip of a next generation regional aircraft. The complex device combines a modifiable airfoil thickness with a camber morphing aileron. This paper focuses on the preliminary design and the numerical modeling of the aileron architecture. The structural layout consists of a number of deformable ribs, each made of three consecutive blocks connected each other by hinges. Further cross connections between pair of elements, make the system a SDOF finger-like mechanism. The aileron is moved by servo rotary load bearing actuators which drive a kinematic chain and sustain the external aerodynamic pressure distribution. A FE model of the entire architecture was released to verify the structural integrity under prescribed operational conditions
Preliminary design of a compliant mechanism for rib morphing implementation
No full textAdaptive structures have been individuated as a topic of great interest for researchers working in aeronautical field. This is mainly due to the several benefits which can be obtained by implementing morphing technology in aircraft design; novel structures, in perspective fully-adaptable to different flight conditions, may in fact bring many advantage at system level: from noise emission reduction to aerodynamic efficiency enhancement and fuel-burn optimization.
Such an approach, in spite of related benefits, presents a challenging problem: the same structure has to be stiff enough to withstand external aerodynamic loads without appreciable deformations while being flexible enough to dramatically change its external shape. In the framework of the CRIAQ MDO505 project, the first joined program between Canadian and Italian research centers, academies and leading industries, the authors addressed the design assessment of a novel rib architecture enabling the camber variation of the aileron airfoil through a compliant mechanism. The architecture allows controlled aileron’s shape modification in order to improve the wing tip / aileron aerodynamic efficiency at low subsonic speed. On the base of specific target shapes and related external loads, the structural layout of the device was preliminarily defined. The reference geometry was tailored for a full scale wing of a civil regional transportation aircraft, where the conventional aileron component was substituted by the morphing device. Each aileron rib was composed of multiple, suitably shaped, rigid elements whose relative rotations were driven by means of an actuated linear spring. Advanced FE analyses were carried out in order to properly size the compliant mechanism and the actuation chain.
System’s capability to reproduce target morphed shapes under the action of aerodynamic loads was successfully proved on the base of FE analyses outcomes
Preliminary design of a novel morphing rib architecture based on lumped elastic properties
No full textAircraft wings are usually optimized for a specific design point. However, since they operate in a wide variety of flight regimes, some of these have conflicting impacts on aircraft design, as an aerodynamically efficient configuration in one instance may perform poorly in others.
Ideally rigid, non-deformable aircraft structures preclude any adaptation to changing conditions. Alternatively, morphing wings can provide adaptive capabilities to maximize aircraft performance in every flight condition. It is therefore not surprising that several research programs are currently running worldwide to explore the feasibility of morphing concepts especially with reference to their benefits/drawbacks ratio. Among these, the CRIAQ MD0505 project was launched; the project represents the first joined research program between Canadian and Italian academies, research centres and leading industries. Referring to the wing tip of a regional transportation aircraft, the program addresses the implementation of combined smart structures specifically conceived to optimize the aerodynamic efficiency; more in detail an adaptive-bump configuration is investigated for the upper skin of the wing box (to control the separation point between laminar and turbulent flow) and a variable camber aileron architecture. In this framework the authors focused on the design of a morphing aileron characterized by active ribs enabling the in-flight modification of external airfoil shape. On the base of specific requirements regarding target morphing shape to be matched and loads to be withstood, an innovative architecture was developed for the active rib; the rib is chordwise divided in three main blocks connected by crossed springs which assure relative rotation among blocks while contributing to the absorption of external solicitations.. In this paper, the preliminary design phase of the rib has been outlined, from the concept definition up to the assessment of structural properties and actuation system through advanced FE analyses
Flutter analysis of a large aircraft model for wind tunnel tests
No full textIn the framework of the GRA low noise domain, the WENEMOR project was launched to carry-out aero-acoustic measurements on a wind tunnel test model representative of different aircraft configurations equipped with rear-fuselage open rotor systems, operating in both pusher and tractor modes. Due to the large scale of the test model (1:7.5 of the actual dimension), to its elasticity and to the fully powered propulsive system, it was considered mandatory to address aeroelastic instability analyses in order to assure tests safety.
Rational approaches were implemented in order to simulate the effects induced by variations of design stiffness and damping values, especially for the engines/pylons connection; reliable aeroelastic models and advanced computational strategies were properly implemented to enable fast flutter analyses covering several configuration cases in terms of power plant installation and tail empennages layout.
Flutter and divergence clearance was finally demonstrated up to four times the maximum flow speed expected during wind tunnel test campaign
Validation of a smart structural concept for wing-flap camber morphing
No full textThe study is aimed at investigating the feasibility of a high TRL solution for a wing flap segment characterized by morphable camber airfoil and properly tailored to be implemented on a real-scale regional transportation aircraft. On the base of specific aerodynamic requirements in terms of target airfoil shapes and related external loads, the structural layout of the device was preliminarily defined. Advanced FE analyses were then carried out in order to properly size the load-carrying structure and the embedded actuation system. A full scale limited span prototype was finally manufactured and tested to:
(1) demonstrate the morphing capability of the conceived structural layout;
(2) demonstrate the capability of the morphing structure to withstand static loads representative of the limit aerodynamic pressures expected in service;
(3) characterize the dynamic behavior of the morphing structure through the identification of the most significant normal modes.
Obtained results showed high correlation levels with respect to numerical expectations thus proving the compliance of the device with the design requirements as well as the goodness of modeling approaches implemented during the design phase
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Exploitation of adaptive trailing edge architectures to small aircraft
No full textAirfoil camber adaptation may be the key for the performance
improvement of wings for many specific applications, including
shorter take-off distance, compensation of weight variation and
so on. Following the successful experiences gained in
SARISTU, where an adaptive trailing edge device was
developed for medium to large size commercial aircraft, the
authors propose to exploit the developed architecture to a small
aircraft wing. The basic reasons behind that mainly rely on the
associated possibility to access easier implementation onto a
real aircraft instead of referring to wing segments for wind
tunnel or ground tests. In this way, many operative problems are
faced, that would be otherwise neglected in usual lab
experimentation. First of all, the integration of the proposed
device onto a flying machine, that in turn pose the problem of
facing the interface with the existing systems. Secondly, the
necessity of including the device into the flap while fully
preserving its current functionality. Furthermore, the necessity
of developing a robust design process that allows having the
release of the permit-to-fly. Each of the above steps, nonexhaustive
in illustrating the difficulty of the addressed
challenge, is structured in many other sub-segments, ranging
from a suitable FHA analysis to a full re-design of the existing
high lift systems or the adaptation of the architecture of the
reference morphing trailing edge itself. This last item poses the
classical challenge of the scaling issues, requiring the structural
and the actuation subsystems to entirely fit into the new
geometry. The objective of the present research is then to verify
the feasibility of applying a certain architectural morphing
philosophy onto a real aircraft, taking into account all the
operational difficulties related to such an operation. This paper
reports the activities related to the exploitation of the reference
adaptive structural architecture, to the geometry of a flap of a
small aircraft. In detail, the system layout is presented, followed
by a FE analysis of the structural system under the operational
loads and an estimation of the weight penalty associated to this
transformation. Interfaces of the flap system with the main
aircraft body are considered as constraints to the design
development, so that the only flap is affected
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