Papers by Salvatore Ameduri
Actuators
This paper focuses on the development and demonstration of a novel blade morphing system within a... more This paper focuses on the development and demonstration of a novel blade morphing system within a whirl tower facility. The scope is to investigate the behavior of the proposed architecture under representative loads, demonstrating its capability to alter the blade original shape in operation under centrifugal, aerodynamic, and internal forces. The morphing concept was developed inside the European project “Shape Adaptive Blades for Rotorcraft Efficiency”, SABRE, and consists of a shape memory alloy system able to change the original twist law and, in this way, enhance rotor performance at certain specific regimes, such as hover and vertical flight. These phases, indeed, are generally penalized with respect to other more extended flight regimes (cruise). The work starts with an overview of the research in the field of morphing, with specific reference to the researches envisaging rotary wing demonstrations. Then, an overview of the morphing twist concept is provided, with particular...
In a previous paper, the authors dealt with the current showstoppers for morphing systems and wit... more In a previous paper, the authors dealt with the current showstoppers for morphing systems and with the reasons that have inhibited their commercial applicability. In this work, the authors ex-press a critical vision of the current status of the proposed architectures and the needs that should be accomplished to make them viable for installation onboard of commercial aircraft. The distinc-tion is essential because military and civil issues and necessities are very different, and both the solutions and difficulties to be overcome are widely diverse. Yet, still remaining in the civil seg-ment, there can be other differences, depending on the size of the aircraft, from large jets to com-muters or general aviation, in turn classifiable in tourism, acrobatic, ultralight and so on, each with their own peculiarities. Therefore, the paper wants to try to trace a common technology de-nominator, if possible, and envisage a future perspective of actual applications.
Archive of Mechanical Engineering, 2019
An optimal sensor placement methodology is implemented and herein proposed for SHM model-assisted... more An optimal sensor placement methodology is implemented and herein proposed for SHM model-assisted design and analysis purposes. The kernel of this approach analysis is a genetic-based algorithm providing the sensor network layout by optimizing the probability of detection (PoD) function while, in this preliminary phase, a classic strain energy approach is adopted as well established damage detection criteria. The layout of the sensor network is assessed with respect to its own capability of detection, parameterized through the PoD. A distributed fiber optic strain sensor is adopted in order to get dense information of the structural strain field. The overall methodology includes an original user-friendly graphical interface (GUI) that reduces the time-to-design costs needs. The proposed methodology is preliminarily validated for isotropic and anisotropic elements.
Applied Sciences, 2021
Morphing aeronautical systems may be used for a number of aims, ranging from improving performanc... more Morphing aeronautical systems may be used for a number of aims, ranging from improving performance in specific flight conditions, to keeping the optimal efficiency over a certain parameters domain instead of confining it to a single point, extending the flight envelope, and so on. An almost trivial statement is that traditional skeleton architectures cannot be held as a structure modified from being rigid to deformable. That passage is not simple, as a structure that is able to be modified shall be designed and constructed to face those new requirements. What is not marginal, is that the new configurations can lead to some peculiar problems for both the morphing and the standard, supporting, elements. In their own nature, in fact, adaptive systems are designed to contain all the parts within the original geometry, without any “external adjoint”, such as nacelles or others. Stress and strain distribution may vary a lot with respect to usual structures and some particular modification...
Journal of Intelligent Material Systems and Structures, 2019
Active blade twist is an option to increase helicopter performance, for instance moving its condi... more Active blade twist is an option to increase helicopter performance, for instance moving its condition from hovering to cruise. Shape memory alloys give the possibility of realizing compact devices, with high energy density. Several devices have been proposed in literature, showing limitations in terms of effectiveness and necessary room. In this article, the capability of a shape memory alloy torque tube to induce a certain twist law along the blade, while preserving its integrability within the structure, has been exploited. The study refers to a complex theoretical model, made of different specialized modules. In detail, transmitted twist action by the shape memory alloy actuators, aerodynamic effects caused by the induced geometrical change, inertial impact following the motor system integration, and system layout influence on the blade response have been taken into account. Through this model, a parametric investigation has been organized to highlight the importance of selected ...
Actuators, 2019
The work at hand focuses on the modeling, prototyping, and experimental functionality test of a s... more The work at hand focuses on the modeling, prototyping, and experimental functionality test of a smart actuator based on shape memory polymer technology. Particular attention is paid to the specific modeling approach, here conceived as an effective predictive scheme, quick and, at the same time, able to face those nonlinearity aspects, strictly related to the large displacements shape memory polymers usually undergo. Shape memory polymer composites (SMPCs) may play a critical role for many applications, ranging from self-repairing systems to deployable structures (e.g., solar sails, antennas) and functional subcomponents (e.g., pliers, transporters of small objects). For all these applications, it is very important to have an effective tool that may drive the designers during the preliminary definition of the main parameters of the actuation system. For the present work, a SMPC plate sample has been conceived and realized in view of aerospace applications. An external fibre optic sen...
Aerospace, 2018
Within the framework of the Clean Sky-JTI (Joint Technology Initiative) project, the design and t... more Within the framework of the Clean Sky-JTI (Joint Technology Initiative) project, the design and technological demonstration of a novel wing flap architecture were addressed. Research activities were carried out to substantiate the feasibility of morphing concepts enabling flap camber variation in compliance with the demanding safety requirements applicable to the next generation green regional aircraft. The driving motivation for the investigation on such a technology was found in the opportunity to replace a conventional double slotted flap with a single slotted camber-morphing flap assuring similar high lift performances—in terms of maximum attainable lift coefficient and stall angle—while lowering emitted noise and system complexity. The actuation and control logics aimed at preserving prescribed geometries of the device under variable load conditions are numerically and experimentally investigated with reference to an ‘iron-bird’ demonstrator. The actuation concept is based on l...
The work at hand focuses on an adaptive system aimed at improving the soundproof performance of c... more The work at hand focuses on an adaptive system aimed at improving the soundproof performance of car door seals at specific working regimes (cruise), without interfering with the conventional open-closure operations. The idea addresses the necessity of increasing the seal effectiveness, jeopardized by aerodynamic actions more and more important as the speed increase, generating a pressure difference between the internal and the external filed, in the direction of opening the door. To recover this effect, an expanding mechanism was integrated within the seal cavity, driven by an SMA actuator. The material was activated (heated) by Joule effect; its compactness, intrinsic of smart materials, contributed to arrive to a final system characterized by a high level of integrability (expanding cells). In this paper, the development process is described together with the verification activity, aimed at proving the functionality of the realized device. Starting from the industrial requirements...
Health Monitoring of Structural and Biological Systems 2017, 2017
The manufacturing and the preliminary numerical and experimental testing results of a fiber optic... more The manufacturing and the preliminary numerical and experimental testing results of a fiber optic based sensor, able to recognize different load paths, are herein presented. This device is conceived to identify load directions by strain detection along a circumferential geometry. A demonstrator is realized by manufacturing a circular shaped, flexible glass/epoxy laminate hosting the sensible elements. Three loops of optical fiber, laying at different quotes along its thickness, are there integrated. The sensor system is supposed to be bonded on the structural element and then able to follow its deformations under load. The working principle is based on the comparison of the strain paths detected at each fiber optic loop at homologous positions. Rayleigh backscattering optical technology is implemented to measure high spatial resolution strains. A finite element model is used to simulate the sensor behavior and assess its optimal configuration. A preliminary experimental campaign and a numerical correlation are performed to evaluate sensor performance considering in-plane and bending loads.
Aerospace, 2017
In the work at hand, a shape memory alloy (SMA)-based system is presented. The system, conceived ... more In the work at hand, a shape memory alloy (SMA)-based system is presented. The system, conceived for releasing environmental sensors from ground or small unmanned aerial vehicles, UAV (often named UAS, unmanned aerial system), is made of a door, integrated into the bottom of the fuselage, a device distributor, operated by a couple of antagonistic SMA springs, and a kinematic chain, to synchronize the deployment operation with the system movement. On the basis of the specifications (weight, available space, energy supply, sensors size, etc.), the system design was addressed. After having identified the main system characteristics, a representative mock-up was manufactured, featuring the bottom part of the reference fuselage. Functionality tests were performed to prove the system capability to release the sensors; a detailed characterization was finally carried out, mainly finalized at correlating the kinematic chain displacement with the SMA spring temperature and the supplied electrical power. A comparison between theoretical predictions and experimental outcomes showed good agreement.
Aerospace, 2016
Shape memory alloys materials, SMA, offer several advantages that designers can rely on such as t... more Shape memory alloys materials, SMA, offer several advantages that designers can rely on such as the possibility of transmitting large forces and deformations, compactness, and the intrinsic capability to absorb loads. Their use as monolithic actuators, moreover, can lead to potential simplifications of the system, through a reduction of number of parts and the removal of many free play gaps among mechanics. For these reasons, technological aerospace research is focusing on this kind of technology more and more, even though fatigue life, performance degradation, and other issues are still open. In the work at hand, landing gear for unmanned aerial vehicles, UAV, is presented, integrated with shape memory alloys springs as actuation devices. A conceptual prototype has been realized to verify the system ability in satisfying specs, in terms of deployment and retraction capability. Starting from the proposed device working principle and the main design parameters identification, the design phase is faced, setting those parameters to meet weight, deployment angle, energy consumption, and available room requirements. Then, system modeling and performance prediction is performed and finally a correlation between numerical and experimental results is presented.
Journal of Theoretical and Applied Mechanics, 2010
Dynamic behavior of structural elements and their performance in terms of noise and vibration con... more Dynamic behavior of structural elements and their performance in terms of noise and vibration control may be remarkably affected by several pa-rameters, like geometry, material properties, stress field, etc. Ability of adaptively controlling one or more of these parameters leads to a structu-re fitting different requirements in several working conditions. Research activities presented in this work are focused on the design of a fiber-glass laminate structural element with SMA wires embedded along the widest dimension. SMA contraction by the Joule effect heat adduction leads, if suitably constrained on the edges, to an internal stress field with a consequent over-all stiffness increase. The finite element code MSC.NASTRAN is used to simulate the whole system made of a plate and SMA wires controlling elements. The behavior of the SMA is mode-led through the NASTRAN card CELAS that allows one to consider the additional SMA activation stiffness with a suitable "spring" constan...
In this investigation, a sound absorbing material is coupled with an active surface to reduce sou... more In this investigation, a sound absorbing material is coupled with an active surface to reduce sound pressure within an acoustic duct. In this way, an enhancement of the passive foam performance can be observed because of further acceleration of the fluid particles within the foam pores. The experimental activity implements noise control strategies to increase damping within the cavity through acoustic foam with a flexible backing plate, acted by piezoelectric actuators.
Smart Materials, Adaptive Structures and Intelligent Systems, Volume 2, 2008
In this paper we present numerical results concerning vibration reduction of structural-acoustic ... more In this paper we present numerical results concerning vibration reduction of structural-acoustic systems using the synchronized switch control technique. In order to develop a general procedure to model the coupled system (composed by the fluid domain, the structure and the piezoelectric elements), the idea is to use the performances of a standard commercial code such as Nastran. A symmetric reduced order model is derived from a general finite element description through the extraction of appropriate system matrices. For sake of brevity, we just recall that depending upon the choice of fluid field variables, non symmetric formulations are usually obtained (so-called displacement-pressure formulations), the symmetrization can be derived through appropriate choice of fluid field variables [1, 2]. A simple fluid-structure system for which an analytic solution exists will be used to verify the finite element results and to demonstrate the capabilities of the control procedure. Referring...
Journal of Intelligent Material Systems and Structures, 2015
An original Monito-Ring system based on chirped fiber optic and draw tower grating array is prese... more An original Monito-Ring system based on chirped fiber optic and draw tower grating array is presented. The target of this research activity is the realization of a device able to measure deformations of morphing structures which may show large, global displacements due to nonstandard architectures and materials adopted. The occurring strain field results, in turns, much more than the standard sensors can handle. Modulations are then necessary to keep the measured strain low. The proposed solution was conceived to overcome this limitation assuring a suitable reduction of the revealed strain. The concept is made of a flexible ring pinned on a certain number of points to the structural component of interest. The fiber optic is integrated within the ring, and depending on the angular position of the sensor, the ratio between the diameter elongation (i.e. structural strain) and the measured deformation (strain) can be almost arbitrarily set in a large range of values. From each spectrum ...
Smart Structures and Materials 2005: Smart Structures and Integrated Systems, 2005
Aerodynamic control surfaces efficiency is among the major parameters defining the performance of... more Aerodynamic control surfaces efficiency is among the major parameters defining the performance of generic aircraft and is strongly affected by geometric and stiffness characteristics. A target of the '3AS' European Project is to estimate the eventual benefits coming from the adaptive control of the torque rigidity of the vertical tail of the EuRAM wind tunnel model. The specific role of CIRA inside the Project is the design of a device based on the "Smart Structures and Materials" concept, able to produce required stiffness variations. Numerical and experimental investigations pointed out that wide excursions of the tail torque rigidity may assure higher efficiency, for several flight regimes. Stiffness variations may be obtained through both classical mechanic-hydraulic and smart systems. In this case, the attainable weight and reliability level may be the significant parameters to drive the choice. For this reason, CIRA focused its efforts also on the design of devices without heavy mechanical parts. The device described in this work is schematically constituted by linear springs linked in a suitably way to the tail shaft. Required stiffness variations are achieved by selectively locking one or more springs, through a hydraulic system, MRF-based. An optimisation process was performed to find the spring features maximising the achievable stiffness range. Then, the hydraulic MRF design was dealt with. Finally, basing on numerical predictions, a prototype was manufactured and an experimental campaign was performed to estimate the device static and dynamic behaviour.
Journal of Intelligent Material Systems and Structures, 2011
Multiple flight regimes during typical aircraft missions mean that a single unique optimized conf... more Multiple flight regimes during typical aircraft missions mean that a single unique optimized configuration, that maximizes aerodynamic efficiency and maneuverability, cannot be defined. Discrete components such as ailerons and flaps provide some adaptability, although they are far from optimal. Wing morphing can significantly improve the performance of future aircraft, by adapting the wing shape to the specific flight regime requirements, but also represents a challenging problem: the structure has to be stiff to maintain its shape under loads, and yet be flexible to deform without collapse. One solution is to adopt structural elements made of smart materials; Shape Memory Alloys (SMAs) have demonstrated their suitability for many static applications due to their high structural integration potential and remarkable actuation capabilities. In this work, the airfoil camber at the wing trailing edge on a full scale wing of a civil regional transportation aircraft is controlled by subst...
Journal of Intelligent Material Systems and Structures, 2008
During the last decades, some research interest in noise and vibration suppression has been focus... more During the last decades, some research interest in noise and vibration suppression has been focused on a specific control typology, based on semi-active architectures. Related advantages, like low or absent external power supply and intrinsic adaptive capacities, constitute an acceptable compromise between passive and active systems. Among the proposed ones, the so-called Synchronized Switched Shunt Architecture (SSSA) has shown good potential. Theoretical and numerical models able to describe simple systems (concentrated DOFs), controlled by an SSSA were already implemented. Anyway, these models are not immediately applicable to continuous structures (beams, plates, etc.). For this reason, and taking advantage of the previous works, a dedicated simulation code was ideated and implemented. In this article, the cited code was used to predict the benefits due to an SSSA device, applied on a beam element; later on, an experimental campaign was carried out on a dedicated prototype; fina...
Journal of Intelligent Material Systems and Structures, 2011
Aircraft morphing architectures are currently worldwide investigated to enhance performance while... more Aircraft morphing architectures are currently worldwide investigated to enhance performance while reducing weights, volumes and costs. A 3-flap wing, for instance, shall pay a penalty up to 100% due to the insertion of mechanical devices in its body. Moreover, the insertion of cover nacelles disturbs the wing aerodynamics itself. In addition, flapped wings are noisy: deformable, instead of slotted and flapped wings, may lead to significant enhancement also in this field. Within Joint European Initiative on Green Regional Aircraft frame, in cooperation with the University of Naples, Department of Aerospace Engineering, the authors with their colleagues came to the definition of dedicated morphing architectures. This paper focuses on the design and optimization of a morphing architecture based on Shape Memory Alloy (SMA) technology, aimed at increasing airfoil trailing edge curvature. The deformable rib system is constituted of four elastic elements. The aerodynamic loads were compute...
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Papers by Salvatore Ameduri