Wind Tunnel Testing of a Lightweight One-Quarter-Scale Actuator Utilizing Shape Memory Alloy

Ruggeri, Robert T.; Arbogast, D. J.; Bussom, Richard

doi:10.2514/6.2008-2279

Cited by 7 publications

(7 citation statements)

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“…The actuator was tested in 2007 using a ¼ scale three-blade hub assembly mounted on the Boeing Advanced Rotor Test Stand. The wind tunnel test was a high-fidelity assessment of the SMA actuator (Ruggeri et al, 2008a) and represents one of the first attempts to produce a high-torque SMA actuator for the rotor environment. The actuator provided approximately 250 twist transitions during 75 h of testing with no loss of performance or operational anomalies.…”

Section: Shape Memory Alloy Actuation Of Twist and Rigid-body Rotationmentioning

confidence: 99%

A Review of Morphing Aircraft

Barbarino

Bilgen

Ajaj

et al. 2011

Journal of Intelligent Material Systems and Structures

1,140

647

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Aircraft wings are a compromise that allows the aircraft to fly at a range of flight conditions, but the performance at each condition is sub-optimal. The ability of a wing surface to change its geometry during flight has interested researchers and designers over the years as this reduces the design compromises required. Morphing is the short form for metamorphose; however, there is neither an exact definition nor an agreement between the researchers about the type or the extent of the geometrical changes necessary to qualify an aircraft for the title ‘shape morphing.’ Geometrical parameters that can be affected by morphing solutions can be categorized into: planform alteration (span, sweep, and chord), out-of-plane transformation (twist, dihedral/gull, and span-wise bending), and airfoil adjustment (camber and thickness). Changing the wing shape or geometry is not new. Historically, morphing solutions always led to penalties in terms of cost, complexity, or weight, although in certain circumstances, these were overcome by system-level benefits. The current trend for highly efficient and ‘green’ aircraft makes such compromises less acceptable, calling for innovative morphing designs able to provide more benefits and fewer drawbacks. Recent developments in ‘smart’ materials may overcome the limitations and enhance the benefits from existing design solutions. The challenge is to design a structure that is capable of withstanding the prescribed loads, but is also able to change its shape: ideally, there should be no distinction between the structure and the actuation system. The blending of morphing and smart structures in an integrated approach requires multi-disciplinary thinking from the early development, which significantly increases the overall complexity, even at the preliminary design stage. Morphing is a promising enabling technology for the future, next-generation aircraft. However, manufacturers and end users are still too skeptical of the benefits to adopt morphing in the near future. Many developed concepts have a technology readiness level that is still very low. The recent explosive growth of satellite services means that UAVs are the technology of choice for many investigations on wing morphing. This article presents a review of the state-of-the-art on morphing aircraft and focuses on structural, shape-changing morphing concepts for both fixed and rotary wings, with particular reference to active systems. Inflatable solutions have been not considered, and skin issues and challenges are not discussed in detail. Although many interesting concepts have been synthesized, few have progressed to wing tunnel testing, and even fewer have flown. Furthermore, any successful wing morphing system must overcome the weight penalty due to the additional actuation systems.

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Section: Shape Memory Alloy Actuation Of Twist and Rigid-body Rotationmentioning

confidence: 99%

A Review of Morphing Aircraft

Barbarino

Bilgen

Ajaj

et al. 2011

Journal of Intelligent Material Systems and Structures

1,140

647

View full text Add to dashboard Cite

show abstract

“…Perhaps the largest effort devoted to large twist changes has been the ONR-funded Reconfigurable Rotor Blade program with Boeing serving as the prime contractor. In this effort, an SMA actuator (Clingman and Jacot, 2000;Ruggeri et al, 2003;Caldwell and Gutmark, 2007;Ruggeri et al, 2008) is used to change the twist of a V-22 Osprey blade, but despite the large actuator weight and the power requirements, the twist change of the baseline V-22 blade is considerably smaller (of the order of 2 ) (Ruggeri et al, 2008), than desired. Thus, there remains a strong requirement for new technologies that can yield large rotor blade twist changes at relatively modest actuation force and power requirements, while ensuring a sufficient degree of torsional stiffness in the blade.…”

Section: Nomenclaturementioning

confidence: 99%

Actuation Requirements of a Warp-Induced Variable Twist Rotor Blade

Mistry

Gandhi

Nagelsmit

et al. 2011

Journal of Intelligent Material Systems and Structures

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This article examines a warp-induced twist concept to obtain quasi-static large amplitude twist changes of helicopter or tiltrotor blades for performance benefits over diverse operating conditions. The presented concept has a cylindrical spar with rotating ribs which are attached to the blade skin that is slit along the trailing edge. Warping the skin then produces twisting of the blade section. Warp actuation is implemented by rotating a threaded rod assembly attached to the interior of the upper and lower skin near the trailing edge. Due to the slit at the trailing edge, the blade is soft in torsion during actuation, but is effectively a closed section due to the threaded rod assembly when in power off state. A prototype (NACA 0012, 10.75 in chord, 42 in span) based on this concept was built and tested for both the warp-twist relationship and the actuation torque requirements for producing the twist of the blade (up to ±18°). The finite element model developed in this article correlated very well with the experimental measurements made on the prototype. The validated finite element model is further used to conduct a study to understand the effect of various structural parameters on the system behavior.

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“…Morphing structures relying on shape-memory alloys [9][10][11][12][13] are inherently characterized by comparatively long time scales, owing to the slow response time characteristic of the smart materials-based actuators. They are thus not well suited to replace primary flight controls; however, they can be used to adapt to different, slowly changing flight conditions.…”

Section: Introductionmentioning

confidence: 99%

Aerostructural Performance of Distributed Compliance Morphing Wings: Wind Tunnel and Flight Testing

et al. 2016

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The aerodynamic and structural performance of a morphing wing concept, based on fully compliant structures and actuated by closed-loop controlled solid state piezoelectric actuators, is investigated numerically and experimentally. The morphing wings are designed for a 1.75-m-span unmanned aerial vehicle operating at up to 30 m∕s, following lightweight aeronautical construction principles. The goal of providing roll controllability exclusively through morphing is achieved with a concurrent aerostructural optimization, considering static and dynamic aeroelastic effects. The aeroelastic response of the wings is experimentally assessed through wind tunnel tests, performed at different speeds, angles of attack, and actuation levels. The test campaign confirms the ability to achieve lift and rolling moment variations while maintaining a high aerodynamic efficiency, and the results closely match the numerical predictions. An 8-min flight test is performed by replacing the unmanned aerial vehicle wings with the morphing system, demonstrating the capabilities of the concept in its operational environment. This experimental assessment confirms the performance of the design, its robustness, and the possibility of implementing the morphing concept and the required high-voltage control system in small unmanned aerial vehicles. Ultimately, the results show the possibility of replacing the conventional ailerons of similarly sized airplanes with the proposed solution, achieving significant efficiency improvements while guaranteeing controllability.

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Wind Tunnel Testing of a Lightweight One-Quarter-Scale Actuator Utilizing Shape Memory Alloy

Cited by 7 publications

References 0 publications

A Review of Morphing Aircraft

A Review of Morphing Aircraft

Actuation Requirements of a Warp-Induced Variable Twist Rotor Blade

Aerostructural Performance of Distributed Compliance Morphing Wings: Wind Tunnel and Flight Testing

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