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, thes...

A Review of Morphing Aircraft

Shape morphing of aircraft wing: Status and challenges

The recently completed DARPA/AFRL/NASA Smart Wing program, performed by a team led by Northrop Grumman Corporation (NGC), addressed the development and demonstration of smart materials based concep...

Overview of the DARPA Smart Wing Project

With increasing size of wind turbines, new approaches to load control are required to reduce the stresses in blades. Experimental and numerical studies in the fields of helicopter and wind turbine blade research have shown the potential of shape morphing in reducing blade loads. However, because of the large size of modern wind turbine blades, more similarities can be found with wing morphing research than with helicopter blades. Morphing technologies are currently receiving significant interest from the wind turbine community because of their potential high aerodynamic efficiency, simple construction and low weight. However, for actuator forces to be kept low, a compliant structure is needed. This is in apparent contradiction to the requirement for the blade to be load carrying and stiff. This highlights the key challenge for morphing structures in replacing the stiff and strong design of current blades with more compliant structures. Although not comprehensive, this review gives a concise list of the most relevant concepts for morphing structures and materials that achieve compliant shape adaptation for wind turbine blades.

Review of morphing concepts and materials for wind turbine blade applications

Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human–robot interaction and locomotion. Although field applications have emerged for soft manipulation and human–robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This paper aims to provide a reference guide for researchers approaching mobile soft robotics, to describe the underlying principles of soft robot locomotion with its pros and cons, and to envisage applications and further developments for mobile soft robotics.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2017.0101

Fundamentals of soft robot locomotion.

The DARPA/AFRL/NASA Smart Wing program, led by Northrop Grumman Corporation (NGC) under the DARPA Smart Materials and Structures initiative, addressed the development of smart technologies and demonstration of relevant concepts to improve the aerodynamic performance of military aircraft. In Phase 2, Test 2 of the program, the main objective was to demonstrate high-rate actuation of hingeless, spanwise, and chordwise deformable control surfaces using smart materials-based actuators on a 30% scale, full span wind tunnel model of a proposed NGC uninhabited combat air vehicle (UCAV). A minimum actuation rate of 25° flap deflection in 0.33 s, producing a slew rate of 75°/s, was desired. This slew rate is representative of many operational military aircrafts with hinged control surfaces. Numerous trade studies were performed on a variety of smart materials and flexible structure configurations before arriving at the final trailing edge structure design that consisted of a flexcore center and elastomeric outer s...

Development of High-rate, Adaptive Trailing Edge Control Surface for the Smart Wing Phase 2 Wind Tunnel Model:

Electrical power distribution for recently developed smart actuators becomes an important air-vehicle challenge if projected smart actuation benefits are to be met. Among the items under development are variable shape inlets and control surfaces that utilize shape memory alloys (SMAs); full-span, chord-wise and span-wise contouring trailing control surfaces that use SMA or piezoelectric materials for actuation; and other strain-based actuators for buffet load alleviation, flutter suppression and flow control. At first glance, such technologies afford overall vehicle performance improvement. However, integration system impacts have yet to be determined or quantified. Power systems to support smart structures initiatives are the focus of the current paper. The paper has been organized into five main topics for further discussion: (1) air-vehicle power system architectures – standard and advanced distribution concepts for actuators, (2) smart wing actuator power requirements and results highlighting wind tun...

/pdf/power-systems-and-requirements-for-integration-of-smart-1o8nyb0exv.pdf

Power Systems and Requirements for Integration of Smart Structures into Aircraft

Building on the research performed during the DARPA/AFRL/NASA Smart Wing Phase 1 program (Kudva, J.N. et al. (July 1999). Overview of the DARPA/AFRL/NASA Smart Wing Program, SPIE Symposium on Smart Structures and Materials, Newport Beach, CA, Vol. 3674, pp. 230 6; Martin, C.A. et al. (1999). Smart Materials and Structures Smart Wing Phase 1 Final Report, AFRL-ML-WP-TR-1999-4162, Air Vehicles Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH.) sought to improve vehicle aerodynamic efficiency using control surfaces actuated by smart materials, the goal of the Phase 2 effort was to develop larger scale, smart hingeless control surfaces capable of high-rate actuation and quantify their performance benefits at test conditions representative of operational flight environments. To achieve this goal, a 30-percent geometric scale, full-span wind tunnel model of a proposed Northrop Grumman Corporation (NGC) Uninhabited Combat Air Vehicle (UCAV) was designed and tested. The model incorp...

Design, Fabrication, and Testing of a Scaled Wind Tunnel Model for the Smart Wing Project:

Design of advanced aircraft structures requires information about the effects of constraints and performance parameters on the details of the optimized structure. Desire for radical increases in vehicle performance, fueled by advances in the field of smart structures, such as adaptive wing and conformal flaps, and advances in structural technology (e.g., composite materials and active materials), challenge existing structural design concepts and processes 1 . Design processes which work from a given set of performance requirements and are based on experiential trends in aircraft performance may not be useful for innovative concepts since the technologies considered to improve aerodynamic, structural, material, or controls performance are multidisciplinary in nature. The overall process of conceptual design for such concepts must therefore take a formal, analytical approach that integrates structural information earlier in the design process 2 . Because the structural technology concepts that best fulfill the mission are dependent on the active structural loads and constraints and the customer may be interested in understanding tradeoffs in the design requirements and objectives, it is necessary to gather information about the effects of constraints and performance objectives on the optimized structural design. This paper will discuss and illustrate part of a formal conceptual design process that addresses the evaluation of the effects of constraints and performance objectives on the optimized structure. The particular problem being studied is the wing structural design for the SensorCraft vehicle 3 , an

Christopher A. Martin

Papers

Development of High-rate, Adaptive Trailing Edge Control Surface for the Smart Wing Phase 2 Wind Tunnel Model:

Power Systems and Requirements for Integration of Smart Structures into Aircraft

Design, Fabrication, and Testing of a Scaled Wind Tunnel Model for the Smart Wing Project:

Sensitivity of Optimized Structures to Constraints and Performance Requirements for the SensorCraft ISR Platform

A smarter transition for smart technologies