April 2014 

NASA/TM–2014-218252 

Aeroelastic Tailoring of Transport Aircraft 

Wings: State-of-the-Art and Potential 

Enabling Technologies 

Christine V. Jutte 

Craig Technologies, Inc., Cape Canaveral, Florida 

Bret K. Stanford 

Langley Research Center, Hampton, Virginia 
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April 2014 

NASA/TM–2014-218252 

Aeroelastic Tailoring of Transport Aircraft 

Wings: State-of-the-Art and Potential 

Enabling Technologies 

Christine V. Jutte 

Craig Technologies, Inc., Cape Canaveral, Florida 

Bret K. Stanford 

Langley Research Center, Hampton, Virginia 

.
Available from: 

NASA Center for AeroSpace Information 

7115 Standard Drive 

Hanover, MD 21076-1320 

443-757-5802 
Aeroelastic Tailoring of Transport Aircraft Wings: 

State-of-the-Art and Potential Enabling Technologies 

Christine V. Jutte 

Craig Technologies, Inc. 

Bret K. Stanford 

NASA Langley Research Center 

This paper provides a brief overview of the state-of-the-art for aeroelastic tailoring of 

subsonic transport aircraft and offers additional resources on related research efforts. 

Emphasis is placed on aircraft having straight or aft swept wings. The literature covers 

computational synthesis tools developed for aeroelastic tailoring and numerous design 

studies focused on discovering new methods for passive aeroelastic control. Proprietary 

information, which is not available in the open literature, is understandably not included. 

Several new structural and material technologies are presented as potential enablers of 

aeroelastic tailoring, including selectively reinforced materials, functionally graded 

materials, fiber tow steered composite laminates, and various nonconventional structural 

designs. In addition, smart materials and structures whose properties or configurations 

change in response to external stimuli are presented as potential active approaches to 

aeroelastic tailoring. 

1 Introduction 

The Fixed Wing project of NASA’s Fundamental Aeronautics program has been actively developing 

manufacturing techniques, new materials, and structural design tools to address a suite of technical challenges facing 

current and future subsonic transport aircraft. A primary challenge of the Fixed Wing project is to reduce fuel burn 

in transport aircraft. Targeted design advancements include wing structural weight reduction and increased wing 

aspect ratio to decrease lift-induced drag. High aspect ratio wings operating at minimum weight are typically highly 

flexible structures prone to aeroelastic instabilities. Therefore, aeroelastic tailoring is one important approach to 

achieve light weight airframe designs. Aeroelastic tailoring was defined as “the embodiment of directional stiffness 

into an aircraft structural design to control aeroelastic deformation, static or dynamic, in such a fashion as to affect 

the aerodynamic and structural performance of that aircraft in a beneficial way,” [1]. More simply, aeroelastic 

tailoring has also been defined as “passive aeroelastic control” [2]. In addition to stiffness, mass distribution also 

has an effect on the dynamic properties of a structure, although it is typically considered less during initial design 

efforts and more to mitigate harmful unforeseen dynamics found later in the design process. Weight minimization is 

only one objective associated with aeroelastic tailoring; other objectives include, but are not limited to, flutter, 

divergence, stress, roll reversal, control effectiveness, lift, drag, skin buckling, and fatigue. 

The goal of this paper is to provide a brief overview on the state-of-the-art of aeroelastic tailoring for subsonic 

transport aircraft and to guide the reader to additional resources on related research efforts. Research areas are 

broken down as follows: 

• Aeroelastic tailoring methods 

o Computational synthesis tools 

o Global (uniform) tailoring 

o Local (non-uniform) tailoring 

o Additional tailoring approaches 

• Potential material/structural enabling technologies 

o Passive technologies, including selectively reinforced materials, functionally graded materials, 

fiber tow steering within composite laminates, and nonconventional structural designs 

o Active technologies 

 
2

Material/structural enabling technologies for aeroelastic tailoring pertain to materials and structural designs that can 

directly affect a wing’s stiffness, mass, or aerodynamics. The amount of research already dedicated to aircraft 

aeroelastic tailoring is substantial; furthermore, the extent of the research related to potential solutions or 

technologies for aeroelastic tailoring is even greater. Therefore, a limited timeframe of a few months was dedicated 

to perform a brief yet sufficient literature survey to guide NASA’s current research in wing weight reduction. 

Proprietary information (which is not available in the open literate) is understandably not included. Of the research 

papers found, only the most relevant, which are usually the most recent, are included here. 

Emphasis is placed on passive solutions to aeroelastic control of subsonic transport aircraft having straight or aft 

swept wings. Papers that approach aeroelastic tailoring in a more detailed and possibly localized manner (as 

opposed to globally reorienting the composite laminate of a wing skin, e.g.) are more heavily scrutinized and 

summarized here. 

2 Aeroelastic Tailoring 

According to Shirk et al. [1], the first record of aeroelastic tailoring is from 1949 by Munk [3] who oriented the 

grain of his wooden propeller blade to create desirable deformation couplings when operated. In the late 1960s, 

there was a thrust in aeroelastic tailoring research, which has continued fairly steadily through to today. The 

forward swept wings of the X-29 and the Active Aeroelastic Wing are two aeroelastic tailoring examples 

highlighted by Weisshaar [2]. Today the use of composite materials is becoming more prevalent in transport aircraft, 

including the 787, the A380, and the upcoming A350. Enhanced fabrication processes for composite laminates offer 

new design possibilities that have not been fully exploited for optimal aeroelastic performance and weight savings. 

Continued research into advanced aircraft materials and structures is likely to lead to new aeroelastically tailored 

designs. Table 1 lists papers on the broader subjects of aeroelastic tailoring, aeroelasticity, airframe materials, 

and/or airframe structural design. For additional information, the ‘author’ column also includes the number of 

references that were cited in a particular work. 

Table 1. Papers on the broader subjects of aeroelastic tailoring, aeroelasticity, airframe materials, and/or 

airframe structural design. 

Year [Ref] Authors (#Cited works) Title 

1986 [1] Shirk, Hertz, Weisshaar 

(89) 

Aeroelastic Tailoring – Theory, Practice, and Promise 

2000 [4] Bucci, Warren, Starke 

(33) 

Need for New Materials in Aging Aircraft Structures 

2002 [5] Kuzmina, Amiryants, 

Schweiger, Cooper, 

Amprikidis, Sensberg (7) 

Review and Outlook on Active and Passive Aeroelastic Design 

Concepts for Future Aircraft 

2002 [6] Siochi, Anders, Cox, 

Jegley, Fox, Katzberg (116) 

Biomimetics for NASA Langley Research Center: Year 2000 Report of 

Findings From a Six-Month Survey 

2003 [7] Livne (508) Future of Airplane Aeroelasticity 

2003 [8] Livne, Weisshaar (205) Aeroelasticity of Nonconventional Airplane Configurations 

2004 [9] Renton, Olcott, Roeseler, 

Batzer, Baron, Velicki (14) 

Future of Flight Vehicle Structures (2002-2023) 

2009 [2] Weisshaar (35) Aircraft Aeroelastic Design and Analysis – Chapter 1 

2011 [10] Barbarino, Bilgen, Ajaj, 

Friswell, Inman (342) 

A Review of Morphing Aircraft 

(also included later in Table 19) 

2.1 Computational Synthesis Tools 

Synthesis tools for aeroelastic tailoring have been developed to varying degrees of modeling fidelity. The 

literature emphasizes the following four tools as the most utilized: Wing Aeroelastic Synthesis Procedure (TSO), 

Wing Design Optimization with Aeroelastic Constraints (WIDOWAC), Flutter and Strength Optimization Procedure 

(FASTOP), and the Automated Structural Optimization System (ASTROS). ASTROS is still in development, and 

various versions have been utilized over its existence. Table 2 includes summaries of the three tools. 
3

Table 2. Aeroelastic tailoring tools. 

Tool [Ref] Objective Function Constraints Structural Analysis 

TSO [11] “minimum weight skin 

thickness and composite ply 

orientations”* 

“including strength, 

minimum gage, weight, liftcurve, flexible-to-rigid lift 

ratios, deflected shape, and 

flutter and divergence 

speeds”* 

Ritz equivalent plate 

model* 

WIDOWAC [12] Minimum weight Flutter, strength, minimum 

gage constraints 

Finite element based 

FASTOP [13] Minimum weight* Minimum gage, flutter, 

deflection* 

Finite element based 

ASTROS [14] - [16] Modules for finite elements, smart structures, aerodynamics, 

sensitivity analysis, aeroservoelasticity, optimization, 

aeroelastic stability, trim analysis 

Finite element based 

* Ref. [1] 

2.2 Global (Uniform) Tailoring 

Figure 1 (from Ref. [17]) shows that certain aeroelastic tailoring methods can modify the wing’s primary 

stiffness direction, changing the wing’s bending and torsional stiffness as well as the degree of coupling between the 

two. The wing’s primary stiffness direction is defined as the “locus of points where the structure exhibits the most 

resistance to bending deformation,” [17]. The structural reference axis is the “conventional wing structure elastic 

axis,” [17]. If the primary stiffness axis is not coincident with the structural reference axis, the wing will have bendtwist coupling. When the primary stiffness direction is moved forward of the structural reference axis, the bendtwist coupling causes the wing to have more “wash-out” (leading edge down) characteristics. When the primary 

stiffness direction is moved aft of the structural reference axis, the bend-twist coupling causes the wing to have more 

“wash-in” (leading edge up) characteristics [18]. Moving the primary stiffness axis in either direction produces 

desirable changes in wing performance, as labeled in Figure 1, but the two directions clearly involve trade-offs with 

one another. 

Figure 1. The effect that the location of the primary stiffness direction has on the characteristics of the wing 

(adapted from Ref. [17]). 
4

Weisshaar, et al. [17] also discuss how the wing’s sweep and it flexural axis relate to Figure 1, where the 

flexural axis is the “locus of points along the beam where, if a concentrated load were applied there, bending and 

twisting deformation combine to produce no additional angle of attack.” The wing will tend to rotate about its 

flexural axis. With no built-in bend-twist coupling, the location of the flexural axis for a forward swept wing is aft 

of the location of aerodynamic loading, causing natural “wash-in” when the wing is loaded. For the aft swept wing, 

the location of the flexural axis is forward of the location of aerodynamic loading, causing natural “wash-out” when 

the wing is loaded. The location of the flexural axis will vary with the addition of bend-twist coupling. This is 

important in aeroelastic design since, “airloads applied close to this axis will be relatively uncoupled from the 

aerodynamic loads so that aeroelastic interaction is minimal,” [17]. The fundamental work and more detailed 

explanations on this subject are found in Table 3. 

Table 3. Papers covering the fundamental work and further details behind Figure 1. 

Year [Ref] Authors (#Cited works) Title 

1986 [19] Weisshaar, Ryan (9) Control of Aeroelastic Instabilities Through Stiffness Cross-Coupling 

1987 [20] Weisshaar (49) Aeroelastic Tailoring - Creative Uses of Unusual Materials 

1998 [17] Weisshaar, Nam, 

Batista-Rodriguez (38) 

Aeroelastic Tailoring for Improved UAV Performance 

Table 4 includes examples of optimization routines or parametric studies that vary the global (as opposed to the 

local panel level) composite ply orientations or ply sequence on straight or aft swept wings, which is somewhat 

similar to the approach taken on the forward swept wings of the X-29. The last column summarizes the general 

approach of a particular effort. The results were usually positive, although Eastep et al. [21] found that the optimal 

composite structural configurations are fairly insensitive to laminate orientations when imposing various constraints. 

Some papers focused on the challenges of optimizing in a discontinuous design space since small alterations in wing 

design can change the active constraint from flutter to either divergence or another flutter mode. Ghiasi et al. [22] 

provides a review on various approaches used for optimizing the constant stiffness of composite laminates. 

Weisshaar et al. [17] performed parametric studies on a wing (modeled as a beam) in order to reduce induced 

drag and increase the control reversal speed by considering a stiffness cross coupling parameter, wing sweep, wing 

taper, aspect ratio, airspeed, and leading/trailing edge control. Strength, in terms of elastic stress-based failure, was 

not considered. The main findings were as follows: 

• “The amount of stiffness coupling required [to reduce induced drag] is relatively small.” 

• “Aeroelastic tailoring can increase the control reversal speed of swept wings and that different laminate 

designs are needed depending on whether leading edge or trailing edge controls are used.” 

• Considering an Unmanned Air Vehicle (UAV), “Aeroelastic tailoring may not produce a structure with a 

drastically reduced weight compared to an untailored structure. However, the vehicle performance that is 

possible with tailoring may produce the innovative, low-cost design with nearly the same weight but with 

improved performance. However, to be effective, aeroelastic interaction must be large; we may be required 

to operate close to the divergence speed at a given altitude or have noticeable wing flexibility.” 

• “When the aspect ratio is large, tailoring is less effective [with regard to induced drag] and the effects of 

wing distortion on induced drag are more difficult to control.” 

• “Although an elliptically shaped lift distribution creates the least induced drag, when compromising for 

minimum weight (as in aircraft design) the optimal lift distribution becomes more triangular.” 

Table 4. Global aeroelastic tailoring papers that vary the ply orientations of composite wing skins. 

Year [Ref] Authors (#Cited works) Title General approach/emphasis 

1987 [23] Green (14) Aeroelastic Tailoring of Aft-Swept 

High-Aspect-Ratio Composite Wings 

Parametric study 

1989 [24] Isogai (16) Direct Search Method to Aeroelastic 

Tailoring of a Composite Wing under 

Multiple Constraints 

Optimization – 

Discontinuous design space 

(flutter and divergence 

modes) 
5

1999 [25] Visser (16) Aeroelastic and Strength Optimisation 

of a Composite Aircraft Wing Using a 

Multilevel Approach 

Optimization – positive 

outcome 

1999 [21] Eastep, Tischler, 

Venkayya, Khot (10) 

Aeroelastic Tailoring of Composite 

Structures 

Optimization – negative 

outcome 

2002 [26] Qin, Marzocca, Librescu 

(28) 

Aeroelastic Instability and Response of 

Advanced Aircraft Wings at Subsonic 

Flight Speeds 

Parametric study – a focus 

on warping restraint 

2004 [27] Hirano, Todoroki (23) Stacking Sequence Optimizations for 

Composite Laminates Using Fractal 

Branch and Bound Method: 

Application for Supersonic Panel 

Flutter Problem with Buckling Load 

Condition 

Optimization – positive 

outcome 

2005 [28] Kim, Hwang (17) Optimal Design of Composite Wing 

Subjected to Gust Loads 

Optimization – positive 

outcome 

2006 [29] Seresta, Abdalla, Mulani, 

Marzocca (33) 

Stacking Sequence Design of Flat 

Composite Panel for Flutter and 

Thermal Buckling 

Optimization – positive 

outcome 

2007 [30] Kim, Oh, Kweon, Choi 

(5) 

Weight Optimization of Composite Flat 

and Curved Wings Satisfying Both 

Flutter and Divergence Constraints 

Optimization – positive 

outcome 

2007 [31] Kameyama, Fukunaga 

(19) 

Optimum Design of Composite Plate 

Wings For Aeroelastic Characteristics 

Using Lamination Parameters 

Optimization – 

discontinuous design space 

(flutter and divergence 

modes) 

2008 [32] Manan, Cooper (44) Uncertainty of Composite Wing 

Aeroelastic Behaviour 

Optimization – positive 

outcome 

2009 [33] Harmin, Cooper (19) Aeroelastic Tailoring Using Ant 

Colony Optimization 

Optimization – positive 

outcome 

2009 [22] Ghiasi, Pasini, Lessard 

(139) 

Optimum Stacking Sequence Design of 

Composite Materials, Part 1: Constant 

Stiffness Design 

A review of optimization 

routines used for 

determining constant 

stiffness designs of 

composite laminates 

2011 [34] Attaran, Majid, Basri, 

Mohd Rafie, Abdullah (18) 

Structural Optimization of an 

Aeroelastically Tailored Composite 

Flat Plate Made of Woven 

Fiberglass/Epoxy 

Parametric study 

2.3 Local (Non-uniform Tailoring) 

When separate sections of the wing are tailored differently from one another, aeroelastic tailoring is applied in a 

more “local” manner over the wing. The following four tables list references that pertain to this less common, local 

approach to aeroelastic tailoring. Certain local approaches to wing structural design are not included here but in a 

later section, since they did not explicitly account for aerodynamic interactions. Table 5 covers papers that vary ply 

orientations of separate composite laminate panels (as opposed to one “global” panel) making up the wing’s skin. 

Table 6 provides papers that utilize non-conventional structural topologies. By comparing the topologies among 

these designs, general insights into the best arrangement of structure and stiffness may be possible. Table 7 

considers the employment of various aeroelastic tailoring techniques into a single study or optimization routine. In 

particular, De Leon et al. [35] studies extremely localized aeroelastic tailoring by orienting composite fibers at the 

elemental level. Finally, Table 8 covers papers that utilize highly idealized wing models, such as simple 1D beams 

where the optimal thickness of each beam section is determined. 
6

Table 5. Aeroelastic tailoring papers using varying ply orientations amongst separate composite panels. 

Year [Ref] Authors 

(#Cited works) 

Title Summary 

2006 [36] Guo, 

Cheng, Cui 

(17) 

Aeroelastic 

Tailoring of 

Composite 

Wing 

Structures by 

Laminate 

Layup 

Optimization 

• Conducted a parametric study on a wing box comprised of 20 

different panels. Varied the wing planform and also optimized the 

laminate fiber orientations over each panel. 

• The weight of each wing box was constant. 

• Utilized gradient and discrete optimization methods to optimize for 

maximum flutter speed. 

• The results are summarized in Figure 3 (of the paper). The quasiisotropic laminate [0/-45/45/90]° had the worst results. Maximum 

torsional rigidity [-45/45]° showed much improvement. Best 

results came from optimizing each panel individually. Optimized 

designs are summarized by their calculated EI (bending stiffness), 

GJ (torsional stiffness), and CK (coupling rigidity). When 

performing aeroelastic tailoring, it is more effective to optimize CK 

for straight wings and GJ for swept wings. 

• Did not consider structural strength or skin buckling. 

2007 [37] Guo (26) Aeroelastic 

optimization of 

an aerobatic 

aircraft wing 

structure 

• Performed optimization on a wing comprised of 24 panels (6 

spanwise by 4 circumferentially). Each panel had 8 plies. 

• Results show that wings with the highest flutter speed have 

increased torsional rigidity (GJ) and decreased bending rigidity 

(EI). This would separate the uncoupled bending and torsional 

frequencies, increasing the flutter speed at which they coalesce. 

Wings with highest flutter speed also had some bend-twist coupling 

(CK). 

• The results indicate that the optimization routines did not reach 

global optimums (for example, the design space of case 1 included 

the design space of case 2, yet the final result of case 2 was better 

than case 1), thus nothing can be concluded here about the benefits 

or shortcomings of varying fiber angles per spanwise wing section. 

2007 [38] Herencia, 

Weaver, 

Friswell (51) 

Morphing 

Wing Design 

via Aeroelastic 

Tailoring 

• Optimized a composite wing box having 5 segments from root to 

tip. Each skin and spar panel was optimized for ply sequence 

(flexural anisotropy) and ply volume fraction (membrane 

anisotropy) using only 0°, +45°, -45° and 90° ply orientation 

permutations. 

• Optimized first for only structural constraints (strength, buckling, 

practical design, etc.). Optimized second for both structural and 

aerodynamic (lift and drag) constraints. 

• In areas of higher buckling, there was less use of anisotropy. When 

more anisotropy was used, the wing panels were typically thicker. 

Consequently, drag was able to be reduced by 1.4% but weight was 

increased by 18.7%. 
7

2010 [39] Chang, 

Yang, Wang, 

Wang (32) 

Design 

Optimization 

of Composite 

Wing Box for 

Flutter and 

Stiffness 

• Optimized three composite wing boxes each having 5 segments 

from root to tip. One wing box was constrained to have uniform 

thickness across the 5 segments. Three studies were performed on 

each wing box to determine optimum fiber orientations. 

• The weight of each wing box was constant. 

• Utilized a genetic algorithm to optimize for maximum flutter speed 

and minimum tip deflection simultaneously. 

• Designs with the maximum flutter also had the most tip deflection. 

• Comparisons cannot be made between the 1st study and the other 

two studies since the thickness per ply was not constant. 

Comparing the results of the 2nd and 3rd study suggest that 

optimizing the fiber orientation per panel, verses keeping it uniform 

across the panels, increases flutter speed. 

• The wing box of uniform thickness had highest flutter speeds, and 

its panels closer to the root had greater impact on flutter. For the 

nonuniform thickness wing boxes, the panels furthest from the root 

had greater impact on flutter. 

• Did not consider strength or skin buckling. Plans for more studies 

using additional load cases and objectives. 

Table 6. Aeroelastic tailoring papers using isotropic materials and structural design optimization. 

Year [Ref] Authors 

(#Cited works) 

Title Summary 

1975 [40] Haftka (10) Parametric 

Constraints 

with 

Application to 

Optimization 

for Flutter 

Using a 

Continuous 

Flutter 

Constraint 

• Used WIDOWAC to compute the optimal thickness distribution of 

a low aspect ratio titanium wing with a beryllium patch. 

• Wing mass was minimized subject to a flutter constraint 

• Results indicate that, due to the discontinuous nature of the 

aeroelastic flutter mechanism (i.e., the advent of hump modes, or 

the loss of criticality of a conventional flutter mechanism), an 

equivalent nonparametric “minimum value” constraint is preferred 

to a conventional flutter-based parametric constraint. 

2002 [41] Stroud, 

Krishnamurthy, 

Mason, Smith, 

Naser (11) 

Probabilistic 

Design of a 

Plate-Like 

Wing to Meet 

Flutter and 

Strength 

Requirements 

• Developed a reliability-based design approach to aeroelastic 

tailoring of a metallic plate-like wing. 

• Minimized weight by varying the wing thickness distribution using 

nine locations on the wing. 

• Determined that reliability can be increased with relatively small 

increases in weight. 

• Figures 7 and 12 (in the paper) show two designs with similar 

weight but different load paths. The thickest regions are the leading 

edge at midspan and the root. The thinnest regions are the rear 

trailing edge, the tip, and the very forward root area. 

• Considered strength and flutter. 

2004 [42] Martins, 

Alonso, Reuther 

(23) 

High-Fidelity 

Aerostructural 

Design 

Optimization 

of a 

Supersonic 

Business Jet 

• Reduced weight on a natural-laminar flow supersonic business jet 

by employing multidisciplinary design optimization. 

• Minimized weight and drag simultaneously by optimizing the 

OML and spar/rib thicknesses and depths. 

• The surface density distribution of the optimized wing in Figure 12 

(of the paper) shows more material toward the leading edge at both 

the midspan and tip. 

• Considered strength and aeroelasticity. Utilized previously 

developed analysis tools. Did not consider flutter and skin 

buckling. 
8

2004 [43] Maute, 

Allen (61) 

Conceptual 

Design of 

Aeroelastic 

Structures by 

Topology 

Optimization 

• Performed two examples of topology optimization. 

• The first example showed that fluid-structure interaction cannot be 

overlooked when performing aeroelastic tailoring. When including 

this interaction, drag was reduced and the topology showed one 

thick spar that terminated at the leading edge where additional 

material was also located. 

• The second example minimized mass by identifying areas in the 

spars and ribs that can be less stiff. The results showed that ribs 

were stiffer toward the outboard of the wing and the spars were 

stiffer toward the inboard of the wing. The ribs had the greatest 

stiffness at the leading edge and underside of the wing, where the 

pressures are greater. 

• Considered stress and aerodynamics. Did not account for flutter 

nor buckling of skin and stiffeners. 

2005 [44] Okada, 

Furuya (21) 

Robust 

Structural 

Optimization 

of Plate Wing 

Corresponding 

to Bifurcation 

in Higher 

Mode Flutter 

• Developed robust structural design optimization of a constant 

mass, varying thickness plate-like delta wing to maximize the 

critical dynamic speed associated with supersonic flutter. 

• Increased the flutter speed by 6 times. 

• Improved convergence by constraining adjacent modes to be a 

constant distance apart from one another. 

• Future work will consider the effects of damping. Did not consider 

strength. 

2008 [45] Gomes, 

Suleman (27) 

Topology 

Optimization 

of a 

Reinforced 

Wing Box for 

Enhanced Roll 

Maneuvers 

• Developed a level-set method to reinforce the upper skin of a wing 

torsion box for increased aileron reversal dynamic pressure. 

• Optimized the thickness variation over the upper surface. 

• Utilized COBYLA, a derivative-free optimization tool. 

• Despite different initial designs, the optimizer always led to 

material reinforcement at the leading and trailing edges. 

• Considered only torsional loads to simulate aerodynamic loads. 

Did not consider stress, skin buckling, and flutter constraints. 

2009 [46] Kobayashi, 

Pedro, Kolonay, 

Reich (27) 

On a Cellular 

Division 

Method for 

Aircraft 

Structural 

Design 

• Developed a biologically inspired topology optimization method 

that breaks a wing structure into “cells”. 

• Utilized a wing box model of a generic fighter aircraft and varied 

the topology variables, thicknesses, and stiffnesses via a genetic 

algorithm. 

• Displayed results by using a Pareto set between mass and stress. 

With additional mass available, more stiffeners were added in the 

optimization verses adding more structural thickness. 

• Utilized the doublet lattice method. Did not indicate flutter as a 

constraint. Did not consider skin buckling. 

2011 [47] Stanford, 

Beran (23) 

Optimal 

Structural 

Topology of a 

Plate-Like 

Wing for 

Subsonic 

Aeroelastic 

Stability 

• Studied the Pareto front between mass and aeroelastic instability 

using an aluminum plate of different planforms. 

• Varied the thickness of each element. 

• Experienced slower convergence due to switching between 

resultant flutter and divergence modes while using a gradient based 

optimizer. 

• The optimized variable thickness wing was always better than the 

uniform-thickness wing. 

• The straight and aft-swept wings had some similarities, including 

the following: most of the mass was towards the leading edge, 

lower mass designs have rib-like distributions of mass, and the 

mass at the root is focused at the leading and trailing edges. 

• Considered flutter but did not include strength as a constraint. 
9

2011 [48] Harmin, 

Ahmed, 

Cooper, Bron 

(13) 

Aeroelastic 

Tailoring of 

Metallic Wing 

Structures 

• Varied the unidirectional orientation of the ribs and skin 

crenulations (ridges) in both rectangular and tapered wing boxes to 

assess their effects on flutter speed and bending and twist 

deflection. 

• The structural weight was constrained as a constant. 

• Demonstrated bending and torsion coupling and also increased 

flutter speed by 3%. 

• Did not consider stress, skin buckling, or the variation of 

orientations between adjacent ribs or crenulations. 

2012 [49] Stanford, 

Beran (39) 

Computational 

Strategies for 

ReliabilityBased 

Structural 

Optimization 

of Aeroelastic 

Limit Cycle 

Oscillations 

• Optimized the thickness distribution of a cantilevered plate in 

supersonic flow for minimum mass. 

• Used a constraint on the nonlinear post-flutter limit cycle 

oscillation amplitude, rather than the flutter point itself. 

• Considered both deterministic LCO constraints, as well as 

probabilistic (i.e., the probability that an LCO amplitude will be 

larger than required). 

• Utilized proper orthogonal decomposition (POD)-based model 

reduction and time-periodic spectral elements to reduce LCO 

optimization cost. 

• Low-mass plates with feasible LCO amplitudes were found by 

lumping mass along the leading edge of the wing. A very minor 

increase in the leading edge material could drop the probability of 

LCO failure substantially. 

2012 [50] 

Sleesongsom, 

Bureerat (33) 

New 

Conceptual 

Design of 

Aeroelastic 

Wing 

Structures by 

MultiObjective 

Optimization 

• Used structural sizing and topology variables to solve multiobjective aeroelastic optimization problems for wing weight, 

buckling, and lift effectiveness. 

• Considered constraints on divergence, flutter, and stress metrics. 

• Topological variables based on a ground structure approach, and 

was found to give superior designs to those with just conventional 

sizing variables, via a multi-objective population-based 

incremental learning algorithm. 

2013 [51] Dunning, 

Brampton, Kim 

(20) 

Multidisciplinary Level Set 

Topology 

Optimization 

of the Internal 

Structure of an 

Aircraft Wing 

• Used level set methods to find the optimal internal distribution of 

material within a rectangular aeroelastic wing box. 

• Element mesh composed of tri-linear finite elements, which could 

appear or disappear during the optimization: design problem was to 

minimize compliance subject to a weight and a lift constraint. 

• Optimal topology was not found to have rib and spar-like patterns 

(instead large sections of mass were lumped along the root and/or 

tip), though results are preliminary. 
10

Table 7. Aeroelastic tailoring papers using tailoring techniques that are not specific to a single category. 

Year [Ref] Authors 

(#Cited works) 

Title Summary 

1991 [52] Bohlmann, 

Scott (8) 

A Taguchi 

Study of the 

Aeroelastic 

Tailoring 

Design 

Process 

• Implemented a Taguchi Method to determine important design 

components to consider when aeroelastically tailoring a generic F-16 

wing model. 

• Considered laminate orientation, ply thickness, built in camber, 

control surface deflections, and others. 

• Evaluations included weight, roll rate effectiveness, hinge moment 

effectiveness, roll damping flex-to-rigid ratio, and others. Utilized 

TSO (tool) for determining strength, flutter, and roll moment 

effectiveness. 

• One conclusion states that when the laminate orientations are not 

constrained, the structural weight increases. For example, the bidirectional laminate [-45/45]° which had the best torsional rigidity 

required additional plies to compensate for its low bending rigidity. 

• Provides design guidelines but the study is “not all encompassing.” 

1992 [53] Rehfield, 

Chang, Zischka 

(12) 

Modeling And 

Analysis 

Methodology 

For 

Aeroelastically 

Tailored 

Chordwise 

Deformable 

Wings 

• Introduced enhanced-lift design concepts that elastically increase 

camber when bent or twisted. “Elastically produced camber is 

created by establishing a differential chordwise membrane strain 

between the upper and lower box covers while preserving the 

structural box.” 

• In the bending example of a generic transport wing, the 

‘Exaggerated Poisson’s Effect’ is produced by both composites and 

the orientation of unidirectional stiffeners. 

• Performed an experiment on a wing box to validate the analysis 

methodology for the bending-camber concept. 

• Considers stress, skin buckling, and divergence. Did not account for 

flutter. 

• Appendix D (in the paper) provides rib concepts for the proposed 

designs. 

2005 [54] Arizono, 

Isogai (14) 

Application of 

Genetic 

Algorithm for 

Aeroelastic 

Tailoring of a 

CrankedArrow Wing 

• Developed a genetic algorithm to optimize the laminate orientation 

and the spar, rib, and skin thicknesses of a cranked-arrow wing of a 

supersonic jet for minimum structural weight. 

• To minimize the number of design variables, the wing was 

subdivided into regions of uniform structural thicknesses. 

• The inclusion of laminate orientations provided additional weight 

reduction. 

• Considered strength, local buckling, and flutter constraints. 

2012 [55] Kennedy, 

Martins (32) 

A Comparison 

of Metallic and 

Composite 

Aircraft Wings 

using 

Aerostructural 

Design 

Optimization 

• Multidisciplinary design optimization of a high aspect ratio subsonic 

transport wing box, using either metallic structures or composite 

structures. 

• Obtained the Pareto front between fuel burn and gross take-off 

weight via wing shape and wing structure variables, under trim 

constraints, strength constraints, and skin buckling constraints, but 

did not consider flutter. 

• Extra design freedom afforded by orthotropic composites was found 

to provide sizeable improvements in aspect ratio, weight, and fuel 

burn. 
11

2012 [35] De Leon, 

de Souza, 

Fonseca, da 

Silva (42) 

Aeroelastic 

Tailoring 

Using Fiber 

Orientation 

and Topology 

Optimization 

• Optimized laminated flat plate designs by first optimizing elemental 

fiber orientations for increased flutter speed and then by optimizing 

the elemental material density for minimum weight. 

• Developed a procedure to exploit tow steering fabrication. 

• Increased the flutter speed by maximizing the eigenvalue associated 

with the eigenmode involved with the flutter onset. 

• Tools included ZAERO (including ZONA 6 unsteady lifting surface 

method). 

• Did not consider strength. 

2013 [56] Dillinger, 

Klimmek, 

Abdalla, 

Gürdal (32) 

Stiffness 

Optimization 

of Composite 

Wings with 

Aeroelastic 

Constraints 

• Optimized stacking sequence of wing skins for either mass or aileron 

effectiveness, with constraints on laminate failure and buckling. 

• Gradient based optimization via response surface methods, with the 

elements of the in-plane and the bending stiffness matrices used 

directly as design variables. 

• Unbalanced laminates showed superior performance over balanced 

for all optimization problems. 

Table 8. Aeroelastic tailoring papers having simplified, highly idealized wing models, typically comprised of 

1D beam elements. 

Year [Ref] Authors (#Cited works) Title 

1982 [57] Seyranian (42) Sensitivity Analysis and Optimization of Aeroelastic Stability 

1988 [58] Craig, McLean (8) Spanload Optimization for Strength Designed Lifting Surfaces 

1996 [59] Butler, Banerjee (13) Optimum Design of Bending-Torsion Coupled Beams with Frequency or 

Aeroelastic Constraints 

1999 [60] Barboni, Mannini, 

Gaudenzi (11) 

On the Use of the P-TFE Method for Panel Flutter Optimization 

1999 [61] Langthjem, Sugiyama 

(21) 

Optimum Shape Design Against Flutter of a Cantilevered Column With 

an End-Mass of Finite Size Subjected to a Non-Conservative Load 

2004 [62] Lemanski, Weaver (5) Flap-Torsion Coupling in Prismatic Sections 

2006 [63] Palaniappan, Beran, 

Jameson (9) 

Optimal Control of LCOs in Aero-Structural Systems 

2007 [64] Pastilha (45) Structural Optimization for Flutter Instability Problems 

2013 [65] Stanford, Beran (37) Direct Flutter and Limit Cycle Computations of Highly-Flexible Wings 

for Efficient Analysis and Optimization 

2.4 Additional Tailoring Approaches 

This section covers a variety of research papers that are relevant to aeroelastic tailoring but are not directly 

applicable to either global or local tailoring or the goal of weight reduction in transport aircraft. Table 9 includes 

research papers on the accurate weight calculation of aircraft. Table 10 provides research papers on the aeroelastic 

tailoring of micro air vehicles. Table 11 includes additional papers concerning aeroelastic tailoring that have 

insightful conclusions that are important to consider during wing design. Finally, Table 12 covers papers that are 

relevant to modeling, analysis, and optimization of aeroelastically tailored structures. 

Table 9. Research on accurate weight calculation of aircraft. 

Year [Ref] Authors (#Cited 

works) 

Title 

2000 [66] Boynton, Weiner (3) Measuring Mass Properties of Aircraft Control Surfaces 

2004 [67] Regis, de Mattos (28) Wing Structural Weight Evolution With The Cruise Mach Number Of A 

Commercial Transport Aircraft 
12

Table 10. Aeroelastic tailoring of micro air vehicles. 

Year [Ref] Authors (#Cited 

works) 

Title 

2008 [68] Stanford, Ifju (148) Fixed Membrane Wings for Micro Air Vehicles: Experimental 

Characterization, Numerical Modeling, and Tailoring 

2009 [69] Stanford, Ifju (34) Aeroelastic Topology Optimization of Membrane Structures for Micro Air 

Vehicles 

2009 [70] Stanford, Ifju (27) Multi-Objective Topology Optimization of Wing Skeletons for Aeroelastic 

Membrane Structures 

Table 11. Relevant outcomes of aeroelastic tailoring work. 

Year [Ref] Authors 

(#Cited works) 

Title Summary 

2001 [71] Inglesias, 

Mason (18) 

Optimum Spanloads 

Incorporating Wing 

Structural Weight 

Concluded that when minimizing weight, optimizing the 

spanloads to reduce root bending moment is more 

effective than optimizing spanloads for reduced drag. 

2003 [72] Pettit, 

Grandhi (20) 

Optimization of a Wing 

Structure for Gust 

Response and Aileron 

Effectiveness 

Optimized for weight reduction with gust response and 

aileron effectiveness constraints. Future work will 

include stress and flutter considerations. “[A result] 

indicates that the structure’s aeroelastic properties are 

much more sensitive to Young’s modulus variability in 

the skin panels than to variability in their thickness or 

spar and rib thickness.” 

2004 [73] Papila, 

Haftka, Mason, 

Alves (12) 

Tailoring Wing Structures 

for Reduced Drag Penalty 

in Off-Design Flight 

Conditions 

Optimized a wing for reduced drag and had better results 

when considering off-design flight conditions instead of 

a single flight condition. 

2005 [74] Love, Zink, 

Wieselmann, 

Youngren (8) 

Body Freedom Flutter of 

High Aspect Ratio 

FlyingWings 

Did not have success with aeroelastically tailoring a 

flying wing aircraft to delay body freedom flutter, 

although it is mentioned that too many simplifications 

may have been made, including not accounting for 

weight addition when adding stiffness. Promotes active 

aeroelastic tailoring. 

2012 [75] Wang, Liu, 

Tang, Yang (15) 

The Influence of Spar 

Position on Aeroelastic 

Optimization of a Large 

Aircraft Wing 

Found that the position of the leading edge spar had a far 

greater impact on the aeroelastic optimization process 

than the trailing edge spar. Results indicated better 

designs with composite wings, as compared to metallic, 

but the optimal wing weight of both increased 

substantially if design constraints were difficult to 

satisfy. 

Table 12. Modeling, analysis, and optimization approaches for aeroelastic tailoring. 

Year [Ref] Authors 

(#Cited works) 

Title Emphasis 

1989 [76] Livne (6) An Integrated Approach To The Optimum Design Of Actively 

Controlled Composite Wings 

Multidisciplinary 

design, analysis, 

and optimization 

(MDAO) 

1998 [77] Komarov, 

Weisshaar (18) 

Aircraft Structural Design - Improving Conceptual Design Level 

Fidelity 

MDAO 

1998 [78] Blair, Hill, 

Weisshaar (10) 

Rapid Modeling with Innovative Structural Concepts Model – (includes 

organic wing 

design) 
13

1999 [79] Livne, 

Navarro (24) 

Nonlinear Equivalent Plate Modeling of Wing Box Structures Model 

1999 [80] Reuther, 

Alonso, Martins, 

Smith (28) 

A Coupled Aero-Structural Optimisation Method for Complete 

Aircraft Configurations 

MDAO 

2001 [81] Gumbert, 

Hou, Newman 

(42) 

Simultaneous Aerodynamic and Structural Design Optimization 

(SASDO) for a 3-D Wing 

MDAO 

2009 [82] Demasi, 

Livne (65) 

Dynamic Aeroelasticity of Structurally Nonlinear Configurations 

Using Linear Modally Reduced Aerodynamic Generalized Forces 

Analysis 

2010 [83] Yoon (46) Topology Optimization for Stationary Fluid-Structure Interaction 

Problems using a New Monolithic Formulation 

MDAO 

2010 [84] Fazelzadeh, 

Marzocca, 

Mazidi, Rashidi 

(19) 

Divergence and Flutter of Shear Deformable Aircraft Swept 

Wings Subjected to Roll Angular Velocity 

Analytical model 

2011 [85] Seeger, 

Wolf (27) 

Multi-Objective Design of Complex Aircraft Structures Using 

Evolutionary Algorithms 

MDAO 

2012 [86] Bhatia, 

Kapania, Haftka 

(17) 

Structural and Aeroelastic Characteristics of Truss-Braced 

Wings: A Parametric Study 

MDAO 

2012 [87] Daoud, 

Petersson, 

Deinert, Bronny 

(12) 

Multidisciplinary Airframe Design Process: Incorporation of 

Steady and Unsteady Aeroelastic Loads 

MDAO 

3 Potential Enabling Technologies of Aeroelastic Tailoring 

This section highlights technologies that can directly affect a wing’s stiffness, mass, or aerodynamics, although 

not all papers below explicitly account for aerodynamic loading. If a technology does not require controls for 

aeroelastic tailoring purposes, it is considered ‘passive’. Otherwise, the technology is considered ‘active’. The 

following sections are broken down by this active/passive distinction. 

3.1 Passive 

Various developments in materials and structures may contribute to the aeroelastic tailoring of wings for further 

weight reduction and improved performance. This section introduces various potential enabling technologies, 

including: selectively reinforced materials, functionally graded materials, fiber tow steered composite laminates, and 

various nonconventional structural designs. 

3.1.1 Selectively Reinforced Materials 

Selectively reinforced materials are a particular type of composite material. One example is metal matrix 

composites (MMCs), which are metals or alloys that are reinforced by another material. Porous metals, also called 

metal foams or microcellular metals, are also included within this category [88]. MMCs have been applied to 

various aeronautic vehicles, including the ventral fin of the F-16 [89]. These composites take advantage of the best 

properties of their individual constituents, but their usage is limited due to their relatively high manufacturing cost 

[90]. Table 13 and Table 14 list brief summaries of papers relevant to either MMCs in general or their application in 

aerospace. There is no record of MMCs being used specifically for the aeroelastic tailoring of wings. 

A subset of MMCs is fiber metal laminates (FMLs). A common example is GLARE, a “Glass Laminate 

Aluminium Reinforced Epoxy”, which is comprised of layers of glass fiber that are interspersed and bonded 

between layers of metal [91]. Like MMCs, the composite laminates have attractive properties, but are relatively 

expensive. However, GLARE is currently used in the upper fuselage skin of the A380 [92]. Table 15 and Table 16 

list brief summaries of papers relevant to either GLARE or its integration into aerospace applications.

Finally, Reinforced Core Sandwich (RCS) and Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) 

panels are two specific examples of lightweight, reinforced constructions of materials. Bednarcyk et al. [93] 

developed and verified a tool to incorporate and size RCS and PRSEUS panels for lightweight designs. They 

describe the two reinforcement methods as follows:
14

• “Reinforced core sandwich (RCS) panels combine aspects of foam core sandwich panels and stiffened 

panels in a concept that includes integral composite webs for optimum through thickness shear capabilities 

and excellent damage tolerance.” 

• “Boeing’s Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels rely on pre-cured 

unidirectional composite rods for high axial stiffness, integral foam core frames of transverse support, and 

stitching for superior damage tolerance.” 

Table 13. Papers on the state-of-the-art and aeronautical applications of MMCs. 

Year [Ref] Authors 

(#Cited works) 

Title Overview 

1991 [94] Ibrahim, 

Mohamed, 

Lavernia (127) 

Particulate 

Reinforced Metal 

Matrix Composites - 

a Review 

Describes the state-of-the-art of particulate reinforced MMCs as 

of 1991. Provides historic examples of weight savings. 

Presents physical and material properties. 

1997 [95] Degischer 

(20) 

Innovative Light 

Metals: Metal 

Matrix Composites 

and Foamed 

Aluminum 

Describes particulate reinforced light metals, continuous fiber 

reinforced light materials, and aluminum foam. 

2001 [89] Miracle 

(1) 

Aeronautical 

Applications for 

Metal Matrix 

Composites 

Describes aeronautical applications of MMCs, including the use 

in the ventral fin on the F-16. The MMC design had a 40% 

increase in specific stiffness and reduced the tip deflection by 

50%. 

2005 [90] Miracle 

(47) 

Metal Matrix 

Composites – From 

Science to 

Technological 

Significance 

Describes the state-of-the-art of MMCs as of 2005. States that 

many of the technical challenges of MMCs have been overcome 

or minimized, although their cost is still relatively high. Figure 1 

(in the paper) compares the stiffness vs. strength properties of 

metals and MMCs. Provides examples of applications of 

MMCs, including selective reinforcement of an engine block. 

Explains that MMC’s can be functionally graded. 

2010 [88] 

Mortensen, 

Llorca (140) 

Metal Matrix 

Composites (Annual 

Review) 

Describes the state-of-the-art as of 2010. Provides a thorough 

introduction of MMCs and their benefits. Describes newly 

developed MMC materials and the research focused on 

understanding the physics and micromechanics of these 

materials. Microcellular metals (metal foams) have seen a recent 

thrust in research. 

Table 14. Recent but less relevant papers on MMCs. 

Year [Ref] Authors (#Cited works) Title Emphasis 

2000 [96] Kaczmar, Pietrzak, Wlosinski 

(68) 

The Production and Application of Metal 

Matrix Composite Materials 

Overview on 

MMCs 

2001 [97] Rawal (10) Metal-Matrix Composites for Space 

Applications 

Space applications 

of MMCs 

2009 [98] Fernández, González-Doncel 

(38) 

Additivity of Reinforcing Mechanisms 

During Creep of Metal Matrix Composites: 

Role of the Microstructure and the 

Processing Route 

Creep in MMCs 

2009 [99] Scherm, Völkl, van Smaalen, 

Mondal, Plamondon, L’Espérance, 

Bechmann, Glatzel (20) 

Microstructural Characterization of 

Interpenetrating Light Weight Metal 

Matrix Composites 

MMCs at the 

microstructural 

level 

2012 [100] Ricks, Lacy, Bednarcyk, 

Arnold (14) 

A Multiscale Modeling Methodology for 

Metal Matrix Composites Including Fiber 

Strength Stochastics 

Modeling MMCs 
15

Table 15. Papers on the state-of-the-art and aeronautical applications of GLARE. 

Year [Ref] Authors 

(#Cited works) 

Title Overview 

2007 [101] Slingerland, 

Alkemadey, 

Vermeulenz (11) 

A Preliminary 

Prediction 

Method for the 

Effect of New 

Fuselage 

Materials on 

Transport 

Aircraft Weight 

Developed a method for predicting aircraft weight when 

fuselage materials are either metals or fiber metal laminates like 

GLARE. Describes the composition and material properties of 

GLARE. Conclusion provides estimated aircraft weight savings 

when using GLARE. 

2008 [92] Alderliesten, 

Benedictus (46) 

Fiber/Metal 

Composite 

Technology for 

Future Primary 

Aircraft 

Structures 

Describes the state-of-the-art as of 2008. States that GLARE is 

tailorable. Emphasizes that damage tolerance must be 

considered when making aircraft weight assessments between 

materials. Provides a good description of the benefits of 

combining the two materials: “Metals have a high bearing 

strength and impact resistance and are easy to repair, whereas 

full composites have excellent fatigue characteristics and high 

strength and stiffness.” 

Table 16. Additional papers on GLARE. 

Year [Ref] Authors 

(#Cited works) 

Title Emphasis 

2003 [102] Schmidt, 

Schmidt-Brandecker 

(4) 

Damage Tolerant Design And Analysis Of Current 

And Future Aircraft Structure 

Damage requirements, 

GLARE vs. aluminum 

comparison 

2010 [103] Seo, Hundley, 

Hahn, Yang (17) 

Numerical Simulation of Glass-Fiber-Reinforced 

Aluminum Laminates with Diverse Impact 

Damage 

Damage considerations, 

modeling GLARE 

3.1.2 Functionally Graded Materials 

Functionally graded metals are especially beneficial to high temperature applications like supersonics since they 

eliminate discrete changes in the coefficient of thermal expansion which can cause significant stress at the boundary 

between two adjacent materials [104]. Marzocca, et al. provides a literature survey on nonlinear aero-thermalelasticity of functionally graded panels. The survey’s relevance is limited though since the extent of functional 

grading is modeled by a simple volume fraction parameter. Also, the benefits did not cover subsonic transports or 

detailed wing designs [104]. 

A paper by Venkataraman and Sankar [105] demonstrates the benefits of reinforcing a hole with continuously 

graded material. New manufacturing processes, such as the electron beam freeform fabrication (EBF3

) [106], are 

helping to enable the fabrication of functionally graded metals. Pettit and Grandhi [72] concluded that a wing 

“structure’s aeroelastic properties are much more sensitive to Young’s modulus variability in the skin panels than to 

variability in their thickness or spar and rib thickness.” For this reason, the grading of the Young’s modulus may be 

very effective in aeroelastic tailoring efforts, at least for the configuration considered in [72]. 

3.1.3 Fiber Tow Steering 

Fiber tow steering is a fabrication process that enables fibers of a composite laminate to be applied along 

curvilinear paths within a single ply. This adds increased design freedom in composite laminate design. The 

earliest work referenced on fiber tow steering was in 1972 [107]. Advanced Fiber Placement (AFP) is a larger 

category of manufacturing processes that includes fiber tow steering. Kisch states [108] that the A380 and 787 

fuselages are both fabricated using AFP. Although not specifically stated, it is likely that AFP has been employed 

for its efficiency in fabricating large composite laminate structures and less for its ability to exploit intricate fiber 

orientations via fiber tow steering. 

Many research efforts have involved improving the strength or buckling resistance of plates or plates with cutouts. It has been shown that a simple “S” shaped fiber path (one that aligns axially, curves to 45°, and then realigns 
16

axially again) improves the buckling resistance of axially loaded plates by “shifting the load away from the 

unsupported center,” [109]. With additional buckling resistance in skin panels, fewer stiffeners may be needed. 

When designing for fiber tow steering, practical constraints like the fiber tow turning radius must be met. The 

papers chosen for Table 17 are recent and cover a broad group of topics relevant to fiber tow steering, including 

manufacturing processes and applications. In particular, Ghiasi, et al. [110] provides a review of “variable stiffness 

design” in composite laminates, which includes to the use of curvilinear fiber paths. It also discusses methods for 

determining optimal fiber paths based on principle stresses or load paths. The paper by De Leon, et al. [35] 

discussed above obtains the fiber angle of each finite element, which may also be considered a type of tow steering. 

The last two papers in the table consider aeroelastic metrics, with Ref. [111] in particular considering flutter-based 

optimization of a tow-steered thin walled beam. 

Table 17. Papers on fiber tow steering. 

Year [Ref] Authors 

(#Cited works) 

Title Emphasis 

2006 [108] Kisch (10) Automated Fiber Placement Historical 

Perspective 

Manufacturing processes and 

applications 

2010 [112] Ijsselmuiden, 

Abdalla, Gürdal (33) 

Optimization of Variable-Stiffness Panels 

for Maximum Buckling Load Using 

Lamination Parameters 

State-of-the-art on methods used to 

parameterize and optimize fiber 

path orientations 

2009 [113] Weaver, 

Potter, Hazra, 

Saverymuthapulle, 

Hawthorne (30) 

Buckling of Variable Angle Tow Plates: 

From Concept to Experiment 

Optimizing for buckling resistance 

2010 [114] Alhajahmad, 

Abdalla, Gürdal (16) 

Optimal Design of Tow-Placed Fuselage 

Panels for Maximum Strength with 

Buckling Considerations 

Optimizing for strength and 

buckling resistance 

2009 [109] Butler, Baker, 

Liu (10) 

Damage Tolerance of Buckling Optimized 

Variable Angle Tow Panels 

Optimizing for maximum buckling 

resistance and analyzing for 

damage tolerance 

2009 [115] Honda, Narita, 

Sasaki (20) 

Maximizing the Fundamental Frequency of 

Laminated Composite Plates with 

Optimally Shaped Curvilinear Fibers 

Optimizing for desired frequency 

2005 [116] Tatting, 

Setoodeh, Gürdal 

(8) 

Enhancements of Tow-Steering Design 

Techniques: Design of Rectangular Panel 

Under Combined Loads 

Optimizing a panel for combined 

loads (axial and shear) 

2010 [110] Ghiasi, 

Fayazbakhsh, 

Pasini, Lessard 

(118) 

Optimum Stacking Sequence Design of 

Composite Materials, Part II: Variable 

Stiffness Design 

A review paper on variable 

stiffness designs using curvilinear 

fiber paths in composite laminates 

2010 [117] Lopes, 

Gürdal, Camanho 

(23) 

Tailoring for Strength of Composite 

Steered-Fibre Panels with Cutouts 

Optimizing a panel with a cutout 

2011 [118] Croft, 

Lessard, Pasini, 

Hojjati, Chen, 

Yousefpour (26) 

Experimental Study of the Effect of 

Automated Fiber Placement Induced 

Defects on Performance of Composite 

Laminates 

Manufacturing defects pertaining 

to tow steering and their effect on 

structural performance 

2012 [119] Kim, Potter, 

Weaver (20) 

Continuous Tow Shearing For 

Manufacturing Variable Angle Tow 

Composites 

Manufacturing processes to 

mitigate fabrication defects 

2012 [111] Haddadpour, 

Zamani (27) 

Curvilinear Fiber Optimization Tools for 

Aeroelastic Design of Composite Wings 

Flutter optimization of a towsteered thin walled beam 
17

2013 [120] Stodieck, 

Cooper, Weaver, 

Kealy (39) 

Improved Aeroelastic Tailoring Using TowSteered Composites Parameter studies of an aeroelastic 

flat plate 

3.1.4 Nonconventional Structural Designs 

Research in lightweight structural design covers various architectures, including trusses, curvilinear stiffeners, 

and stiffeners/ribs of various cross-sections or topologies. As previously mentioned, new manufacturing processes, 

such as the electron beam freeform fabrication (EBF3

) [106], can enable the fabrication of complex lightweight 

structures by depositing material rather than removing bulk material. The papers in Table 18 pertain to methods or 

concepts for reducing weight through detailed structural arrangement; direct aerodynamic interaction is not 

considered in most cases. 

Table 18. Papers on nonconventional structural design research. 

Year [Ref] Authors 

(#Cited works) 

Title Summary 

1990 [121] 

Swanson, 

Gurdal, 

Starnes (10) 

Structural Efficiency 

Study of GraphiteEpoxy Aircraft Rib 

Structures 

Compared rib designs comprised of corrugated panels, hatand blade-stiffened panels, and unstiffened flat panels using 

various combinations of axial compression, in-plane shear, 

and out-of-plane normal pressure loadings. The designs 

were highly dependent on the load conditions. Did not 

consider aerodynamics. 

1994 [122] 

Balabanov, 

Haftka (15) 

Topology Optimization 

of a Transport Wing 

Internal Structure 

Modeled the internal structure of a wing box with a dense 

lattice network of beams, and used topology optimization to 

find the best layout. 

2000 [123] Malla, 

Adib-Jahromi, 

Accorsi (37) 

Passive Vibration 

Suppression in TrussType Structures with 

Tubular Members 

Modeled a truss structure with an integrated damping 

element and found it difficult to characterize. Therefore they 

developed a tool for conducting quick parametric studies on 

damped truss designs. Did not consider aerodynamics. 

2000 [124] 

Campanile, 

Sachau (23) 

The Belt-Rib Concept: 

A Structronic Approach 

to Variable Camber 

Introduces the belt-rib concept for aircraft wing ribs that 

allow or produce (if actuated) variable camber. 

2001 [125] 

Eschenhauer, 

Olhoff (134) 

Topology Optimization 

of Continuum 

Structures: a Review 

Obtains the optimal topology of a rib cross-section under 

prescribed aerodynamic loads. 

2002 [126] Krog, 

Tucker, 

Rollema (2) 

Application of 

Topology Sizing and 

Shape Optimization 

Methods to Optimal 

Design of Aircraft 

Components 

Reduces the weight in ribs using topology optimization. 

Explains the challenges of modeling the load and boundary 

conditions accurately. Did not consider aerodynamics. 

2003 [127] Ragon, 

Gurdal, 

Haftka, Tzong 

(11) 

Bilevel Design of a 

Wing Structure Using 

Response Surfaces 

Proposes a technique for local size optimization of a panel 

stiffened with “upside down L-shaped” stiffeners. 

Considered weight, buckling, strength, and tip deflection. 

Did not consider aerodynamics. 

2003 [128] Murphy, 

Hinkle (20) 

Some Performance 

Trends In Hierarchical 

Truss Structures 

Determines that trusses having truss members comprised of 

trusses (i.e., 2nd order hierarchy) have better performance 

than other orders of hierarchy under certain conditions and 

assumptions. Assumptions are explained in the conclusions. 

Did not consider aerodynamics. 

2004 [129] 

Cadogan, 

Smith, 

Uhelsky, 

MacKusick 

(13) 

Morphing Inflatable 

Wing Development for 

Compact 

Package Unmanned 

Aerial Vehicles 

Discusses research on morphing inflatable wings. Proposes 

a concept of attaching an inflatable extension at a wing tip to 

increase wing aspect ratio. Describes ‘nastic’ structures 

which can undergo large strain while providing structural 

functions. 
18

2005 [130] 

Bushnell, 

Rankin (46) 

Optimum Design Of 

Stiffened Panels With 

Substiffeners 

Found that adding substiffeners to panels did not 

reduce the weight significantly. Did not consider 

aerodynamics. 

2005 [131] 

Campanile, 

Anders (26) 

Aerodynamic and 

Aeroelastic 

Amplification in 

Adaptive Belt-rib 

Airfoils 

Analyzes aeroelastic amplification to minimize the energy 

required to actuate the belt-rib concept. Actuation methods 

for the structure are not yet determined. 

2006 [132] 

Herencia, 

Weaver, 

Friswell (42) 

Local Optimisation of 

Long Anisotropic 

Laminated Fibre 

Composite 

Panels with T Shape 

Stiffeners 

Developed a two-step local optimization routine for a 

composite laminate panel with T-shaped stiffeners that 

enabled weight reduction. Considered a combined loading 

case along with strength, buckling, and manufacturing 

constraints. Did not consider aerodynamics. 

2008 [133] 

Bostandzhiyan

, Bokov, 

Shteinberg 

(11) 

Flexural Characteristics 

and Aerodynamic 

Aspects 

of the Design of the 

Bird Feather Shaft 

Describes how the bending stiffness of bird feather shafts 

enables high angles of attack without flow separation. It also 

shows how the cross-section of the bird feather shaft has a 

unique, asymmetric branching design for beneficial response 

in both downward and upward flapping. 

2009 [134] 

Cavagna, 

Ricci, 

Riccobene 

(38) 

A Fast Tool for 

Structural Sizing, 

Aeroelastic Analysis 

and Optimization in 

Aircraft Conceptual 

Design 

Developed an MDAO that includes weight calculation, 

aeroelastic analysis, and local structural sizing. Structural 

details such as the truss-core sandwich, unflanged integrally 

stiffened shell, and Z-stiffened shell are included in the 

optimization. 

2010 [135] Dang, 

Kapania, 

Slemp, Bhatia, 

Gurav (16) 

Optimization and 

Postbuckling Analysis 

of Curvilinear-Stiffened 

Panels Under Multiple 

Load Cases 

Describes how curvilinear stiffeners reduced the weight of a 

panel with holes by 7% compared to using straight stiffeners. 

Considered buckling, damage tolerance, stress, and 

crippling. Did not consider aerodynamics. 

2011 [136] 

Locatelli, 

Mulani, 

Kapania (39) 

Wing-Box Weight 

Optimization Using 

Curvilinear Spars and 

Ribs (SpaRibs) 

Describes how curvilinear stiffeners reduce the weight of 

wing boxes. Considered weight, buckling, and stress. Did 

not consider aerodynamics. 

2012 [137] Ning, 

Pellegrino (29) 

Design of Lightweight 

Structural Components 

for Direct Digital 

Manufacturing 

Optimizes the material arrangement within a beam’s crosssection for both minimum weight and maximum stiffness. 

Result is similar to an I-beam with most material at the top 

and bottom edges of the cross-section. The results show 

improved performance over solid beam (much improvement) 

and simple truss (little improvement). Did not compare to an 

I-beam though. 

2012 [138] 

Oremont, 

Schultz (18) 

An Efficient Analysis 

Methodology for 

Fluted-Core Composite 

Structures 

Presents an efficient analysis methodology for fluted-core 

sandwich composite panels that can be used to guide 

analyses for other structural concepts. 

2013 [139] Stanford, 

Beran (58) 

Aerothermoelastic 

Topology Optimization 

with Flutter and 

Buckling Constraints 

Optimizes the internal topology of a sandwich panel 

structure exposed to high-speed, high-temperature flow over 

its upper surface. Showed substantial improvements in 

unheated flutter boundaries, thermal buckling, and heated 

flutter boundaries. 

3.2 Active 

The benefits of aeroelastic tailoring can also be achieved through active means. For example, conventional 

materials and structures can be replaced with smart materials and structures whose properties or configurations 
19

change in response to external stimuli. Control effectors that directly interact with the air flow, such as control 

surfaces, can also be utilized for aeroelastic tailoring. Two examples of this are found in Zeiler and Weisshaar [140] 

and Weisshaar and Duke [18]. Table 19 includes survey papers on smart materials/structures and their application 

in aeronautics. In particular, Barbarino, et al. [10] are extremely thorough in their review of morphing aircraft and 

include a pictorial timeline of the morphing aircraft since the Wright Flyer, which includes the Mission Adaptive 

Wing of 1985, the Active Aeroelastic Wing of 2002, and numerous wings from university based research programs. 

Table 20 and Table 21 provide more detailed examples of smart structures and smart materials research in 

aircraft wing design, respectively. Despite the research invested in smart materials, Fontanazza, et al. [141] claim 

“the capability of current smart materials is relatively limited. Hence their use for morphing has mainly been 

applied to micro UAVs, which are subject to smaller wing loads and are easier and cheaper to flight test than 

traditional aircrafts.” Examples of smart materials application on the smaller scale are found in papers by Barret 

[142], Lim et al., [143], Vos et al., [144], and Stanford et al., [145]. Kornbluh, et al. [146] provides a thorough table 

of smart materials and their properties shown in Table 22 (many of these materials are also compared to one another 

in Figure 2). 

The materials in Table 22 are broken down into two categories “(1) materials whose intrinsic mechanical 

properties can be controlled, such as by the application of an electromagnetic field or thermal control, and (2) active 

materials that function as actuators and generators in adding to or subtracting from the elastic and viscous (damping) 

energy of deformation of the material and thereby effectively modulating the viscoelastic properties,” [146]. They 

add that “Each of these [smart] materials is suitable for some applications, but no single technology is capable of 

fast and efficient response that can produce a very wide range of stiffness and damping with a high elongation 

capability, that is, go from rubber to rigid.” For this reason, Kornbluh et al. [146] suggest configuring materials, 

structures, and mechanisms on the meso-scale to fabricate desired structural properties since “advances in microand nano-scale fabrication technologies could begin to allow us to make these meso-scale composite materials 

appear as true active materials.” 

Table 23 provides some examples of how the integration of materials and mechanisms can achieve a more 

desirable material or structural response. One of these examples is fluid flexible matrix composites (F2MC), which 

can be tailored to meet any of the properties depicted as open circles in Figure 2 (taken from Shan et al., [147]). 

Table 19. Survey papers on smart materials and structures that include aeronautical applications. 

Year [Ref] Authors (#Cited works) Title 

2000 [148] Giurgiutiu (65) Active-Materials Induced-Strain Actuation for Aeroelastic 

Vibration Control 

2004 [146] Kornbluh, Prahlad, Pelrine, 

Stanford, Rosenthal, von Guggenberg 

(35) 

Rubber to Rigid, Clamped to Undamped: Toward Composite 

Materials with Wide-Range Controllable Stiffness and 

Damping 

2006 [141] Fontanazza, Talling, Jackson, 

Dashwood, Dye, Iannucci (38) 

Morphing Wing Technologies Research 

2007 [149] Njuguna (160) Flutter Prediction, Suppression and Control in Aircraft 

Composite Wings as a Design Prerequisite: A Survey 

2011 [10] Barbarino, Bilgen, Ajaj, Friswell, 

Inman (342) 

A Review of Morphing Aircraft 

Table 20. Papers on structures designed to actively change wing stiffness, camber, and twist. 

Year [Ref] Authors 

(#Cited works) 

Title Overview 

2002 [150] Khot, 

Zweber, Veley, 

Oz, Eastep (7) 

Flexible Composite Wing 

with Internal Actuation for 

Roll Maneuver 

Developed a wing model that is actuated by 

antagonistic axial forces near the root to induce twist 

without ailerons. 

2003 [151] Kota, 

Hetrick, Osborn, 

Paul, Pendleton, 

Flick, Tilmann 

(14) 

Design and Application of 

Compliant Mechanisms 

for Morphing Aircraft 

Structures 

Developed conformable leading and trailing edge flaps. 
20

2003 [152] Zink, 

Raveh, Mavris 

(28) 

Integrated Trim and 

Structural Design Process 

for Active Aeroelastic 

Wing Technology 

Integrated active aeroelastic wing design process via 

ASTROS, with gear ratio and structural design 

variables. 

2004 [153] Chen, 

Sarhaddi, Jha, 

Liu, Griffin, 

Yurkovich (16) 

Variable Stiffness Spar 

Approach for Aircraft 

Maneuver Enhancement 

Using ASTROS 

Developed a variable stiffness spar, a “segmented spar 

having articulated joints at the connections with wing 

ribs and an electrical actuator capable of rotating the 

spar” for the F/A-18 pre-roll-modification aircraft 

model. Showed improvement in roll rate while 

satisfying deflection, flutter, and hinge moment 

constraints. 

2006 [154] Cooper 

(12) 

Adaptive Stiffness 

Structures for Air Vehicle 

Drag Reduction 

Developed demonstrative prototypes of wings of 

variable stiffness due to rotatable spars and movable 

spars in the chordwise direction. Still need to determine 

if the concept is scalable to larger aircraft. 

2006 [155] Maute, 

Reich (51) 

Integrated 

Multidisciplinary 

Topology Optimization 

Approach to Adaptive 

Wing Design 

Used topology optimization to determine the best 

arrangement of material, actuators, and pivot points 

within a wing’s cross-section to achieve desired 

external shape change. Couples an Euler CFD solver to 

a finite element method. 

Table 21. Papers that incorporate SMAs or piezoelectrics in wing design. 

Year [Ref] Authors 

(#Cited works) 

Title Overview 

1993 [156] Ehlers, 

Weisshaar (25) 

Static Aeroelastic Control of an 

Adaptive Lifting Surface 

Developed a non-dimensionalized laminated 

composite aeroelastic beam model having 

embedded piezoelectric actuators. Studied lift and 

lift effectiveness. Concluded that “strength 

parameters indicate that available materials may 

fall short of the demands that are placed upon 

them” and that “available actuator strength is 

inversely proportional to the wing loading W/S.” 

1996 [157] Nam, Kim, 

Weisshaar (25) 

Optimal Sizing and Placement 

of Piezo-Actuators for Active 

Flutter Suppression 

Optimized the thickness, location, and size of 

piezo-actuators on a non-dimensionalized 

composite plate wing model. Determined that 

flutter speed could be increased. 

2000 [158] Cesnik, 

Ortega-Morales, 

Patil (41) 

Active Aeroelastic Tailoring of 

High Aspect Ratio Composite 

Wings 

Developed a composite wing model with 

embedded piezoelectric strain actuators at the wind 

tunnel scale. Determined optimal actuator 

configurations for gust load alleviation, increased 

stability, and a combination of both objectives. 

2001 [159] Forster, 

Livne (21) 

Integrated Structure/Actuation 

Synthesis of Strain Actuated 

Devices for Shape Control 

Developed an approach for synthesizing devices 

for shape control using strain actuated devices. Did 

not account for aerodynamic loads. 

2002 [160] Nam, 

Chattopadhyay, 

Kim (21) 

Application of Shape Memory 

Alloy (SMA) Spars for Aircraft 

Maneuver Enhancement 

Modified an F-16 wing model to have two spars 

made of SMA material. Showed an increase in roll 

effectiveness. 

2004 [161] Kudva (15) Overview of the DARPA 

Smart Wing Project 

Demonstrated various benefits to actuating 

conformable leading and trailing edge surfaces 

with smart materials through several wind tunnel 

tests. Piezoelectric motors showed better 

performance over the SMA actuators. 
21

2004 [162] BartleyCho, Wang, 

Martin, Kudva, 

West (11) 

Development of High-rate, 

Adaptive Trailing Edge 

Control Surface for the Smart 

Wing Phase 2 Wind Tunnel 

Model 

Explains the various design concepts considered 

for the Smart Wing wind tunnel models with 

emphasis on the actuator and conformable control 

surface options. Describes the final designs in 

detail. 

Table 22. Comparison of smart materials by their properties (from Ref. [146]). 

Table 23. Papers on systems that manipulate the output of smart materials to achieve additional 

performance. 

Year [Ref] Authors 

(#Cited works) 

Title Overview 

2008 [163] Sofla, 

Elzey, Wadley 

(32) 

Two-way Antagonistic Shape 

Actuation Based on the One-way 

Shape Memory Effect 

Creates a two-way flexural actuator from 

combining a mechanism with (one-way) SMA 

actuators 

2009 [164] Philen, 

Phillips, Baur 

(30) 

Variable Modulus Materials 

based upon F2MC Reinforced 

Shape Memory Polymers 

Creates a highly variable modulus material by 

integrating ‘flexible matrix composite tubes 

having an active fluid-filling function’ into 

shape memory polymers, both of which already 

have variable modulus capabilities 
22

Figure 2. A comparison of smart materials based on their variable modulus capabilities. The open circles 

represent various F2MC configurations (from Ref. [147]). 

4 Conclusions 

Much of the applied aeroelastic tailoring work in aircraft wings has taken a more “global” approach by 

exploiting a single laminate orientation parameter within the wing skin. However, with newer manufacturing 

processes such as fiber tow steering and EBF3

, researchers have begun to focus their design efforts more locally 

along the wing with favorable results. Nonetheless, the greatest challenge is designing a high performance, 

lightweight wing that accounts for all factors encountered in flight. Many of the paper studies described above 

either simplify or ignore constraints to lessen the design problem’s complexity. For this reason, in at least one 

instance above, the outcomes of two papers somewhat contradict one another. Guo et al. [36] and Bohlmann and 

Scott [52] both discovered the various benefits of [-45/45]° ply orientations with respect to aeroelastic tailoring , but 

only Bohlmann and Scott accounted for strength, and realized that particular design had a weight penalty. As 

always, caution must be taken before directly applying the result of a research effort. In addition to aeroelastic 

tailoring approaches, numerous potentially enabling technologies are being studied today. Further research into 

these new capabilities may substantially deviate from the typical approach to aeroelastic tailoring and reveal game 

changers of either an active or passive nature. 

5 References 

[1] Shirk, M., Hertz, T., Weisshaar, T., “Aeroelastic Tailoring – Theory, Practice, Promise,” Journal of Aircraft, 

Vol. 23, No. 1, pp. 6-18, 1986. 

[2] Weisshaar, T., “Aircraft Aeroelastic Design and Analysis,” 1995 (second edition – 2009) 

https://engineering.purdue.edu/AAE/Academics/Courses/aae556/2010/Class%20notes%20Chapter%201., Feb, 

21, 2012. 

[3] Munk, M., "Propeller Containing Diagonally Disposed Fibrous Material," U.S. Patent 2,484,308,1111, Oct. 

1949. 

[4] Bucci, R., Warren, C., Starke, E., “Need for New Materials in Aging Aircraft Structures,” Journal of Aircraft, 

Vol. 37, No. 1, pp. 122-129, 2000. 

[5] Kuzmina, S., Amiryants, G., Schwseiger, J., Cooper, J., Amprikidis, M., Sensburg, O., “Review and Outlook 

on Active and Passive Aeroelastic Design Concepts for Future Aircraft,” ICAS 2002 Proceedings, 

International Council of the Aeronautical Sciences/AIAA, 2002. 

[6] Siochi, E., Anders, J., Cox, D., Jegley, D., Fox, R., Stephen, J. “Biomimetics for NASA Langley Research 

Center,” Hampton, VA, February 2002. 

[7] Livne, E., “Future of Airplane Aeroelasticity,” Journal of Aircraft, Vol. 40, No. 6, pp. 1066-1092, 2003. 

[8] Livne, E. Weisshaar, T., "Aeroelasticity of Nonconventional Airplane Configurations - Past and Future," 

Journal of Aircraft, Vol. 40, No. 6, pp. 1047-1065, 2003. 

[9] Renton, J., Olcott, D., Roeseler, B., Batzer, R., Baron, B., Velicki, A., “Future of Flight Vehicle Structures 

(2002-2023),” Journal of Aircraft, Vol. 41, No. 5, pp. 986–998, 2004. 
23

[10] Barbarino, S., Bilgen, O., Ajaj, R., Friswell, M., Inman, D., “A Review of Morphing Aircraft,” Journal of 

Intelligent Material Systems and Structures, Vol. 22, pp. 823-877, 2011. 

[11] McCullers, L., Lynch, R., “Dynamic Characteristics of Advanced Filamentary Composite Structures, Volume 

II—Aeroelastic Synthesis Procedure Development,” AFFDL-TR-73-111, Sept. 1974. 

[12] Haftka, R., Starnes, J., “WIDOWAC, Wing Design Optimization with Aeroelastic Constraints: Program 

Manual,” NASA TM X-3071, 1974. 

[13] Wilkinson, K., Markowitz, J., Lerner, E., George, D., Batill, S., “FASTOP: A Flutter and Strength 

Optimization Program for Lifting-Surface Structures,” Journal of Aircraft, Vol. 14, No. 6, pp. 581-587, 1977. 

[14] Neill, D., Johnson, E., Canfield, R., “ASTROS—A Multidisciplinary Automated Structural Design Tool,” 

Journal of Aircraft, Vol. 27, No. 12, pp. 1021–1027, 1990. 

[15] Venkayya, V., Tischler, V., “Aerodynamics - Structures Interaction in Airframe Design,” 

http://www.mscsoftware.com/support/library/conf/auc97/p01097.pdf, retrieved Jun 18, 2012. 

[16] Zona Technology, Inc. “ASTROS – A Next Generation Aircraft Design System,” retrieved Jun 18, 2012. 

[17] Weisshaar, T., Nam, C., Batista-Rodriguez, A., “Aeroelastic Tailoring for Improved UAV Performance,” AIAA 

Structures, Structural Dynamics, and Materials Conference, Long Beach, CA, April 20-23, 1998. 

[18] Weisshaar, T., Duke, D., “Induced Drag Reduction Using Aeroelastic Tailoring with Adaptive Control 

Surfaces,” Journal of Aircraft, Vol. 43, No. 1, pp. 157-164, 2006. 

[19] Weisshaar, T., Ryan, R., “Control of Aeroelastic Instabilities Through Stiffness Cross-Coupling,” Journal of 

Aircraft, Vol. 23, No. 3, pp. 148-155, 1986. 

[20] Weisshaar, T., “Aeroelastic Tailoring—Creative Uses of Unusual Materials,” AIAA Paper 87-0976, 1987. 

[21] Eastep, F., Tischler, V., Venkayya, V., Khot, N., “Aeroelastic Tailoring of Composite Structures,” Journal of 

Aircraft Vol. 36, No. 6, pp. 1041-1047, 1999. 

[22] Ghiasi, H., Pasini, D., Lessard, L. “Optimum Stacking Sequence Design of Composite Materials, Part I: 

Constant Stiffness Design,” Composite Structures, Vol. 90 pp. 1-11, 2009. 

[23] Green, J., “Aeroelastic Tailoring of Aft-Swept High-Aspect-Ratio Composite Wings,” Journal of Aircraft, 

Vol. 24, No. 11, pp. 812-819, 1987. 

[24] Isogai, K., “Direct Search Method to Aeroelastic Tailoring of a Composite Wing Under Multiple Constraints,” 

Journal of Aircraft, Vol. 26, No. 12, pp. 1076–1080, 1989. 

[25] Visser, J., “Aeroelastic and Strength Optimisation of a Composite Aircraft Wing Using a Multilevel 

Approach”. AIAA-99-1258, 1999. 

[26] Qin, Z., Marzocca, P., Librescu, L., “Aeroelastic Instability and Response of Advanced Aircraft Wings at 

Subsonic Flight Speeds,” Aerospace Science and Technology, Vol. 6, pp. 195–208, 2002. 

[27] Hirano, Y., Todoroki, A., “Stacking Sequence Optimizations for Composite Laminates using Fractal Branch 

and Bound Methods: Applications for Supersonic Panel Flutter Problem with Buckling Load Condition,” 

Advanced Composite Materials, Vol. 13, No. 2, pp. 89-106, 2004. 

[28] Kim, T., Hwang, I., “Optimal Design of Composite Wing Subjected to Gust Loads,” Computers and Structures

Vol. 83, pp. 1546-1554, 2005. 

[29] Seresta, O., Abdalla, M., Mulani, S., Marzocca, P., “Stacking Sequence Design of Flat Composite Panel for 

Flutter and Thermal Buckling,” AIAA Journal, Vol. 44, No. 11, pp. 2726-2735, 2006. 

[30] Kim, D., Oh, S., Lee, I., Kweon, J., Choi, J., “Weight Optimization of Composite Flat and Curved Wings 

Satisfying Both Flutter and Divergence Constraints,” Key Engineering Materials, Vol. 334, pp. 477-480, 2007. 

[31] Kameyama, M., Fukunaga, H., “Optimum Design of Composite Wings for Aeroelastic Characteristics using 

Lamination Parameters,” Computers and Structures, Vol. 85, No. 3, pp. 213-224, 2007. 

[32] Manan, A., Cooper, J., “Uncertainty of Composite Wing Aeroelastic Behavior,” AIAA 2008-5868, 2008. 

[33] Harmin, Y., Cooper, J., “Aeroelastic Tailoring Using Ant Colony Optimisation”, AIAA Structures, Structural 

Dynamics, and Materials Conference, Palm Springs, California, May 4-7, 2009. 

[34] Attaran, A., Majid, D., Basri, S., Mohd Rafie, A., Abdullah, E., “Structural Optimization of an Aeroelastically 

Tailored Composite Flat Plate Made of Woven Fiberglass/Epoxy,” Aerospace Science and Technology, Vol. 

15, No. 5, pp. 393-401, 2011. 

[35] De Leon, D., de Souza, C., Fonseca, J., da Silva, R., “Aeroelastic Tailoring Using Fiber Orientation and 

Topology Optimization,” Structural and Multidisciplinary Optimization, Vol. 46, pp. 663-677, 2012. 

[36] Guo, S., Cheng, W., Cui, D., “Aeroelastic Tailoring of Composite Wing Structures by Laminate Layup 

Optimization,” AIAA Journal. Vol. 44, No. 12, pp. 3146-3149, 2006. 

[37] Guo, S., “Aeroelastic Optimization of an Aerobatic Wing Structure,” Aerospace Science and Technology, Vol. 

11, pp. 396-404, 2007. 
24

[38] Herencia, J., Weaver, P., Friswell, M., “Morphing Wing Design via Aeroelastic Tailoring,” AIAA Structures, 

Structural Dynamics, and Materials Conference, Honolulu, Hawaii, April 23-26, 2007. 

[39] Chang, N., Yang, W., Wang, J., Wang, W., “Design Optimization of Composite Wing Box for Flutter and 

Stiffness,” AIAA Aerospace Sciences Meeting, Orlando, Florida, January 4-7, 2010. 

[40] Haftka, R., “Parametric Constraints with Application to Optimization for Flutter Using a Continuous Flutter 

Constraint,” AIAA Journal, Vol. 13, pp. 471-475, 1975. 

[41] Stroud, W., Krishnamurthy, T., Mason, B., Smith, S., Naser, A., “Probabilistic Design of a Plate-Like Wing to 

Meet Flutter and Strength Requirements,” AIAA Structures, Structural Dynamics, and Materials Conference, 

Denver, CO, April 22-25, 2002. 

[42] Martins, J., Alonso, J., Reuther, J., “High-Fidelity Aero-Structural Design Optimization of a Supersonic 

Business Jet,” AIAA Structures, Structural Dynamics and Materials Conference, Denver, CO, April 22-25, 

2002. 

[43] Maute, K., Allen, M. “Conceptual Design of Aeroelastic Structures by Topology Optimization,” Structural 

and Multidisciplinary Optimization, Vol. 27, pp. 27-42, 2004. 

[44] Odaka, Y., Furuya, H., “Robust Structural Optimization of Plate Wing Corresponding to Bifurcation in Higher 

Mode Flutter,” Structural and Multidisciplinary Optimization, Vol. 30, No. 6, pp. 1-12, 2005. 

[45] Gomes, A., Suleman, A., “Topology Optimization of a Reinforced Wing Box for Enhanced Roll Maneuvers,” 

AIAA Journal, Vol. 46, No. 3, pp. 548–556, 2008. 

[46] Kobayashi, M., Pedro, H., Kolonay, R., Reich, G., “On a Cellular Division Method for Aircraft Structural 

Design,” The Aeronautical Journal, Vol. 113, No. 1150, pp. 821-831, 2009. 

[47] Stanford, B., Beran, P., “Optimal Structural Topology of a Plate-Like Wing for Subsonic Aeroelastic 

Stability,” Journal of Aircraft, Vol. 48, No.4, pp. 1193-1203, 2011. 

[48] Harmin, M., Ahmed, A., Cooper, J., Bron, F., “Aeroelastic Tailoring of Metallic Wing Structures,” AIAA 

Structures, Structural Dynamics and Materials Conference, Denver, Colorado, April 4-7, 2011. 

[49] Stanford, B., Beran, P., “Computational Strategies for Reliability-Based Structural Optimization of Aeroelastic 

Limit Cycle Oscillations,” Structural and Multidisciplinary Optimization, Vol. 45, No. 1, pp. 83-99, 2012. 

[50] Sleesongsom, S., Bureerat, S., “New Conceptual Design of Aeroelastic Wing Structures by Multi-Objective 

Optimization,” Engineering Optimization, Vol. 45, No. 1, pp. 1-16, 2012. 

[51] Dunning, P., Brampton, C., Kim, H., “Multidisciplinary Level Let Topology Optimization of the Internal 

Structure of an Aircraft Wing,” World Congress on Structural and Multidisciplinary Optimization, Orlando, 

FL, May 19-24, 2013. 

[52] Bohlmann, J., Scott, R., “A Taguchi Study of the Aeroelastic Tailoring Design Process,” AIAA Structures, 

Structural Dynamics, and Materials Conference, Baltimore, Maryland, April 8-10, 1991. 

[53] Rehfield, L., Chang, S., Zischka, P., “Modeling and Analysis Methodology for Aeroelastically Tailored 

Chordwise Deformable Wings,” NASA Contractor Report 189620, July 1992. 

[54] Arizono, H., Isogai, K., Application of Genetic Algorithm for Aeroelastic Tailoring of a Cranked-Arrow 

Wing,” Journal of Aircraft, Vol. 42, No. 2, pp. 493-499, 2005. 

[55] Kennedy, G., Martins, J., “A Comparison of Metallic and Composite Aircraft Wings using Aerostructural 

Design Optimization,” AIAA Paper 2012-5475. 

[56] Dillinger, J., Klimmek, T., Abdalla, M., Gürdal, Z., “Stiffness Optimization of Composite Wings with 

Aeroelastic Constraints,” Journal of Aircraft, Vol. 50, No. 4, pp. 1159-1168, 2013. 

[57] Seyranian, A., “Sensitivity Analysis and Optimization of Aeroelastic Stability,” International Journal of Solids 

an Structures, Vol. 18, No. 9, pp. 791-807, 1982. 

[58] Craig, A., McLean J., “Spanload Optimization for Strength Designed Lifting Surfaces,” AIAA Applied 

Aerodynamics Conference, Williamsburg, VA, June 6-8, 1988. 

[59] Butler, R., Banerjee, J., “Optimum Design of Bending-Torsion Coupled Beams with Frequency or Aeroelastic 

Constraints,” Computers and Structures, Vol. 60, No. 5, pp. 715-724, 1996. 

[60] Barboni, R., Mannini, A., Gaudenzi, P., “On the Use of the P-TFE Method for Panel Flutter Optimization,” 

Computers and Structures, Vol. 70, No. 1, pp. 109-117, 1999. 

[61] Langthjem, M., Sugiyama, Y., “Optimum Shape Design Against Flutter of a Cantilevered Column With an 

End-Mass of Finite Size Subjected to a Non-Conservative Load,” Journal of Sound and Vibration, Vol. 226, 

No. 1, pp. 1-23, 1999. 

[62] Lemanski, S., Weaver, P., “Flap-Torsion Coupling in Prismatic Sections”, AIAA Structures, Structural 

Dynamics, and Materials Conference, Palm Springs, CA, April 19-22, 2004. 

[63] Palaniappan, K., Beran, P., Jameson, A., “Optimal Control of LCOs in Aero-Structural Systems,” AIAA 

Structures, Structural Dynamics, and Materials Conference, Newport, RI, May 1-4, 2006. 
25

[64] Pastilha, P., “Structural Optimization for Flutter Instability Problems,” Master’s Thesis, Technical University 

of Lisbon, Mechanical Engineering Department, 2007. 

[65] Stanford, B., Beran, P., “Direct Flutter and Limit Cycle Computations of Highly-Flexible Wings for Efficient 

Analysis and Optimization,” Journal of Fluids and Structures, Vol. 36, pp. 111-123, 2013. 

[66] Boynton, R. Wiener, K., “Measuring Mass Properties of Aircraft Control Surfaces,” Tech. Rep., S.A.W.E. 

Inc., 2000. 

[67] Regis, A., de Mattos, B., da Mota Girardi, R., “Wing Structural Weight Evolution with the Cruise Mach 

Number of a Commercial Transport Aircraft,” Applied Aerodynamics Conference and Exhibit Providence, RI, 

August 16-19, Providence, Rhode Island. 

[68] Stanford, B., Ifju, P., Albertani, R., Shyy, W., “Fixed Membrane Wings for Micro Air Vehicles: Experimental 

Characterization, Numerical Modeling, and Tailoring,” Progress in Aerospace Sciences, Vol. 44, No. 4, pp. 

258-294, 2008. 

[69] Stanford, B., Ifju, P., “Aeroelastic Topology Optimization of Membrane Structures for Micro Air Vehicles,” 

Structural and Multidisciplinary Optimization, Vol. 38, No. 3, pp. 301/316, 2009. 

[70] Stanford, B., Ifju, P., “Multi-Objective Topology Optimization of Wing Skeletons for Aeroelastic Membrane 

Structures,” International Journal of Micro Air Vehicles, Vol. 1, No. 1, pp. 51-69, 2009. 

[71] Iglesias, S., Mason, W., “Optimum Spanloads Incorporating Wing Structural Weight,” AIAA Aircraft 

Technology, Integration, and Operations Forum, Los Angeles, CA, October 16-18, 2001. 

[72] Pettit, C., Grandhi, R., “Optimization of a Wing Structure for Gust Response and Aileron Effectiveness”, 

Journal of Aircraft, Vol. 40, No. 6, pp. 1185-1191, 2003. 

[73] Papila M., Haftka R., Mason W., Alves R., "Tailoring Wing Structures for Reduced Drag Penalty in OffDesign Flight Conditions", AIAA Multidisciplinary Analysis and Optimization and Conference, Albany, NY, 

August 30-September 1, 2004. 

[74] Love, M., Zink, P., Wieselmann, P., Youngren, H., "Body Freedom Flutter of High Aspect Ratio Flying 

Wings," AIAA Structures, Structural Dynamics, and Materials Conference, Austin, TX, April 18-21, 2005. 

[75] Wang, Z., Liu, D., Tang, C., Yang, C., “The Influence of Spar Position on Aeroelastic Optimization of a Large 

Aircraft Wing,” Sceince China Technological Sciences, Vol. 55, No. 1, pp. 117-124, 2012. 

[76] Livne, E., Schmit, L., Friedmann, P., “An Integrated Approach to the Optimum Design of Actively Controlled 

Composite Wings,” AIAA Paper 89-1268, 1989. 

[77] Komarov, V., Weisshaar, T., "Aircraft Structural Design–Improving Conceptual Design Level Fidelity," AIAA 

Symposium on Multidisciplinary Analysis and Optimization, St. Louis, MO, September 2-4, 1998. 

[78] Blair, M., Hill, S., Weisshaar, T., Taylor, R., “Rapid Modeling with Innovative Structural Concepts”, AIAA 

Paper 98-1755, 1998. 

[79] Livne, E., Navarro, I., “Nonlinear Equivalent Plate Modeling of Wing Box Structures,” Journal of Aircraft, 

Vol. 36, No. 5, pp. 34-41, 1999. 

[80] Reuther, J., Alonso, J., Martins, J., Smith, S., “A Coupled Aero-Structural Optimisation Method for Complete 

Aircraft Configurations,” AIAA Aerospace Science Meeting and Exhibit, Reno, NV, January 11-14, 1999. 

[81] Gumbert, C., Hou, G., Newman, P., “Simultaneous Aerodynamic and Structural Analysis and Design 

Optimization (SASDO) for a 3-DWing,” AIAA Paper 2001-2527, 2001. 

[82] Demasi, L., Livne, E., “Dynamic Aeroelasticity of Structurally Nonlinear Configurations using Linear Modally 

Reduced Aerodynamic Generalized Forces,” AIAA Journal, Vol. 47, No. 1, pp. 56-67, 2009. 

[83] Yoon, G., “Topology Optimization for Stationary Fluid-Structure Interaction Problems using a New 

Monolithic Formulation,” International Journal for Numerical Methods in Engineering, Vol. 82, No. 5, pp. 

591-616, 2010. 

[84] Fazelzadeh, S., Marzocca, P., Mazidi, A., Rashidi, E., “Divergence and Flutter of Shear Deformable Aircraft 

Swept Wings Subjected to Roll Angular Velocity,” Acta Mechanica, Vol. 212, pp. 151–165 2010. 

[85] Seeger, J., Wolf, K., "Multi-Objective Design of Complex Aircraft Structures using Evolutionary Algorithms." 

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, Vol. 225, 

No. 10, pp. 1153-1164, 2011. 

[86] Bhatia, M., Kapania, R., Haftka, R., “Structural and Aeroelastic Characteristics of Truss-Braced Wings: A 

Parametric Study”, Journal of Aircraft, Vol. 49, pp. 302-310, 2012. 

[87] Daoud, F., Petersson, O., Deinert, S., Bronny, P., “Multidisciplinary Airframe Design Process: Incorporation 

of Steady and Unsteady Aeroelastic Loads,” AIAA Aviation Technology, Integration, and Operations 

Conference, Indianapolis, IN, September 17-19, 2012. 

[88] Mortensen, A., Llorca, J., “Metal Matrix Composites,” Annual Review of Materials Research, Vol. 40, pp. 

243-270, 2010. 
26

[89] Miracle D., “Aeronautical Applications of Metal Matrix Composites,” In ASM Handbook, Miracle, D., 

Donaldson S., (editors), Composites, vol. 21. Materials Park: ASM International, pp. 1043–9, 2001. 

[90] Miracle, D., “Metal Matrix Composites–from Science to Technological Significance.” Composites Science and 

Technology, Vol. 65, pp. 15–16, 2005. 

[91] “GLARE,” Wikipedia, The Free Encyclopedia. Wikimedia Foundation, Inc. 12 May 2012, Web. 18, Retrieved 

June 2012. 

[92] Alderliesten, R., Benedictus, R., “Fiber/Metal Composite Technology for Future Primary Aircraft Structures,” 

AIAA Structures, Structural Dynamics, and Materials Conference, Honolulu, HI, April 23-26, 2007. 

[93] Bednarcyk, B., Yarrington, P., Lucking, R., Collier, C., Ainsworth, J., “Efficient Design and Analysis of 

Lightweight Reinforced Core Sandwich and PRSEUS Structures,” AIAA Structures, Structural Dynamics, and 

Materials Conference, Denver, Colorado April 4–7, 2011. 

[94] Ibrahim, A., Mohamed, A., Lavernia, E., “Particulate Reinforced Metal Matrix Composites - A Review,” 

Journal of Material Science, Vol. 26, pp. 1137-1156, 1991. 

[95] Degischer, H., “Innovative Light Metals: Metal Matrix Composites and Foamed Aluminum,” Materials and 

Design, Vol. 18, No. 4, pp. 221-226, 1997. 

[96] Kaczmar, J., Pietrzak, Wlosinski, K., “The Production and Application of Metal Matrix Composite Materials,” 

Journal of Material Science and Process Technology, Vol. 106, pp. 45-49, 2000. 

[97] Rawal, S., “Metal-Matrix Composites for Space Applications,” JOM, Vol. 53, No. 4, pp. 14-17, 2001. 

[98] Fernández, R., González-Doncel, G., “Additivity of Reinforcing Mechanisms during Creep of Metal Matrix 

Composites: Role of the Microstructure and the Processing Route,” Journal of Alloys and Compounds, Vol. 

475, No. 1, pp. 202-206, 2009. 

[99] Scherm, F., Volkl, R., van Smaalen, S., Mondal, S., Plamondon, P., L’Esperance, G., Bechmann, F., Glatzel, 

U., “Microstructural Characterization of Interpenetrating Light Weight Metal Matrix Composites,” Materials 

Science and Engineering: A, Vol. 518, No. 1, pp. 118-123, 2009. 

[100]Ricks, T., Lacy, T., Bednarcyk, B., Arnold, S., “A Multiscale Modeling Methodology for Metal Matrix 

Composites Including Fiber Strength Stochastics,” AIAA Structures, Structural Dynamics and Materials 

Conference, Honolulu, Hawaii, April 23-26, 2012. 

[101]Slingerland, R., van Rijn van Alkemade, F., Vermeulen, B., “A Preliminary Prediction Method for the Effect 

of New Fuselage Materials on Transport Aircraft Weight,” AIAA Structures, Structural Dynamics, and 

Materials Conference, Honolulu, HI, April 23-26, 2007. 

[102]Schmidt, H., Schmidt-Brandecker, B., “Damage Tolerant Design and Analysis of Current and Future Aircraft 

Structures,” AIAA/ICAS International Air and Space Symposium and Exposition: the Next 100 Years, Dayton, 

OH, July 14-17, 2003. 

[103]Seo, H., Hundley, J., Hahn, H., Yang, J., “Numerical Simulation of Glass-Fiber-Reinforced Aluminum 

Laminates with Diverse Impact Damage,” AIAA Journal, Vol. 48, No. 3, pp. 1-10, 2010. 

[104]Marzocca, P., Fazelzadeh, S., Hosseini, M., “A Review of Nonlinear Aero-Thermo-Elasticity of Functionally 

Graded Panels,” Journal of Thermal Stresses, Vol. 34, pp. 536-568, 2011. 

[105]Venkataraman, S., Sankar, B., “Elasticity Analysis and Optimization of a Functionally Graded Plate with 

Hole”, AIAA Paper 2003-1466, 2003. 

[106]Taminger, K., Hafley, R., “Electron Beam Freeform Fabrication: A Rapid Metal Deposition Process.” 

Proceedings of the 3rd Annual Automotive Composites Conference, Troy, MI, September 9-10, 2003. 

[107]Cooper, A., “Trajectorial Fiber Reinforcement of Composite Structures,” Ph. D. Dissertation, Washington 

University, St. Louis, Missouri, 1972. 

[108]Kisch, R., “Automated Fibre Placement Historical Perspective,” Proceedings of the SAMPE International 

Symposium, Long Beach, CA, 2006. 

[109]Butler, R., Baker, N., Liu, W., “Damage Tolerance of Buckling Optimized Variable Angle Tow Panels,” AIAA 

Structures, Structural Dynamics, and Materials Conference, Palm Springs, CA, May 4-7, 2009. 

[110]Ghiasi, H., Fayazbakhsh, K., Pasini, D., Lessard, L., “Optimum Stacking Sequence Design of Composite 

Materials, Part II: Variable Stiffness Design,” Composite Structures, Vol. 93 pp. 1-13, 2010. 

[111]Haddadpour, H., Zamani, Z., “Curvilinear Fiber Optimization Tools for Aeroelastic Design of Composite 

Wings,” Journal of Fluids and Structures, Vol. 33, pp. 180-190, 2012. 

[112]Ijsselmuiden, S., Abdalla, M., Gürdal, Z., “Optimization of Variable-Stiffness Panels for Maximum Buckling 

Load Using Lamination Parameters,” AIAA Journal, Vol. 48, No. 1, pp. 134-143, 2010. 

[113]Weaver, P., Potter, K., Hazra, K., Saverymuthapulle, M., Hawthorne, M,. “Buckling of Variable Angle Tow 

Plates: From Concept to Experiment,” AIAA Structures, Structural Dynamics, and Materials Conference, Palm 

Springs, CA, May 4-7, 2009. 
27

[114]Alhajahmad, A., Abdalla, M., Gürdal, Z., “Optimal Design of Tow-Placed Pressurized Fuselage Panels for 

Maximum Strength with Buckling Considerations,” Journal of Aircraft, Vol. 47, pp. 775-782, 2010. 

[115]Honda, S., Narita, Y., Sasaki, K., “Maximizing the Fundamental Frequency of Laminated Composite Plates 

With Optimally Shaped Curvilinear Fibers,” Journal of System Design and Dynamics, Vol. 3, No. 6, pp. 867-

876, 2009. 

[116]Tatting, B., Setoodeh, S., Gürdal, Z., “Enhancements of Tow-Steering Design Techniques: Design of 

Rectangular Panel Under Combined Loads,” NASA CR-2005-213911, 2005. 

[117]Lopes, C., Gürdal, Z., Camanho, P., “Tailoring for Strength of Composite Steered-Fibre Panels with Cutouts,” 

Composites Part A: Applied Science and Manufacturing, Vol. 41, No. 12, pp. 1760-1767, 2010. 

[118]Croft, K., Lessard, L., Pasini, D., Hojjati, M., Chen, J., Yousefpour, A., “Experimental Study of the Effect of 

Automated Fiber Placement Induced Defects on Performance of Composite Laminates,” Composites Part A: 

Applied Science and Manufacturing, Vol. 42, pp. 484-491, 2011. 

[119]Kim, B., Potter, K., Weaver, P., “Continuous Tow Shearing for Manufacturing Variable Angle Tow 

Composites,” Composites Part A: Applied Science and Manufacturing, Vol. 43, No. 8pp. 1347-1356, 2012. 

[120]Stodiek, O., Cooper, J., Weaver, P., Kealy, P., “Improved Aeroelastic Tailoring Using Tow-Steered 

Composites,” Composite Structures, Vol. 106, pp. 703-715, 2013. 

[121]Swanson, G., Gürdal, Z., Starnes, J., “Structural Efficiency Study of Graphite-Epoxy Aircraft Rib Structures, 

Journal of Aircraft, Vol. 27, No. 12, pp. 1011-1020, 1990. 

[122]Balabanov, V., Haftka, R., “Topology Optimization of a Transport Wing Internal Structure,” AIAA Paper 94-

4414. 

[123]Malla, R., Adib-Jahromi, H., Accorsi, M., “Passive Vibration Suppression in Truss-Type Structures with 

Tubular Members,” Journal of Spacecraft and Rockets, Vol. 37, No. 1, pp. 1-12, 2000. 

[124]Campanile, L., Sachau, D., “The Belt-Rib Concept: a Structronic Approach to Variable Camber”, Journal of 

Intelligent Material Systems and Structures, Vol. 11, pp. 215-224, 2000. 

[125]Eschenauer, H., Olhoff, N., “Topology Optimization of Continuum Structures: a Review,” Applied Mechanics 

Reviews, Vol. 54, No. 4, pp. 331-390, 2001. 

[126]Krog, L., Tucker, A., Rollema, G., “Application of Topology, Sizing and Shape Optimization Methods to 

Optimal Design of Aircraft Components”, Airbus UK Ltd, Altair Engineering Ltd., 2002. 

[127]Ragon, S., Gürdal, Z., Haftka, R., Tzong, T., “Bilevel Design of a Wing Structure Using Response Surfaces,” 

Journal of Aircraft, Vol. 40, No. 5, pp. 1-12, 2003. 

[128]Murphy, T., Hinkle, J., “Some Performance Trends in Hierarchical Truss Structures,” AIAA Structures, 

Structural Dynamics, and Materials Conference, Norfolk, VA, April 7-10, 2003. 

[129]Cadogan, D., Smith, T., Uhelsky, F., Mackusick, M., “Morphing Inflatable Wing Development for Compact 

Package Unmanned Aerial Vehicles,” AIAA Structures, Structural Dynamics, and Materials Conference, Palm 

Springs, CA, April 7-10, 2004. 

[130]Bushnell, D., Rankin, C., “Optimum Design of Stiffened Panels with Sub-Stiffeners,” AIAA Structures, 

Structural Dynamics, and Materials Conference, Austin, TX, April 18-21, 2005. 

[131]Campanile, L., Anders, S., "Aerodynamic and Aeroelastic Amplification in Adaptive Belt-Rib Airfoils." 

Aerospace Science and Technology, Vol. 9, No. 1, pp. 55-63, 2005. 

[132]Herencia, J., Weaver, P., Friswell, M., “Local Optimisation of Long Anisotropic Laminated Fibre Composite 

Panels with T Shape Stiffeners,” AIAA Structures, Structural Dynamics, and Materials Conference, Newport, 

RI, May 1-4, 2006. 

[133]Bostandzhiyan, S., Bokov, A., Shteinberg, A., “Flexural Characteristics and Aerodynamic Aspects of the 

Design of the Bird Feather Shaft,” Technical Physics, Vol. 422, No. 1, pp. 36-39, 2008. 

[134]Cavagna, L., Ricci, S., Riccobene, L., “A Fast Tool for Structural Sizing, Aeroelastic Analysis and 

Optimization in Aircraft Conceptual Design,” AIAA Structures, Structural Dynamics, and Materials 

Conference, Palm Springs, CA, May 1-4, 2009. 

[135]Dang, T., Kapania, R., Slemp, W., Bhatia, M., Gurav, S., “Optimization and Postbuckling Analysis of 

Curvilinear-Stiffened Panels Under Multiple-Load Cases,” Journal of Aircraft, Vol. 47, No. 5, pp. 1-12, 2010. 

[136]Locatelli, D., Mulani, S., Kapania, R., “Wing-Box Weight Optimization Using Curvilinear Spars and Ribs 

(SpaRibs),” Journal of Aircraft, Vol. 48, No. 5, pp. 68-79, 2011. 

[137]Ning, X., Pellegrino, S., “Design of Lightweight Structural Components for Direct Digital Manufacturing,” 

AIAA Structures, Structural Dynamics and Materials Conference, Honolulu, Hawaii, April 23-26, 2012. 

[138]Oremont, L., Schultz, M., “An Efficient Analysis Methodology for Fluted-Core Composite Structures,” AIAA 

Structures, Structural Dynamics and Materials Conference, Honolulu, Hawaii, April 23-26, 2012. 
28

[139]Stanford, B., Beran, P., “Aerothermoelastic Topology Optimization with Flutter and Buckling Constraints,” 

Structural and Multidisciplinary Optimization, Vol. 48, No. 1, pp. 149-171, 2013. 

[140]Zeiler, T., Weisshaar, T., “Integrated Aeroservoelastic Tailoring of Lifting Surfaces,” AIAA Paper 86-1005, 

1986. 

[141]Fontanazza, F., Talling, R., Jackson, M., Dashwood, R., Dye D., Iannucci, L., “Morphing Wing Technologies 

Research,” Seas DTC First Annual Conference, 2006. 

[142]Barrett, R., “Active Aeroelastic Tailoring of an Adaptive Flexspar Stabilator,” Smart Materials and Structures, 

Vol. 5, pp. 723-730, 1996. 

[143]Lim, S., Lee, S., Park, H., Yoon, K., Goo, N., “Design and Demonstration of a Biomimetic Wing Section 

Using a Lightweight Piezo-Composite Actuator (LIPCA),” Smart Materials and Structures, Vol. 14, pp. 496-

503, 2005. 

[144]Vos, R., Barrett, R., de Breuker, R., Tiso, P., “Post-Buckled Precompressed Elements: a New Class of Control 

Actuators for Morphing Wing UAVs,” Smart Materials and Structures, Vol. 16, pp. 919-926, 2007. 

[145]Stanford, B., Abdulrahim, M., Lind, R., Ifju, P., “Investigation of Membrane Actuation for Roll Control of a 

Micro Air Vehicle,” Journal of Aircraft, Vol. 44, No. 3, pp. 741–749, 2007. 

[146]Kornbluh, R., Pelrine, R., Prahlad, H., Stanford, S., Rosenthal, M., von Guggenberg, P., “Rubber to Rigid, 

Clamped to Undamped: Towards Composite Materials With Wide-Range Controllable Stiffness and 

Damping,” Smart Structures and Materials 2004: Industrial and Commercial Applications of Smart Structures 

Technologies, E. Anderson (editor), Proc. SPIE, Vol. 5388, 2004. 

[147]Shan, Y., Lotfi, A., Philen, M., Li, S., Bakis, C., Rahn, C., Wang, K., “Fluidic Flexible Matrix Composites for 

Autonomous Structural Tailoring,” Proceedings of SPIE, the International Society for Optical Engineering, 

Vol. 6525, 2007. 

[148]Giurgiutiu, V., “Active-Materials Induced-Strain Actuation for Aeroelastic Vibration Control,” Shock and 

Vibration Digest, Vol. 32, pp. 355–368, 2000. 

[149]Njuguna, J., “Flutter Prediction, Suppression and Control in Aircraft Composite Wings as a Design 

Prerequisite: A Survey,” Structural Control and Health Monitoring, Vol. 14, No. 5pp. 715-758, 2007. 

[150]Knot, N., Zweber, J., Veley, D., Oz, H., Eastep, F., “Flexible Composite Wing with Internal Actuation for Roll 

Maneuver,” Journal of Aircraft. Vol. 39, No. 4, pp. 521-527, 2002. 

[151]Kota, S., Hetrick, J., Osborn, R., Paul, D., Pendleton, E., Flick, P., Tilmann, C., “Design and Application of 

Compliant Mechanisms for Morphing Aircraft Structures”, Smart Structures and Materials 2003: Industrial 

and Commercial Applications of Smart Structures Technologies, E. Anderson (editor), Proc. SPIE, Vol. 5054, 

2003. 

[152]Zink, P., Raveh, D., Mavris, D., “Integrated Trim and Structural Design Process for Active Aeroelastic Wing 

Technology,” Journal of Aircraft, Vol. 40, No. 3, pp. 523-531, 2003. 

[153]Chen, P., Sarhaddi, D., Jha, R., Liu, D., Griffin, K., Yurkovich, R., “Variable Stiffness Spar Approach for 

Aircraft Maneuver Enhancement Using ASTROS,” Journal of Aircraft, Vol. 37, No. 5, pp. 865-871, 2004. 

[154]Cooper, J., “Adaptive Stiffness Structures for Air Vehicle Drag Reduction,” Mulitfunctional 

Structures/Integration of Sensors and Antennas, Meeting Proceedings RTO-MP-AVT-141, Neuilly-su-Seine, 

France, pp. 15.1-15.12, 2006. 

[155]Maute, K. Reich, G., “Integrated Multidisciplinary Topology Optimization Approach to Adaptive Wing 

Design,” Journal of Aircraft, Vol. 43, No. 1, pp. 23-32, 2006. 

[156]Ehlers, S., Weisshaar, T., “Static Aeroelastic Control of an Adaptive Lifting Surface,” Journal of Aircraft, Vol. 

30, No. 4, pp. 534-540, 1993. 

[157]Nam, C., Kim, Y., Weisshaar, T., “Optimal Sizing and Placement of Piezo-Actuators for Active Flutter 

Suppression,” Smart Materials and Structures, Vol. 5, pp. 216-224, 1996. 

[158]Cesnik, C., Ortega-Morales, M., Patil, M., “Active Aeroelastic Tailoring of High Aspect Ratio Composite 

Wings,” AIAA Structures, Structural Dynamics, and Materials Conference, Atlanta, GA, April 3-6, 2000. 

[159]Forster, E., Livne, E., “Integrated Structure/Actuation Synthesis of Strain Actuated Devices for Shape 

Control,” AIAA Structures, Structural Dynamics, and Materials Conference, Seattle, WA, April 16-19, 2001. 

[160]Nam, C., Chattopadhyay, A., Kim, Y., “Application of Shape Memory Alloy (SMA) Spars for Aircraft 

Maneuver Enhancement,” In: Davis, L.P. (ed.), Proceedings of SPIE Smart Structures and Materials 2002: 

Smart Structures and Integrated Systems, Davis, L., (editor), San Diego, CA, Vol. 4701, pp. 226-236, July 15, 

2002. 

[161]Kudva, J., “Overview of the DARPA Smart Wing Project,” Journal of Intelligent Material Systems and 

Structures, Vol. 15, pp. 261-267, 2004. 
29

[162]Bartley-Cho, J., Wang, D., Martin, C., Kudva, J., West, M., “Development of High-Rate, Adaptive Trailing 

Edge Control Surface for the Smart Wing Phase 2 Wind Tunnel Model,” Journal of Intelligent Material 

Systems and Structures, Vol. 15, pp. 279-291, 2004. 

[163]Sofla, A., Elzey, D., Wadley, H., “Two-Way Antagonistic Shape Actuation Based on the One-Way Shape 

Memory Effect,” Journal of Intelligent Materials Systems and Structures, Vol. 19, pp. 1017-1027, 2008. 

[164]Philen, M., Phillips, D., Baur, J., “Variable Modulus Materials Based Upon F2MC Reinforced Shape Memory 

Polymers,” AIAA Adaptive Structures Conference, Palm Springs, CA, May 4-7, 2009. 
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Aeroelastic Tailoring of Transport Aircraft Wings: State-of-the-Art and 

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This paper provides a brief overview of the state-of-the-art for aeroelastic tailoring of subsonic transport aircraft and offers 

additional resources on related research efforts. Emphasis is placed on aircraft having straight or aft swept wings. The 

literature covers computational synthesis tools developed for aeroelastic tailoring and numerous design studies focused on 

discovering new methods for passive aeroelastic control. Several new structural and material technologies are presented as 

potential enablers of aeroelastic tailoring, including selectively reinforced materials, functionally graded materials, fiber tow 

steered composite laminates, and various nonconventional structural designs. In addition, smart materials and structures whose 

properties or configurations change in response to external stimuli are presented as potential active approaches to aeroelastic

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Aeroelasticity; Aeronautics; Fixed-Wing Project; Swept wings; Transport aircraft

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