The intrusion of unwanted sound is a matter of increasing concern worldwide as growing sound pollution impacts human health, productivity and wellbeing. Lower frequency noise is particularly important, as this is where the human ear is most sensitive. Irritating acoustic intrusion increasingly occurs in buildings, yet sound insulation at low frequencies is challenging and expensive. Meta-materials o er a relatively new approach to achieving sound and vibration isolation. This approach is being used to develop panels with internal resonant structures that are only a few centimetres thick yet strongly interact with acoustic waves. These structures can yield signi cantly greater transmission loss than conventional insulation systems. Numerical models based on networks of single-degree of freedom oscillators were used to understand how the components of the locally resonant structure (LRS) can be manipulated to generate sound transmission loss (STL) performance spectrums. Designs with the desired STL characteristics were then examined in detail and samples were fabricated using industry-standard materials and processes. This paper focuses on the acoustic testing of these LRS samples at low frequencies. Comparisons were made between, numerical predictions and experimental results (small scale (plane wave) to large scale (di use eld) conditions). The highest performing network arrangements combined layers of resonators with multiple resonances to increase system bandwidth. At frequencies below 1 kHz the samples yielded large attenuation gains with peaks of 80dB under normal incidence, and good correspondence to modelling predictions. In di use eld conditions the samples still showed signi cant STL improvements above that of a conventional panel over bandwidths in the order of 300 Hz. The resulting systems have the potential to provide signi cantly higher transmission loss at low frequencies than conventional wall systems of similar size and weight.
Dielectric elastomers (DEs) can theoretically operate at efficiencies greater than that of electromagnetics. This is due to their unique mode of operation which involves charging and discharging a capacitive load at a few kilovolts (typically 1kV-4kV). Efficient recovery of the electrical energy stored in the capacitance of the DE is essential in achieving favourable efficiencies as actuators or generators. This is not a trivial problem because the DE acts as a voltage source with a low capacity and a large output resistance. These properties are not ideal for a power source, and will reduce the performance of any power conditioning circuit utilizing inductors or transformers. This paper briefly explores how circuit parameters affect the performance of a simple inductor circuit used to transfer energy from a DE to another capacitor. These parameters must be taken into account when designing the driving circuitry to maximize performance.
Dielectric elastomer generators (DEG) are variable capacitor power generators that are a highly promising technology
for harvesting energy from environmental sources because they have the ability to work over a wide frequency range
without sacrificing their high energy density or efficiency. DEG can also take on a wide range of configurations, so they
are customizable to the energy source.
A typical generation cycle requires electrical charge to be supplied and removed from the DEG at appropriate times as it
is mechanically deformed. The manner in which the DEG charge state is controlled greatly influences energy
production. The recently developed self-priming circuit can provide this functionality without any active electronics, but
it is not configurable to match the generator and its energy source. In this paper a highly configurable self-priming
circuit is introduced and an analysis of the self-priming DEG cycle is performed to obtain design rules to optimize the
rate at which it can boost its operating voltage. In a case study we compare the performance of an initial prototype selfpriming
circuit with one that has been intentionally optimized. The optimized generator voltage climbed from 30 V up
to 1500 V in 27 cycles, whereas the same generator required 37 cycles when the suboptimal self-priming circuit was
used.
Unlike electromagnetic actuators, Dielectric Elastomer Actuators (DEAs) can exert a static holding force without
consuming a significant amount of power. This is because DEAs are electrostatic actuators where the electric charges
exert a Maxwell stress. A charged DEA stores its electrical energy as potential energy, in a similar way to a capacitor. To
remove or reduce the Maxwell stress, the stored charge with its associated electrical energy must be removed. Current
DEA driver electronics simply dispose of this stored electrical energy. If this energy can be recovered, the efficiency of
DEAs would improve greatly. We present a simple and efficient way of re-using this stored energy by directly
transferring the energy stored in one DEA to another. An energy transfer efficiency of approximately 85% has been
achieved.
The global demand for renewable energy is growing, and ocean waves and wind are renewable energy
sources that can provide large amounts of power. A class of variable capacitor power generators called
Dielectric Elastomer Generators (DEG), show considerable promise for harvesting this energy because they
can be directly coupled to large broadband motions without gearing while maintaining a high energy density,
have few moving parts, and are highly flexible.
At the system level DEG cannot currently realize their full potential for flexibility, simplicity and low mass
because they require rigid and bulky external circuitry. This is because a typical generation cycle requires
high voltage charge to be supplied or drained from the DEG as it is mechanically deformed.
Recently we presented the double Integrated Self-Priming Circuit (ISPC) generator that minimized external
circuitry. This was done by using the inherent capacitance of DEG to store excess energy. The DEG were
electrically configured to form a pair of charge pumps. When the DEG were cyclically deformed, the charge
pumps produced energy and converted it to a higher charge form. In this paper we present the single ISPC
generator that contains just one charge pump. The ability of the new generator to increase its voltage through
the accumulation of generated energy did not compare favourably with that of the double ISPC generator.
However the single ISPC generator can operate in a wider range of operating conditions and the mass of its
external circuitry is 50% that of the double ISPC generator.
Sensing the electrical characteristics of a Dielectric Elastomer Actuator(s) (DEA) during actuation is critical to
improving their accuracy and reliability. We have created a self-sensing system for measuring the equivalent series
resistance of the electrodes, leakage current through the equivalent parallel resistance of the dielectric membrane, and the
capacitance of the DEA whilst it is being actuated. This system uses Pulse Width Modulation (PWM) to simultaneously
generate an actuation voltage and a periodic oscillation that enables the electrical characteristics of the DEA to be
sensed. This system has been specifically targeted towards low-power, portable devices. In this paper we experimentally
validate the self-sensing approach, and present a simple demonstration of closed loop control of the area of an expanding
dot DEA using capacitance feedback.
Dielectric Elastomer Generator(s) (DEG) have many unique properties that give them advantages over
conventional electromagnetic generators. These include the ability to effectively generate power from slow and
irregular motions, low cost, relatively large energy density, and a soft and flexible nature. For DEG to generate
usable electrical energy circuits for charging (or priming) the stretched DEG and regulating the generated
energy when relaxed are required. Most prior art has focused on the priming challenge, and there is currently
very little work into developing circuits that address design issues for extracting the electrical energy and
converting it into a usable form such as low DC voltages (~10 V) for small batteries or AC mains voltage (~100
V).
This paper provides a brief introduction to the problems of regulating the energy generated by DEG. A buck
converter and a charge pump are common DC-DC step-down circuits and are used as case studies to explore the
design issues inherent in converting the high voltage energy into a form suitable for charging a battery. Buck
converters are efficient and reliable but also heavy and bulky, making them suitable for large scale power
generation. The smaller and simpler charge pump, though a less effective energy harvester, is better for small
and discrete power generation. Future development in miniature DE fabrication is expected to reduce the high
operational voltages, simplifying the design of these circuits.
Life shows us that the distribution of intelligence throughout flexible muscular networks is a highly successful solution
to a wide range of challenges, for example: human hearts, octopi, or even starfish. Recreating this success in engineered
systems requires soft actuator technologies with embedded sensing and intelligence. Dielectric Elastomer Actuator(s)
(DEA) are promising due to their large stresses and strains, as well as quiet flexible multimodal operation. Recently
dielectric elastomer devices were presented with built in sensor, driver, and logic capability enabled by a new concept
called the Dielectric Elastomer Switch(es) (DES). DES use electrode piezoresistivity to control the charge on DEA and
enable the distribution of intelligence throughout a DEA device.
In this paper we advance the capabilities of DES further to form volatile memory elements. A set reset flip-flop with
inverted reset line was developed based on DES and DEA. With a 3200V supply the flip-flop behaved appropriately and
demonstrated the creation of dielectric elastomer memory capable of changing state in response to 1 second long set and
reset pulses. This memory opens up applications such as oscillator, de-bounce, timing, and sequential logic circuits; all of
which could be distributed throughout biomimetic actuator arrays.
Future work will include miniaturisation to improve response speed, implementation into more complex circuits, and
investigation of longer lasting and more sensitive switching materials.
Dielectric Elastomer Generator(s) (DEG), are essentially variable capacitor power generators formed by hyper-elastic
dielectric materials sandwiched between flexible electrodes.
Electrical energy can be produced from a stretched, charged DEG by relaxing the mechanical deformation whilst
maintaining the amount of charge on its electrodes. This increases the distance between opposite charges and packs likecharges
more densely, increasing the amount of electrical energy. DEG show promise for harvesting energy from
environmental sources such as wind and ocean waves. DEG can undergo large inhomogeneous deformations and
electric fields during operation, meaning it can be difficult to experimentally determine optimal designs. Also, the circuit
that is used for harnessing DEG energy influences the DEG output by controlling the amount of charge on the DEG.
In this paper an integrated DEG model was developed where an ABAQUS finite element model is used to model the
DEG and data from this model is input to a system level LT-Spice circuit simulation. As a case-study, the model was
used as a design tool for analysing a diaphragm DEG connected to a self-priming circuit. That is, a circuit capable of
overcoming electrical losses by using some of the DEG energy to boost the charge in the system. Our ABAQUS model
was experimentally validated to predict the varying capacitance of a diaphragm DEG deformed inhomogeneously to
within 6% error.
Arrays of actuators are ubiquitous in nature for manipulation, pumping and propulsion. Often these arrays are
coordinated in a multi-level fashion with distributed sensing and feedback manipulated by higher level controllers. In
this paper we present a biologically inspired multi-level control strategy and apply it to control an array of Dielectric
Elastomer Actuators (DEA). A test array was designed consisting of three DEA arranged to tilt a set of rails on which a
ball rolls. At the local level the DEA were controlled using capacitive self-sensing state machines that switched the
actuator off and on when capacitive thresholds were exceeded, resulting in the steady rolling of the ball around the rails.
By varying the voltage of the actuators in the on state, it was possible to control the speed of the ball to match a set point.
A simple integral derivative controller was used to do this and an observer law was formulated to track the speed of the
ball.
The array demonstrated the ability to self start, roll the ball in either direction, and run at a range of speeds determined by
the maximum applied voltage. The integral derivative controller successfully tracked a square wave set point. Whilst the
test application could have been controlled with a classic centralised controller, the real benefit of the multi-level strategy
becomes apparent when applied to larger arrays and biomimetic applications that are ideal for DEA. Three such
applications are discussed; a robotic heart, a peristaltic pump and a ctenophore inspired propulsion array.
Dielectric breakdown often leads to catastrophic failure in Dielectric Elastomer Actuator(s) (DEA). The resultant
damage to the dielectric membrane renders the DEA useless for future actuation, and in extreme cases the sudden
discharge of energy during breakdown can present a serious fire risk. The breakdown strength of DEA however is
heavily dependent on the presence of microscopic defects in the membrane giving its overall breakdown strength
inherent variability. The practical consequence is that DEA normally have to be operated far below their maximum
performance in order to achieve consistent reliability.
Predicting when DEA are about to suffer breakdown based on feedback will enable significant increase in effective DEA
performance without sacrificing reliability. It has been previously suggested that changes in the leakage current can be a
harbinger of dielectric breakdown; leakage current exhibits a sharp increase during breakdown. In this paper the
relationship between electric field and leakage current is investigated for simple VHB4905-based DEA. Particular
emphasis is placed on the behaviour of leakage current leading up to and during breakdown conditions. For a sample size
of nine expanding dot DEA, the DEA that failed at electric fields below the maximum tested exhibited noticeably higher
nominal power dissipation and a higher frequency of partial discharge events than the DEA that did not breakdown
during testing. This effect could easily be seen at electric fields well below that at which the worst performing DEA
failed.
Human intention recognition is becoming a key part of powered prosthetics research. With the advent of smart
materials, the usefulness of powered prosthetics has increased. Correspondingly, there is a greater need for
control technology. Electromyography (EMG) has previously been used to control myoelectric hands; however
the approach to electrode placement has been speculative at best.
Carpi, Raspopovic and De Rossi have shown that dielectric elastomer actuators (DEAs) can be controlled by a
variety of human electrophysiological signals, including EMG. To control a DEA device with multiple degrees
of freedom using EMG, multiple electrode sites are required. This paper presents an approach to control an array
of DEAs using a series of electrodes and an optimized electrode data filtering scheme to maximize classification
accuracy when differentiating between hand grasps.
A silicon mould of a human forearm was created with an array of electrodes embedded within it. Data from each
electrode site was recorded using the Universal Electrophysiological Mapping (UnEmap) system developed at
the University of Auckland Bioengineering Institute for the amplification and filtering of multiple biopotential
signals.
The recorded data was then processed off-line, in order to calculate spatial gradients; this would determine
which electrode sites would give the best bipolar readings. The spatial gradients were then compared to each
other in order to find the optimal electrode sites. Several points in the extensor compartment of the forearm were
found to be useful in recognizing grasping, while several points in the flexor compartment of the forearm were
found to be useful in differentiating between grasps.
The excellent overall performance and compliant nature of Dielectric Elastomer Actuators (DEAs) make them ideal
candidates for artificial muscles. Natural muscle however is much more than just an actuator, it provides position
feedback to the brain that is essential for the body to maintain balance and correct posture. If DEAs are to truly earn the
moniker of "artificial muscles" they need to be able to reproduce, if not improve on, this functionality.
Self-sensing DEAs are the ideal solution to this problem. This paper presents a system by which the capacitance of a
DEA can be sensed while it is being actuated and used for feedback control. This system has been strongly influenced by
the desire for portability i.e. designed for use in a battery operated microcontroller based system. It is capable of
controlling multiple independent DEAs using a single high voltage power supply. These features are important
developments for artificial muscle devices where accuracy and low mass are important e.g. a prosthetic hand or force-feedback
surgical tools.
A numerical model of the electrical behaviour of the DEA that incorporates arbitrary leakage currents and the impact of
arbitrary variable capacitance has been created to model a DEA system. A robust capacitive self-sensing method that
uses a slew-rate controlled Pulse Width Modulation (PWM) signal and compensates for the effects of leakage current
and variable capacitance is presented. The numerical model is then used to compare the performance of this new method
with an earlier method previously published by the authors.
Ctenophores or "comb jellies" are small sea creatures that propel themselves with rows of ciliated bending actuators or
'paddles'. In some species the actuators are coordinated via mechano-sensitivity; the physical contact of one paddle
triggers the motion of the next resulting in a wave of activation along the row. We seek to replicate this coordination
with an array of capacitive self-sensing Dielectric Elastomer Minimum Energy Structure(s) (DEMES) bending actuators.
For simplicity we focused on a conveyor application in air where four DEMES were used to roll cylindrical loads along
some rails. Such a system can automatically adjust to changing load dynamics and requires very little computational
overhead to achieve coordination.
We used a finite element modelling approach for DEMES development. The model used a hybrid Arruda-Boyce strain
energy function augmented with an electrostatic energy density term to describe the DEA behaviour. This allowed the
use of computationally efficient membrane elements giving simulation times of approximately 15 minutes and thus rapid
design development. Criteria addressing failure modes, the equilibrium state, and stroke of the actuators were developed.
The model had difficulty in capturing torsional instability in the frame thus design for this was conducted
experimentally.
The array was built and successfully propelled teflon and brass rollers up an incline. Noise in the capacitive sensor
limited the sensitivity of the actuators however with PCB circuit fabrication this problem should be solved.
We describe a low profile and lightweight membrane rotary motor based on the dielectric elastomer actuator (DEA). In
this motor phased actuation of electroded sectors of the motor membrane imparts orbital motion to a central gear that
meshes with the rotor.
Two motors were fabricated: a three phase and four phase with three electroded sectors (120°/sector) and four sectors
(90°/sector) respectively. Square segments of 3M VHB4905 tape were stretched equibiaxially to 16 times their original
area and each was attached to a rigid circular frame. Electroded sectors were actuated with square wave voltages up to
2.5kV. Torque/power characteristics were measured. Contactless orbiter displacements, measured with the rotor
removed, were compared with simulation data calculated using a finite element model.
A measured specific power of approximately 8mW/g (based on the DEA membrane weight), on one motor compares
well with another motor technology. When the mass of the frame was included a peak specific power of 0.022mW/g was
calculated. We expect that motor performance can be substantially improved by using a multilayer DEA configuration,
enabling the delivery of direct drive high torques at low speeds for a range of applications.
The motor is inherently scalable, flexible, flat, silent in operation, amenable to deposition-based manufacturing
approaches, and uses relatively inexpensive materials.
Dielectric Elastomer (DE) transducers are essentially compliant capacitors fabricated from highly flexible materials that
can be used as sensors, actuators and generators. The energy density of DE is proportional to their dielectric constant
(εr), therefore an understanding of the dielectric constant and how it can be influenced by the stretch state of the material is required to predict or optimize DE device behavior. DE often operate in a stretched state. Wissler and Mazza, Kofod
et al., and Choi et al. all measured an εr of approximately 4.7 for virgin VHB, but their results for prestretched DE
showed that the dielectric constant decayed to varying degrees. Ma and Cross measured a dielectric constant of 6 for the
same material with no mention of prestretch. In an attempt to resolve this discrepancy, εr measurements were
performed on parallel plate capacitors consisting of virgin and stretched VHB4905 tape electroded with either gold
sputtered coatings or Nyogel 756G carbon grease. For an unstretched VHB tape, an εr of 4.5 was measured with both
electrode types, but the measured εr of equibiaxially stretched carbon specimens was lower by between 10 to 15%. The
dielectric constant of VHB under high fields was assessed using blocked force measurements from a dielectric elastomer
actuator. Dielectric constants ranging from 4.6-6 for stretched VHB were calculated using the blocked force tests.
Figure of merits for DE generators and actuators that incorporate their nonlinear behavior were used to assess the
sensitivity of these systems to the dielectric constant.
Dielectric elastomer actuators (DEAs) are a promising artificial muscle technology that will enable new kinds of
prostheses and wearable rehabilitation devices. DEAs are driven by electric fields in the MV/m range and the dielectric
elastomer itself is typically 30μm in thickness or more. Large operating voltages, in the order of several kilovolts, are
then required to produce useful strains and these large voltages and the resulting electric fields could potentially pose
problems when DEAs are used in close proximity to the human body. The fringing electric fields of a DEA in close
association with the skin were modelled using finite element methods. The model was verified against a known analytic
solution describing the electric field surrounding a capacitor in air. The agreement between the two is good, as the
difference is less than 10% unless within 4.5mm of the DEA's lateral edges. As expected, it was found that for a DEA
constructed with thinner dielectric layers, the fringe field strength dropped in direct proportion to the reduction in applied
voltage, despite the internal field being maintained at the same level. More interestingly, modelling the electric field
around stacked DEAs showed that for an even number of layers the electric field is an order of magnitude less than for
an odd number of layers, due to the cancelling of opposing electric fields.
The future of Dielectric Elastomer Actuator (DEA) technology lies in miniaturizing individual elements and utilizing
them in array configurations, thereby increasing system fault tolerance and reducing operating voltages. An important
direction of DEA research therefore is real-time closed loop control of arrays of DEAs, particularly where multiple
degrees-of-freedom are desirable.
As the number of degrees-of-freedom increases a distributed control system offers a number of advantages with respect
to speed and efficiency. A low bandwidth digital control method for DEA devices is presented in this paper. Pulse Width
Modulation (PWM) is used as the basis for a current controlled DEA system that allows multiple degrees-of-freedom to
be controlled independently and in parallel using a single power supply set to a fixed voltage. The amplitude and the
duty cycle of the PWM signal control the current flow through a high speed, high voltage opto-coupler connected in
series with a DEA, enabling continuous control of both the output displacement and speed. Controlling the current in
real-time results in a system approaching a stable and robust constant charge system.
Closed loop control is achieved by measuring the rate of change of the voltage across the DEA in response to a step
change in the current input generated by the control signal. This enables the capacitance to be calculated, which in
combination with the voltage difference between the electrodes and the initial dimensions, enables the charge, strain state
and Maxwell pressure to be inferred. Future developments include integrating feedback information directly with the
control signal, leaving the controller to coordinate rather than control individual degrees-of-freedom.
This paper presents an experimentally validated, nonlinear finite element model capable of predicting the blocked force
produced by Dielectric Elastomer Minimum Energy Structure (DEMES) bending actuators. DEMES consist of pre-stretched
dielectric elastomer (DE) films bonded to thin frames, the complex collapse of which can produce useful
bending actuation. Key advantages of DEMES include the ability to be fabricated in-plane, and the elimination of bulky
pre-stretch supports which are often found in other DE devices.
Triangular DEMES with 3 different pre-stretch ratios were fabricated. Six DEMES at each stretch ratio combination
were built to quantify experimental scatter which was significant due to the highly sensitive nature of the erect DEMES
equilibrium point. The best actuators produced approximately 10mN blocked force at 2500V.
We integrate an Arruda-Boyce model incorporating viscoelastic effects with the Proney series to describe the stress-strain
response of the elastomer, and a Neo-Hookean model to describe the frame. Maxwell pressure was simulated using
a constant thickness approximation and an isotropic membrane permittivity was calculated for the stress state of the
DEMES membrane.
Experimental data was compared with the model and gave reasonable correlation. The model tended to underestimate the
blocked force due to a constant thickness assumption during the application of Maxwell stress. The spread due to
dielectric constant variance is also presented and compared with the spread of experimental scatter in the results.
Our work focuses on a contractile dielectric elastomer actuator (DEA) based on the McKibben pneumatic muscle
concept. A coupled-field ABAQUS (Hibbit, Karlsson & Sorensen, Inc., USA) FEA model has been developed where
the constraints of the orthotropic fibre weave and end caps of this actuator design are included. The implementation of
the Maxwell pressure model that couples electrical inputs to mechanical loads using the ABAQUS user subroutine
DLOAD is the focus of this paper. Our model was used to perform a study of actuator design parameters including the
fibre weave angle, dielectric thickness, and the DEA's length. At a fibre angle of 45° relative to the longitudinal axis, no
axial deformation was predicted by our model. A weave angle above this resulted in an axial expansion during
actuation, whereas axial compression occurred if the fibre angle was less than 45°. For instance, at a fibre angle of 30°
with respect to the longitudinal axis, this model predicted a compressive axial strain of 4.5% before mechanical failure
for an actuator with an outer radius of 2mm, wall thickness of 0.5mm, and length of 20mm.
This paper presents a method for creating a smart Dielectric Elastomer Actuator (DEA) with an integrated extension
sensor based on resistance and voltage measurement. Such a sensor can reduce cost, complexity, and weight compared to
external sensor solutions when used in applications where external sensing is difficult or costly, such as Micro-Electro-
Mechanical Systems (MEMS). The DEAs developed for integrated feedback are 20mm by 70mm and 30 &mgr;m thick
double layer silicone-dielectric actuators with reinforcing silicone ribs. Loose-carbon-powder electrodes produced the
best electrical and mechanical characteristics out of several possibilities tried.
Electrically isolated circuits were used to measure electrode resistance and driving voltage. These parameters were then
related to experiment using a model to predict DEA length. An offline regression method was used to fit the model to
within 2% of the full sensor range and the results were verified experimentally. The sensor feedback inaccuracy
immediately after a position step disturbance was shown to be around 20% of the full sensor range. This improved over 5
seconds to less than 5% as the transient creep effects in the silicone membrane that introduced the initial inaccuracy
decayed. Long term creep reduced the accuracy of the model, necessitating periodic retraining of the sensor. Overall the
sensor-estimated extension shows a very good qualitative or 'shape' match with the actual extension in the system.
The active suppression of elastic buckling instability has the
potential to significantly increase the effective strength of
thin-wall structures. Despite all the interest in smart
structures, the active suppression of buckling has received
comparatively little attention. This paper addresses the effects
of embedded actuation on the compression buckling strength of
laminated composite plates through analysis and simulation.
Numerical models are formulated that include the influence of
essential features such as sensor uncertainty and noise, actuator
saturation and control architecture on the buckling process.
Silicon-based strain sensors and diffuse laser distance sensors
are both considered for use in the detection of incipient buckling
behavior due to their increased sensitivity. Actuation is provided
by paired distributions of piezo-electric material incorporated
into both sides of the laminate. Optimal controllers are designed
to command the structure to deform in ways that interfere with the
development of buckling mode shapes. Commercial software packages
are used to solve the resulting non-linear equations, and some of
the tradeoffs are enumerated. Overall, the results show that
active buckling control can considerably enhance resistance to
instability under compressive loads. These buckling load
predictions demonstrate the viability of optimal control and
piezo-electric actuation for implementing active buckling control.
Due to the importance of early detection, the relative
effectiveness of active buckling control is shown to be strongly
dependent on the performance of the sensing scheme, as well as on
the characteristics of the structure.
Elastic instability is often the limiting factor in the design of thin-walled structural components, accentuated by the imperfections typical of real structures. Smart structures have the potential to use piezoelectric or shape memory materials to actively generate stabilizing internal forces. These smart materials can be made into in-plane actuator layers and added to both surfaces of the structure to generate bending couples. In spite of the interest in smart structures, the potential of active tailoring and control of buckling has received scant attention. This paper examines the capacity of such actuator layer pairs to change the compression buckling loads of thin structures by interfering with the development of incipient buckling mode shapes. Amo del is formulated that idealizes the actuator layers as nonlinear springs that impede or promote out-of-plane bending until a saturation bending moment is reached. Acommercial finite element software package is used to solve the resulting non-linear equilibrium equations for a selection of materials, geometries, and structure sizes, to investigate the sensitivities of the buckling suppression effect. Overall the results show that smart laminates can actively interact with their instabilities and minimize the effect of imperfections. Although substantial gains in buckling load can be achieved in some cases, the relative effectiveness of active stabilization control is strongly dependent on the characteristics of structure, sensors and actuators.
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