Polyurethane shape memory polymers (PU-SMPs) are active materials that can be transformed into complex shapes with
the ability to recover their original shape even after undergoing large deformations. Because of their light weight,
large recoverability, low cost, and high compliance, SMPs can be potentially employed as actuators, MEMS devices,
temperature sensors, and damping elements to name a few. One of the key challenges in implementing SMPs is
the response time which is limited by the method of heating and cooling and the material. Unlike shape memory alloys,
SMPs can be activated by multiple stimuli including lasers, resistive heating, electric fields, and magnetic fields.
While these methods may provide an efficient way of heating the SMP, they rely on the slow process of passive
conduction for cooling. In this paper, a self regulating SMP (SR-SMP) composite is introduced, whereby a novel
heating and cooling system consisting of embedded silica capillary tubes in the SMP (DiAPLEX® MP4510: SMP
Technologies, Inc.) has been developed. The tubes are used to pump hot/cold fluid through the SMP membrane and
hence provide a local temperature source. In order to show the effectiveness and efficiency of the mechanism, the
thermomechanical response of the SR-SMP is compared experimentally to a SMP with "conventional" i.e. global
heating and cooling mechanisms. It is shown that the SR-SMP has a faster thermomechanical response. It has been
demonstrated previously that soft SMPs can be controlled by an electric field while in the rubbery phase, thus taking
advantage of the Maxwell stress or electrostatic stress effect. Thermomechanical characterization of PU-SMPs is
described for different weight percentages of resin (Diphenylmethane-4, 4'-diisocyanate) and hardener (1,4-Butanediol).
Varying the percent hardener reduced the effective cross-link density of the polymer and hence the thermomechanical
properties. The electromechanical response of pure SMP and SR-SMP is predicted numerically. The numerical
computation indicates that the softer SMPs (resin:hardener = 5:4, 8:7, and 9:8) could be used as electroactive polymers.
In this paper, a finite element model is used to describe the inhomogeneous deformations of dielectric elastomers (DE).
In our previous work, inhomogeneous deformations of the DE with simple boundary conditions represented by a system
of highly nonlinear coupled differential equations (ordinary and partial) were solved using numerical approaches [1-3].
To solve for the electromechanical response for complex shapes (asymmetric), nonuniform loading, and complex
boundary conditions a finite element scheme is required. This paper describes a finite element implementation of the DE
material model proposed in our previous work in a commercial FE code (ABAQUS 6.8-1, PAWTUCKET, R.I, USA).
The total stress is postulated as the summation of the elastic stress tensor and the Maxwell stress tensor, or more
generally the electrostatic stress tensor. The finite element model is verified by analytical solutions and experimental
results for planar membrane extensions subject to mechanical loads and an electric field: (i) equibiaxial extension and (ii)
generalized biaxial extension. Specifically, the analytical solutions for equibiaxial extension of the DE is obtained by
combining a modified large deformation membrane theory that accounts for the electromechanical coupling effect in
actuation commonly referred to as the Maxwell stress . A Mooney-Rivlin strain energy function is employed to
describe the constitutive stress strain behavior of the DE. For the finite element implementation, the constitutive
relationships from our previously proposed mathematical model  are implemented into the finite element code.
Experimentally, a 250% equibiaxially prestretched DE sample is attached to a rigid joint frame and inhomogeneous
deformations of the reconfigurable DE are observed with respect to mechanical loads and an applied electric field. The
computational result for the reconfigurable DE is compared with the test result to validate the accuracy and robustness of
the finite element model. The active membrane is being investigated to simulate the deformation response of the
plagiopatagium of bat wing skins for a micro-aerial vehicle.
Dielectric elastomer (DE) membranes are one of the most promising transducers for developing in situ sensors for the
vasculature. It is widely accepted that diseased arteries at various stages have a unique constitutive response. This
means that the output of an in situ artery sensor would have distinct profiles corresponding to various stages of unhealth.
An in situ sensor can potentially allow access to information about the mechanical state of the artery that is not currently
available. Furthermore, the potential to combine the functions of providing structural support (stent) and monitoring the
mechanical state (sensor) is truly unique (multifunctionality). Traditional sensors such as strain gages and piezoelectric sensors are stiff and fail at low strains (<1%) whereas some dielectric elastomers are viable at strains up to and even
surpassing 100%. Investigating the electromechanical response of a deformable tube sensor sandwiched between a
pulsating pressure source and a nonlinear elastic distensible thick wall has not been attempted before now. The
successful development of a multiphysics model that correlates the electrical output of a pulsatile membrane sensor to its
state of strain would be a significant breakthrough in medical diagnostics. The artery is modeled numerically and
represented theoretically as a fiber reinforced tubular membrane subject to a pulsating pressure signal. In this paper, the
fundamental mechanics associated with electromechanical coupling during dynamic finite deformations of DEs is
derived. A continuum model for the dynamic response of tubular dielectric elastomer membranes configured for sensing
In this paper, a self-sensing McKibben actuator using dielectric elastomer sensors is presented. Fiber-reinforced
cylindrical actuators offer one potential solution to the low-force output problem that plagues many artificial muscle
actuators. Placing a cylindrical dielectric elastomer sensor in direct contact with the inner surface of the McKibben
actuator facilitates in situ monitoring of actuator strains and loads. The deformation of the McKibben actuator and hence
the cylindrical dielectric elastomer sensor results in a change in the electrical signal read from the electroded surfaces of
the dielectric elastomer. In this paper, we present a model for predicting the response of fiber reinforced cylindrical
constructs (McKibben actuators) that are actuated by an inflation pressure, which is used to support an axial load. The
model is based on Adkins and Rivlin's large deformation model for the inflation and contraction of tubes reinforced with
inextensible fibers. In this model, the McKibben actuator is considered as a surface of revolution since the initially near
cylindrical shape is nearly always compromised during mechanical loading. A series of experiments measuring the force
versus contraction behavior of the actuators are used to validate the numerical model. The material constants for an
Ogden model were determined by uni-axial extension of cylindrical samples. A comparison of the numerical and
experimental results shows that the correlation is good. The model enables a number of key analyses such as the effect
of the braid angle and the tension generated in the fibers.