Authors: Heung Soo Kim, Jae Hwan Kim, Li Jie Zhao, Sang Dong Jang, Kyu Young Yun, Sun Kon Lee
Abstract: The application of electroactive polymer devices requires the availability of their
properties at various operating conditions. This in turn necessitates a structure-property relationship
based on an in-depth understanding of the underlying mechanism responsible for their strain-field
response. Cellulose-based Electro-Active Paper (EAPap) has been studied as an attractive Electro
Active Polymer (EAP) material for artificial muscles. The feasibility of EAPap material as an
actuator/sensor application is greatly dependant on piezoelectric effect. In this paper, converse and
di rect piezoelectric ef fect s of Electro-Active Paper materials are studied to characterize
piezoelectric effects of EAPap. All experiments were conducted in an environmental chamber that
can control temperature and humidity.
1507
Authors: Jae Hwan Kim, Nian Gui Wang, Yi Chen, Sun Kon Lee, Chul Ho Yang
Abstract: Electro-Active Paper (EAPap) is attractive for a biomimetic actuator material due to its
merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and
biodegradability. However, the performance of EAPap actuator is so sensitive to humidity that high
humidity is required. We report a robust EAPap actuator that can be activated in room humidity
condition. The EAPap is made by dissolving cellulose fibers into a solution using DMAc solvents,
and made into a sheet by using casting. Thin electrodes are deposited on the cellulose paper to
comprise an EAPap actuator. The fabrication process and the performance evaluation of EAPap are
presented in terms of free displacement with respect to frequency and actuation voltage.
1375
Authors: Sung Ryul Yun, Li Jie Zhao, Nian Gui Wang, Jae Hwan Kim
Abstract: Electro-Active Paper (EAPap) materials based on cellulose are attractive for many
applications because of their low voltage operation, lightweight, dryness, low power consumption,
bio-degradability. The construction of EAPap actuator has been achieved using the cellulose paper
film coated with thin gold electrode layers. This actuator showed a reversible and reproducible
bending movement. In order to improve both force and displacement of this, efforts are made to
construct hybrid EAPap actuators using cellulose paper coated with carbon nanotubes (CNT). To
coat the CNT, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes
(MWCNT) are dispersed in polyaniline (PANI) matrix, and the solution is coated on the EAPap by
using a spin coater. It is expected that the use of CNT can improve the force output by enhancing
the stiffness of the hybrid EAPap actuator. Furthermore, the presence of the PANI may improve the
actuation performance of the EAPap material. The performance of hybrid EAPap actuators is tested
in an environmental chamber in terms of free displacement, blocked force and electrical power
consumption. The performance of hybrid actuators is investigated for bio-mimetic applications.
843
Authors: Heung Soo Kim, Jae Hwan Kim, Seung Bok Choi
Abstract: A modal strain based damage index is proposed to investigate the damage effects of
discrete delaminations in a laminated composite structure. The Fermi-Dirac distribution function is
incorporated with an improved layerwise laminate theory to model smooth transition of the
displacement and the strain fields at the delaminated interfaces. Modal analysis is conducted to
investigate dynamic effects of delamination in a laminated structure and to obtain modal strains. The
damage index is calculated based on fundamental modal strains of laminated structures. The damage
effects of laminated structures are investigated using arbitrary size, number, location and boundary
conditions of discrete delaminations.
925
Authors: Jae Hwan Kim, Sung Ryul Yun, Chun Suk Song
Abstract: Cellulose-based Electro-Active Paper (EAPap) has been studied as an attractive electroactive
polymer material for artificial muscles due to its low cost, availability, lightweight, large
displacement output, low actuation voltage and low power consumption. However, the force output
of EAPap is small since paper is so flexible that the bending stiffness is low. In this paper, the
cellulose based EAPap material is enhanced by using carbon nanotubes with cellulose paper.
Coating of multi-walled carbon nanotubes mixed with polyaniline on EAPap as well as MWNT
dispersion in the paper are tried to enhance the force output of the EAPap. The coating process of
MWNT/PANI on the EAPap and the dispersion of MWNT in the cellulose paper are explained. The
performance of the hybrid EAPap actuators is evaluated in terms of tip displacement, blocking force
and electrical power consumption. The power output and the actuator efficiency are improved.
166
Authors: Heung Soo Kim, Seung Bok Choi, Jae Hwan Kim
Abstract: A dynamic analysis method has been developed to investigate and characterize the effect due to the presence of discrete single and multiple delaminations of composite laminated structures. The Fermi-Dirac distribution function is combined with an improved layerwise laminate theory to model a smooth transition in the displacement and the strain fields of the delaminated interfaces. In modeling piezoelectric composite plates, a coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. Based on the developed model, the effects of discrete delaminations are quantified by comparing transient responses of composite plates and piezoelectric sensor outputs.
375
Authors: Jae Hwan Kim, Woo Chul Jung, Chun Suk Song
Abstract: This paper introduces the concept of remotely-driven smart actuator utilized by
electro-active paper (EAPap). The feature of remotely-driven smart actuator offers unique performance and application capabilities and exploit many of these unique capabilities. Since the microwave-driven actuator does not require carry-on-battery, ultra-lightweight, and distributed micro size actuators can be made. A dipole rectifying antenna (rectenna) array receives the microwave and converts it into a DC power. Recently, cellulose based paper has been came across as an lectroactive paper (EAPap) material so as to be used as artificial muscles for biomimetic insects. Since the power requirement of EAPap is less than the safety limit of microwave power in air, the EAPap actuators can be driven by wireless microwave power. This idea is useful for specific applications that require multifunctional capabilities such as smart skin, ultra-lightweight space structures, micro robots, flapping wing for insect-like flying objects and smart wall paper as well. Current research status along with its issues is addressed including a hybrid actuator of EAPap and conducting polymers that will enhance the performance of the actuator.
1534
Authors: Jae Hwan Kim, Yu Keun Kang, Sung Ryul Yun
Abstract: This paper presents the characterization of Electro-active paper (EAPap). EAPap is a paper that produces large displacement with small force under electrical excitation. EAPap is made with a cellulose paper by constructing thin electrodes on both sides of the paper. When electrical voltage is applied to the electrodes the EAPap produces bending displacement. To be able to apply EAPap in many applications, characterization of EAPap is essential to understand and improve EAPap actuators. The characterization is done in terms of mechanical, electrical and physical tests. Mechanical strain and strength are investigated in sheet level and thermo-mechanical analysis is performed. Electrical resistance and admittance are analyzed to investigate the actuation mechanism. The actuation principle associated with piezoelectric effect is explained. EAPap has merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and low power consumption. The most attractive characteristics of EAPap materials is their application potential for the development of biomimetic systems that are ultra-lightweight, low power, flexible, damage tolerant, noiseless, and agile.
671
Authors: Jae Hwan Kim, Chul Hee Jo
2107
Authors: Jae Hwan Kim, Jae Hong Park
921