The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Heung Soo Kim - One of the best experts on this subject based on the ideXlab platform.
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In-Plane Strain of electro-active paper under electric fields
Sensors and Actuators A: Physical, 2007Co-Authors: Jae-hwan Kim, Woochul Jung, Heung Soo KimAbstract:Electro-active papers (EAPap) made with cellulose have been known as a biomimetic actuator material according to their merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. This out-of-Plane bending deformation is useful for achieving flapping wings, micro-insect robots, and smart wallpapers. On the other hand, in-Plane Strains, such as extension and contraction of EAPap materials are also promising for artificial muscle applications since the Young's modulus of EAPap materials is large. This paper first reports the experimental investigation of the in-Plane Strain of EAPap materials in the presence of electric fields. The EAPap samples preparation and the in-Plane Strain measurement system are explained. The test results are shown in terms of electric field, frequency and the orientation of the samples. The power consumption and the Strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap materials, this in-Plane Strain may be useful for artificial muscle applications. © 2007 Elsevier B.V. All rights reserved.
Woochul Jung - One of the best experts on this subject based on the ideXlab platform.
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In-Plane Strain of electro-active paper under electric fields
Sensors and Actuators A-physical, 2007Co-Authors: Woochul JungAbstract:Electro-active papers (EAPap) made with cellulose have been known as a biomimetic actuator material according to their merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. This out-of-Plane bending deformation is useful for achieving flapping wings, micro-insect robots, and smart wallpapers. On the other hand, in-Plane Strains, such as extension and contraction of EAPap materials are also promising for artificial muscle applications since the Young's modulus of EAPap materials is large. This paper first reports the experimental investigation of the in-Plane Strain of EAPap materials in the presence of electric fields. The EAPap samples preparation and the in-Plane Strain measurement system are explained. The test results are shown in terms of electric field, frequency and the orientation of the samples. The power consumption and the Strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap materials, this in-Plane Strain may be useful for artificial muscle applications.
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In-Plane Strain of electro-active paper under electric fields
Sensors and Actuators A: Physical, 2007Co-Authors: Jae-hwan Kim, Woochul Jung, Heung Soo KimAbstract:Electro-active papers (EAPap) made with cellulose have been known as a biomimetic actuator material according to their merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. This out-of-Plane bending deformation is useful for achieving flapping wings, micro-insect robots, and smart wallpapers. On the other hand, in-Plane Strains, such as extension and contraction of EAPap materials are also promising for artificial muscle applications since the Young's modulus of EAPap materials is large. This paper first reports the experimental investigation of the in-Plane Strain of EAPap materials in the presence of electric fields. The EAPap samples preparation and the in-Plane Strain measurement system are explained. The test results are shown in terms of electric field, frequency and the orientation of the samples. The power consumption and the Strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap materials, this in-Plane Strain may be useful for artificial muscle applications. © 2007 Elsevier B.V. All rights reserved.
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In-Plane Strain capability of cellulose EAPap material
Smart Structures and Materials 2006: Active Materials: Behavior and Mechanics, 2006Co-Authors: Woochul Jung, Yukeun Kang, Sang-dong JangAbstract:Electro-Active Paper (EAPap) has been interested in due to its merits in terms of lightweight, dry condition, large displacement output, low actuation voltage, low power consumption and biodegradability. EAPap actuator has been made with cellulose material. Cellulose fibers are dissolved into a solution and extruded in a sheet form, and thin gold electrodes are made on it. This out-of-Plane bending deformation is useful for achieving flapping wings, micro-insect robots, and smart wall papers. On the other hand, in-Plane Strains, such as extension and contraction of EAPap materials are also promising for artificial muscle applications since the Young's modulus of EAPap materials is large. Therefore, we intended to investigate the in-Plane Strain of EAPap materials in the presence of electric fields. The EAPap samples preparation and the in-Plane Strain measurement are explained. The test results are shown in terms of electric field, frequency and the orientation of the samples. The power consumption and the Strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap materials, this in-Plane Strain may be useful for artificial muscle applications.
Dariusz Wanatowski - One of the best experts on this subject based on the ideXlab platform.
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Drained instability of sand in Plane Strain
Canadian Geotechnical Journal, 2010Co-Authors: Dariusz Wanatowski, Wai Lay Lokew.l. LokeAbstract:Flowslide or failure of loose granular soil slopes is often explained using liquefaction or instability data obtained from undrained triaxial tests. However, under static loading conditions, the assumption of an undrained condition is not realistic for sand, particularly clean sand. Case studies have indicated that instability of granular soil can occur under essentially drained conditions (e.g., the Wachusett Dam failure in 1907). Laboratory studies on Changi sand by Chu et al. in 2003 have shown that sand can become unstable under completely drained conditions. However, these studies were carried out under axisymmetric conditions and thus, cannot be applied directly to the analysis of slope failures. In this paper, experimental data obtained from Plane-Strain tests are presented to study the instability behaviour of loose and dense sand under Plane-Strain conditions. Based on these test data, the conditions for the occurrence of drained instability in Plane Strain are established. Using the modified sta...
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Instability Conditions of Loose Sand in Plane Strain
Journal of Geotechnical and Geoenvironmental Engineering, 2008Co-Authors: Dariusz WanatowskiAbstract:When a loose sand specimen is loaded under an undrained condition, it may become unstable. The instability conditions may be specified by an instability line determined using undrained tests. However, the instability behavior of sand has seldom been studied under Plane-Strain conditions. Experimental data obtained under both triaxial and Plane-Strain conditions are presented in this paper to define the instability conditions of loose sand under Plane-Strain conditions. Using the state parameter, a unified relationship can be established between the normalized slope of instability line and the state parameters for both axisymmetric and Plane-Strain conditions. Using this relationship, the instability conditions established under axisymmetric conditions can also be used for Plane-Strain conditions.
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Undrained behaviour of Changi sand in triaxial and Plane-Strain compression
Geomechanics and Geoengineering, 2007Co-Authors: Dariusz WanatowskiAbstract:Many geotechnical problems are under Plane-Strain conditions. However, geotechnical designs still rely largely on testing data obtained under axisymmetric conditions. Therefore a good understanding of the similarities and differences between the strength and deformation behaviours of soil under Plane-Strain and axisymmetric conditions is important. Experimental data obtained from drained triaxial and Plane-Strain tests on very loose and medium dense sand are presented in this paper. The strength and deformation characteristics of the sand under Plane-Strain conditions are studied and compared with those under axisymmetric conditions. The results show that the failure envelope on the Plane under Plane-Strain conditions is below that under axisymmetric conditions, although the friction angle under Plane-Strain conditions is higher than that under axisymmetric conditions. The critical state line and the stress–dilatancy relationship under Plane-Strain conditions are also different from those under axisymmetr...
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static liquefaction of sand in Plane Strain
Canadian Geotechnical Journal, 2007Co-Authors: Dariusz WanatowskiAbstract:Experimental results on the static liquefaction behaviour of sand under Plane-Strain conditions are presented in this paper. Undrained tests on very loose sand under both Plane-Strain and axisymmetric conditions were conducted and the results compared. The test data show that the undrained behaviour of sand under Plane Strain is similar to that under axisymmetric conditions. However, the critical-state line (CSL) on both the q–p′ and the e–p′ Planes determined under Plane-Strain conditions is different from that under axisymmetric conditions. The slope of the CSL is different as a result of the influence of the intermediate principal stress. The state parameter (ψ), which is measured with reference to the CSL in the e – log p′ Plane, is also different: the ψ value for Plane Strain is about 0.05 less than that for axisymmetric conditions for the sand tested. The instability behaviour of very loose sand under undrained Plane-Strain conditions is also studied. Based on the testing data, a unique relationship...
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Stress-Strain Behavior of a Granular Fill Measured by a New Plane-Strain Apparatus
Geotechnical Testing Journal, 2006Co-Authors: Dariusz WanatowskiAbstract:In this paper a new Plane-Strain apparatus is described. The main feature of the Plane-Strain apparatus is that the intermediate principal stress can be measured by four submersible pressure transducers. Experimental data obtained from drained tests on very loose to medium dense sand are presented. The strength and deformation behavior of the sand under Plane-Strain conditions and shear band formation are studied. The results show that the failure envelope obtained from Plane-Strain tests is lower than that from triaxial tests. However, in terms of friction angle, the value obtained from Plane-Strain tests is higher than that from triaxial tests. The critical state line obtained under Plane-Strain conditions is also different from that under axisymmetric conditions. Under Plane-Strain conditions, shear bands occur for medium loose to dense specimens. However, no visible shear bands are observed for very loose specimens. This is consistent with the study reported by Han and Vardoulakis (1991) but different from that by Finno et al. (1996, 1997).
Jae-hwan Kim - One of the best experts on this subject based on the ideXlab platform.
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In-Plane Strain of electro-active paper under electric fields
Sensors and Actuators A: Physical, 2007Co-Authors: Jae-hwan Kim, Woochul Jung, Heung Soo KimAbstract:Electro-active papers (EAPap) made with cellulose have been known as a biomimetic actuator material according to their merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. This out-of-Plane bending deformation is useful for achieving flapping wings, micro-insect robots, and smart wallpapers. On the other hand, in-Plane Strains, such as extension and contraction of EAPap materials are also promising for artificial muscle applications since the Young's modulus of EAPap materials is large. This paper first reports the experimental investigation of the in-Plane Strain of EAPap materials in the presence of electric fields. The EAPap samples preparation and the in-Plane Strain measurement system are explained. The test results are shown in terms of electric field, frequency and the orientation of the samples. The power consumption and the Strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap materials, this in-Plane Strain may be useful for artificial muscle applications. © 2007 Elsevier B.V. All rights reserved.
Viggo Tvergaard - One of the best experts on this subject based on the ideXlab platform.
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effects of texture on shear band formation in Plane Strain tension compression and bending
International Journal of Plasticity, 2007Co-Authors: Mitsutoshi Kuroda, Viggo TvergaardAbstract:Abstract In this study, effects of typical texture components observed in rolled aluminum alloy sheets on shear band formation in Plane Strain tension/compression and bending are systematically studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain is characterized in terms of an elastic–viscoplastic continuum slip constitutive relation. First, a simple model analysis in which the shear band is assumed to occur in a weaker thin slice of material is performed. From this simple model analysis, two important quantities regarding shear band formation are obtained: i.e. the critical Strain at the onset of shear banding and the corresponding orientation of shear band. Second, the shear band development in Plane Strain tension/compression is analyzed by the finite element method. Predictability of the finite element analysis is compared to that of the simple model analysis. Third, shear band developments in Plane Strain pure bending of a sheet specimen with the typical textures are studied. Regions near the surfaces in a bent sheet specimen are approximately subjected to Plane Strain tension or compression. From this viewpoint, the bendability of a sheet specimen may be evaluated, using the knowledge regarding shear band formation in Plane Strain tension/compression. To confirm this and to encompass overall deformation of a bent sheet specimen, including shear bands, finite element analyses of Plane Strain pure bending are carried out, and the predicted shear band formation in bent specimens is compared to that in the tension/compression problem. Finally, the present results are compared to previous related studies, and the efficiency of the present method for materials design in future is discussed.
