Analytical Solutions for Inextensible Fiber-Reinforced Dielectric Elastomer Torsional Actuators

Two types of tubular dielectric elastomers (DE) torsional actuators are studied in this work, which are, respectively, reinforced by a family and two families of helical inextensible fibers. When subject to a radial electric field, torsional deformation will be induced in the DE actuators due to the constraint of inextensible fibers. By conducting finite deformation analysis with the principal axis approach and adopting appropriate constitutive equations, simple analytical solutions are obtained for the considered DE actuators. Furthermore, the effects of material parameters and the fiber angles as well as externally applied axial force and twist moment on the voltage-induced torsional behaviors of the two DE actuators are discussed in order to explore their maximum torsional actuation capability. The concept design presented here provides an effective approach for achieving large torsional deformation, and the developed model and revealed results will aid the design and fabrication of soft actuators and soft robots.

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Soil-Water Coupled Finite Deformation Analysis of Seismic Deformation and Failure of Embankment on Horizontal and Inclined Ground

Soil Dynamics and Earthquake Engineering ◽

10.1061/41102(375)16 ◽

2010 ◽

Author(s):

Masaki Nakano ◽

Takayuki Sakai ◽

Toshihiro Noda ◽

Akira Asaoka

Keyword(s):

Soil Water ◽

Finite Deformation ◽

Deformation Analysis ◽

Deformation And Failure ◽

Seismic Deformation

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A Two-Dimensional Linear Assumed Strain Triangular Element for Finite Deformation Analysis

Journal of Applied Mechanics ◽

10.1115/1.2173674 ◽

2005 ◽

Vol 73 (6) ◽

pp. 970-976 ◽

Cited By ~ 4

Author(s):

Fernando G. Flores

Keyword(s):

Finite Deformation ◽

Degrees Of Freedom ◽

Yield Function ◽

Triangular Element ◽

Deformation Analysis ◽

Elastic Model ◽

Stress Strain ◽

Metric Tensor ◽

Assumed Strain ◽

Non Linear

An assumed strain approach for a linear triangular element able to handle finite deformation problems is presented in this paper. The element is based on a total Lagrangian formulation and its geometry is defined by three nodes with only translational degrees of freedom. The strains are computed from the metric tensor, which is interpolated linearly from the values obtained at the mid-side points of the element. The evaluation of the gradient at each side of the triangle is made resorting to the geometry of the adjacent elements, leading to a four element patch. The approach is then nonconforming, nevertheless the element passes the patch test. To deal with plasticity at finite deformations a logarithmic stress-strain pair is used where an additive decomposition of elastic and plastic strains is adopted. A hyper-elastic model for the elastic linear stress-strain relation and an isotropic quadratic yield function (Mises) for the plastic part are considered. The element has been implemented in two finite element codes: an implicit static/dynamic program for moderately non-linear problems and an explicit dynamic code for problems with strong nonlinearities. Several examples are shown to assess the behavior of the present element in linear plane stress states and non-linear plane strain states as well as in axi-symmetric problems.

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