scholarly journals A complete direct approach to nonlinear modeling of dielectric elastomer plates

2019 ◽  
Vol 230 (11) ◽  
pp. 3923-3943 ◽  
Author(s):  
Elisabeth Hansy-Staudigl ◽  
Michael Krommer ◽  
Alexander Humer
Keyword(s):  
Free Energy ◽  
Nonlinear Modeling ◽  
Three Dimensional ◽  
Direct Approach ◽  
Thin Plates ◽  
Elastic Behavior ◽  
Dielectric Elastomers ◽  
Novel Approach ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract In this paper, we present a complete direct approach to nonlinear modeling of thin plates, which are made of incompressible dielectric elastomers. In particular, the dielectric elastomers are assumed to exhibit a neo-Hookean elastic behavior, and the effect of electrostatic forces is incorporated by the purely electrical contribution to the augmented Helmholtz free energy. Our approach does not involve any extraction-type procedure from the three-dimensional energy to derive the plate augmented free energy, but directly postulates the form of this energy for the structural plate problem treated in this paper. Results computed within the framework of this novel approach are compared to results available in the literature as well as to our own three-dimensional finite element solutions. A very good agreement is found.

Numerical evaluation of a deeply buried pipe testing facility

2018 ◽  
Vol 21 (16) ◽  
pp. 2571-2588 ◽  
Author(s):  
Van Thien Mai ◽  
Neil Hoult ◽  
Ian Moore
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
Friction Angle ◽  
Buried Pipe ◽  
Overburden Pressure ◽  
Testing Procedures ◽  
Novel Approach ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact

A new facility for testing pipes under deep burial has been developed. However, before the facility was commissioned, the influence of the loading scheme and boundary conditions on the pipe behaviour was investigated so that the most appropriate experimental setup could be developed. Two- and three-dimensional finite element analyses were used to assess the impact of the top and side boundary conditions on both flexible and rigid pipes with varying diameters. The vertical overburden pressures expected in the field are simulated using actuators applying vertical forces to two steel grillages. The numerical results show that the use of two independent grillages on the surface produced a more uniformly distributed ‘overburden’ pressure, a novel approach that performs significantly better than previous loading systems. Proximity of the test facility’s walls to the pipes was also investigated and found to have less than a 0.2% impact on pipe response when compared to simulations of field geometries. Results examining five different approaches to reducing the effect of sidewall friction were compared to the case of zero friction (i.e. the field case), and it was found that while lubricating the wall to create a friction angle of 5° over the full height produced the most accurate results, lubrication of only the top 2.5 m of the wall also produces thrust forces and bending moments within 10% of values from the zero-friction case. Finally, the effect of the position of the pipe within the test cell was investigated, where pipe testing with 0.3 m of bedding is expected to produce results like those for pipes close to rock foundations in the field. These results are already being used to inform testing procedures using this unique facility.

Elastic Behavior of Cylindrical Vessels With Lateral Nozzle Under Internal Pressure

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
P. Gao ◽  
N. Li ◽  
Z. F. Sang ◽  
G. E. O. Widera
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Deformation Characteristic ◽  
Longitudinal Section ◽  
Elastic Behavior ◽  
Lateral Angle ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The objective of this work is to study the elastic stress distribution, deformation characteristic, and stress concentration factor (SCF) of a cylindrical vessel with lateral nozzle. Three full scale vessels under internal pressure with different geometric dimensions and lateral angle θ(θ=30 deg,45 deg,60 deg) are investigated by both experimental and three-dimensional finite element methods under internal pressure. A detailed stress distribution and the SCFs of the model vessels are provided. The results indicate that the maximum stress of cylindrical vessels with a lateral nozzle occurs at the acute side of the cylinder-lateral intersection and drifts off the longitudinal section of the cylinder for about 20 deg. When the geometric parameters of the vessels (d/D,D/T,t/T) are fixed, the SCF of the structure will increase with a decrease in the lateral angle θ.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Tire Modeling by Finite Elements

1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rolling Contact ◽  
Test Problems ◽  
State Behavior ◽  
Normal Contact ◽  
New Developments ◽  
Applied Torque ◽  
Dimensional Finite Element ◽  
Tire Modeling ◽  
Three Dimensional Finite Element

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.

Sign in / Sign up

Export Citation Format

Share Document