Quasi-incompressible and quasi-inextensible element and material formulation for an isotropic medium

Download
2018
Rodoplu, Burak
The contribution presents a novel finite element formulation for quasi-inextensible and quasi-incompressible finite hyperelastic behavior of transversely anisotropic materialsandaddressesitscomputationalaspects. Theformulationispresentedinpurely Eulerian setting and based on the additive decomposition of the free energy function into isotropic and anisotropic parts where the isotropic part is further decomposed intoisochoricandvolumetricparts. Forthequasi-incompressibleresponse,theQ1P0 element formulation is outlined briefly where the pressure type Lagrange multiplier anditsconjugateenterthevariationalformulationasanextendedsetofvariables. Using the similar argumentation, an extended Hu-Washizu type potential is introduced where the average volume fiber stretch and fiber stress are additional field variables. Within this context, the resulting Euler-Lagrange equations and the element formulation resulting from the extended variational principle are derived. The numerical implementation exploits the underlying variational structure leading to a canonical symmetric structure. The efficiency of the proposed approached is demonstrated through representative boundary value problems. The superiority of the proposed element formulation over the standard Q1- and Q1P0-element formulation is studied through convergence analyses. The proposed finite element formulation is modular and shows excellent performance for fiber reinforced materials in the inextensibility limit. Moreover, performance of the proposed formulation is studied for representative boundary value problems applied to soft biological tissues such as human arterial wall.

Suggestions

Questioning Degree of Accuracy Offered by the Spectral Element Method in Computational Electromagnetics
Mahariq, I.; KURT, HAMZA; Kuzuoğlu, Mustafa (2015-07-01)
In this paper, a comparison amongst the spectral element method (SEM), the finite difference method (FDM), and the first-order finite element method (FEM) is presented. For the sake of consistency, the comparison is carried out on one-dimensional and two-dimensional boundary value problems based on the same measure of error in order to emphasize on the high accuracy gained by the SEM. Then, the deterioration in the accuracy of the SEM due to the elemental deformation is demonstrated. Following this, we try ...
Least-squares finite element solution of Euler equations with H-type mesh refinement and coarsening on triangular elements
AKARGUN, Hayri Yigit; Sert, Cüneyt (2014-01-01)
Purpose - The purpose of this paper is to demonstrate successful use of least-squares finite element method (LSFEM) with h-type mesh refinement and coarsening for the solution of two-dimensional, inviscid, compressible flows.
MUTUAL COUPLING EFFECTS OF FINITE RECTANGULAR PHASED-ARRAYS
YAVUZ, H; BUYUKDURA, OM (1994-04-14)
A rigorous integral equation formulation for the analysis of a phased array of flangemounted waveguide apertures is given for a finite number of elements and nonuniform spacings. The resulting set of ihtegrd equations is reduced to a matrix equation called the coupling matrix which relates the coefficients of all the modes in all the waveguides to one another. The solution then yields the dominant mode reflection coefficient, coefficients of scattered modes and hence the field in each waveguide. The blockTo...
Non-linear progressive failure analysis of open-hole composite laminates under combined loading
Gunel, Murat; Kayran, Altan (SAGE Publications, 2013-05-01)
This article presents a finite element-based study of geometrically non-linear progressive failure analysis of open-hole composite laminates, subjected to combined in-plane and out-of-plane loading. Different ply- and constituent-based failure criteria and material property degradation schemes have been coded in Patran command language and a progressive failure analysis code is developed. Progressive failure analyses of the sample composite laminate, with an open-hole, subject to different combined loading ...
Formulation of a beam finite element for micro beams
Pehlivanoğlu, Yücel; Kadıoğlu, Fevzi Suat; Department of Mechanical Engineering (2018)
This study presents an Euler Bernoulli type micro-beam finite element for analyzing the size-dependent static and dynamic behavior of micro beams. The new element is based on Modified Couple Stress Theory (MCST). The governing equations of motion and the boundary conditions for the beam are derived and the conventional Galerkin technique is employed to formulate the finite element. The new element can be reduced to Classical Euler-Bernoulli beam element if the size-effect parameter in the element matrices i...
Citation Formats
B. Rodoplu, “Quasi-incompressible and quasi-inextensible element and material formulation for an isotropic medium,” M.S. - Master of Science, Middle East Technical University, 2018.