Similar to plane strain, axisymmetric stress problem is also highly kinematics constrained. Standard displacement-based finite element exhibits volumetric locking issue in simulating nearly/fully incompressible material or isochoric plasticity under axisymmetric loading conditions, which severely underestimates the deformation and overestimates the bearing capacity for structural/geotechnical engineering problems. The aim of this paper is to apply variational multiscale method to produce a stabilized mixed displacement-pressure formulation, which can effectively alleviate the volumetric locking issue for axisymmetric stress problem. Both nearly incompressible elasticity and isochoric J2 elastoplasticity are investigated. First-order 3-node triangular and 4-node quadrilateral elements are tested for locking issues. Severalrepresentative simulations are provided to demonstrate the performance of the linear elements, which include the convergence study and comparison with closed-form solutions. A comparative study with pressure Laplacian stabilized formulation is also presented. Copyright © 2009 John Wiley & Sons, Ltd.
lunes, 26 de octubre de 2009
A multiscale finite element formulation for axisymmetric elastoplasticity with volumetric locking
Similar to plane strain, axisymmetric stress problem is also highly kinematics constrained. Standard displacement-based finite element exhibits volumetric locking issue in simulating nearly/fully incompressible material or isochoric plasticity under axisymmetric loading conditions, which severely underestimates the deformation and overestimates the bearing capacity for structural/geotechnical engineering problems. The aim of this paper is to apply variational multiscale method to produce a stabilized mixed displacement-pressure formulation, which can effectively alleviate the volumetric locking issue for axisymmetric stress problem. Both nearly incompressible elasticity and isochoric J2 elastoplasticity are investigated. First-order 3-node triangular and 4-node quadrilateral elements are tested for locking issues. Severalrepresentative simulations are provided to demonstrate the performance of the linear elements, which include the convergence study and comparison with closed-form solutions. A comparative study with pressure Laplacian stabilized formulation is also presented. Copyright © 2009 John Wiley & Sons, Ltd.
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