A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage

A 3D mixed beam finite element is presented, modeling the warping of the cross-sections as an independent kinematic field. The beam formulation is derived on the basis of the Hu-Washizu variational principle, expressed as function of four independent fields: the standard displacements, strains and...

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Main Authors: D. Addessi, P. Di Re
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2014-07-01
Series:Fracture and Structural Integrity
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Online Access:http://www.gruppofrattura.it/pdf/rivista/numero29/numero_29_art_16.pdf
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author D. Addessi
P. Di Re
author_facet D. Addessi
P. Di Re
author_sort D. Addessi
collection DOAJ
description A 3D mixed beam finite element is presented, modeling the warping of the cross-sections as an independent kinematic field. The beam formulation is derived on the basis of the Hu-Washizu variational principle, expressed as function of four independent fields: the standard displacements, strains and stresses and the additional warping displacement. This is interpolated along the beam axis and on the cross-section, by placing on it a regular grid of interpolation points and adopting Lagrange polynomials. The warping degrees of freedom defined at the cross-section interpolation points are condensed, thus preserving the element matrix and vector sizes. A fiber discretization of the cross-sections is adopted. The constitutive relationship at the midpoint of each fiber is based on an isotropic damage model for brittle-like materials, distinguishing between the damage variables in tension and in compression to properly describe the unilateral effect. An efficient algorithm is formulated for the element state determination, based on a consistent linearization of the governing equations. A simple numerical application on a cantilever beam with torsion in the linear elastic range is presented and two torsion tests on plain concrete beams are performed, by comparing the numerical results with the experimental outcomes.
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institution Kabale University
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series Fracture and Structural Integrity
spelling doaj-art-32bd61e00b034e2cabd76970f1c79f6c2025-01-02T20:54:05ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89931971-89932014-07-0182917819510.3221/IGF-ESIS.29.16A 3D mixed frame element with multi-axial coupling for thin-walled structures with damageD. Addessi0P. Di Re1University of Rome ‘Sapienza’University of Rome ‘Sapienza’A 3D mixed beam finite element is presented, modeling the warping of the cross-sections as an independent kinematic field. The beam formulation is derived on the basis of the Hu-Washizu variational principle, expressed as function of four independent fields: the standard displacements, strains and stresses and the additional warping displacement. This is interpolated along the beam axis and on the cross-section, by placing on it a regular grid of interpolation points and adopting Lagrange polynomials. The warping degrees of freedom defined at the cross-section interpolation points are condensed, thus preserving the element matrix and vector sizes. A fiber discretization of the cross-sections is adopted. The constitutive relationship at the midpoint of each fiber is based on an isotropic damage model for brittle-like materials, distinguishing between the damage variables in tension and in compression to properly describe the unilateral effect. An efficient algorithm is formulated for the element state determination, based on a consistent linearization of the governing equations. A simple numerical application on a cantilever beam with torsion in the linear elastic range is presented and two torsion tests on plain concrete beams are performed, by comparing the numerical results with the experimental outcomes.http://www.gruppofrattura.it/pdf/rivista/numero29/numero_29_art_16.pdfThin-walled structures; Mixed beam formulation; Warping; Damage; Softening; Regularization.
spellingShingle D. Addessi
P. Di Re
A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
Fracture and Structural Integrity
Thin-walled structures; Mixed beam formulation; Warping; Damage; Softening; Regularization.
title A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
title_full A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
title_fullStr A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
title_full_unstemmed A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
title_short A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage
title_sort 3d mixed frame element with multi axial coupling for thin walled structures with damage
topic Thin-walled structures; Mixed beam formulation; Warping; Damage; Softening; Regularization.
url http://www.gruppofrattura.it/pdf/rivista/numero29/numero_29_art_16.pdf
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