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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Thu, 30 May 2024 13:41:25 GMT2024-05-30T13:41:25ZA new locking-free formulation for the SHB8PS solid–shell element: non-linear benchmark problems
http://hdl.handle.net/10985/10454
A new locking-free formulation for the SHB8PS solid–shell element: non-linear benchmark problems
COMBESCURE, Alain; ABED-MERAIM, Farid
In this work, a new physically stabilized and locking-free formulation of the SHB8PS element is presented. This is a solid-shell element based on a purely 3D formulation. It has eight nodes as well as five integration points, all distributed along the “thickness” direction. Consequently, it can be used for the modeling of thin structures, while providing an accurate description of the various through-thickness phenomena. The reduced integration has been used in order to prevent some locking phenomena and to increase computational efficiency. The spurious zero-energy deformation modes due to the reduced integration are efficiently stabilized, whereas the strain components corresponding to locking modes are eliminated with a projection technique following the Enhanced Assumed Strain (EAS) method.
Mon, 01 Jan 2007 00:00:00 GMThttp://hdl.handle.net/10985/104542007-01-01T00:00:00ZCOMBESCURE, AlainABED-MERAIM, Farid In this work, a new physically stabilized and locking-free formulation of the SHB8PS element is presented. This is a solid-shell element based on a purely 3D formulation. It has eight nodes as well as five integration points, all distributed along the “thickness” direction. Consequently, it can be used for the modeling of thin structures, while providing an accurate description of the various through-thickness phenomena. The reduced integration has been used in order to prevent some locking phenomena and to increase computational efficiency. The spurious zero-energy deformation modes due to the reduced integration are efficiently stabilized, whereas the strain components corresponding to locking modes are eliminated with a projection technique following the Enhanced Assumed Strain (EAS) method.New quadratic solid-shell elements and their evaluation on popular benchmark problems
http://hdl.handle.net/10985/10458
New quadratic solid-shell elements and their evaluation on popular benchmark problems
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
In recent years, considerable effort has been devoted to the development of 3D finite elements able to model thin structures (Cho et al., 1998; Sze and Yao, 2000; Abed-Meraim and Combescure, 2002; Vu-Quoc and Tan, 2003; Chen and Wu, 2004). To this end, coupling solid and shell formulations proved to be an interesting strategy, providing continuum finite element models that can be efficiently used for structural applications. In the present work, two solid-shell elements are formulated (a 20-node and a 15-node element) based on a purely three-dimensional approach. The advantages of these elements are shown through the analysis of various structural problems. Note that their main advantage is to allow complex structural shapes to be simulated without classical problems of connecting zones meshed with different element types. These solid-shell elements have a special direction called the “thickness”, along which a set of integration points are located. Reduced integration is also used to prevent some locking phenomena and to increase computational efficiency. Focus will be placed here on linear benchmark problems, where it is shown that these solid-shell elements perform much better than their counterparts, conventional solid elements.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/104582012-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid In recent years, considerable effort has been devoted to the development of 3D finite elements able to model thin structures (Cho et al., 1998; Sze and Yao, 2000; Abed-Meraim and Combescure, 2002; Vu-Quoc and Tan, 2003; Chen and Wu, 2004). To this end, coupling solid and shell formulations proved to be an interesting strategy, providing continuum finite element models that can be efficiently used for structural applications. In the present work, two solid-shell elements are formulated (a 20-node and a 15-node element) based on a purely three-dimensional approach. The advantages of these elements are shown through the analysis of various structural problems. Note that their main advantage is to allow complex structural shapes to be simulated without classical problems of connecting zones meshed with different element types. These solid-shell elements have a special direction called the “thickness”, along which a set of integration points are located. Reduced integration is also used to prevent some locking phenomena and to increase computational efficiency. Focus will be placed here on linear benchmark problems, where it is shown that these solid-shell elements perform much better than their counterparts, conventional solid elements.An improved assumed strain solid-shell element formulation with physical stabilization for geometric non-linear applications and elastic-plastic stability analysis
http://hdl.handle.net/10985/10204
An improved assumed strain solid-shell element formulation with physical stabilization for geometric non-linear applications and elastic-plastic stability analysis
COMBESCURE, Alain; ABED-MERAIM, Farid
In this paper, the earlier formulation of the SHB8PS finite element is revised in order to eliminate some persistent membrane and shear locking phenomena. This new formulation consists of a solid-shell element based on a purely three-dimensional approach. More specifically, the element has eight nodes, with displacements as the only degrees of freedom, as well as an arbitrary number of integration points, with a minimum number of two, distributed along the 'thickness' direction. The resulting derivation, which is computationally efficient, can then be used for the modeling of thin structures, while providing an accurate description of the various through-thickness phenomena. A reduced integration scheme is used to prevent some locking phenomena and to achieve an attractive, low-cost formulation. The spurious zero-energy modes due to this in-plane one-point quadrature are efficiently controlled using a physical stabilization procedure, whereas the strain components corresponding to locking modes are eliminated with a projection technique following the assumed strain method. In addition to the extended and detailed formulation presented in this paper, particular attention has been focused on providing full justification regarding the identification of hourglass modes in relation to rank deficiencies. Moreover, an attempt has been made to provide a sound foundation to the derivation of the co-rotational coordinate frame, on which the calculations of the stabilization stiffness matrix and internal load vector are based. Finally to assess the effectiveness and performance of this new formulation, a set of popular benchmark problems is investigated, involving geometric non-linear analyses as well as elastic-plastic stability issues.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/102042009-01-01T00:00:00ZCOMBESCURE, AlainABED-MERAIM, Farid In this paper, the earlier formulation of the SHB8PS finite element is revised in order to eliminate some persistent membrane and shear locking phenomena. This new formulation consists of a solid-shell element based on a purely three-dimensional approach. More specifically, the element has eight nodes, with displacements as the only degrees of freedom, as well as an arbitrary number of integration points, with a minimum number of two, distributed along the 'thickness' direction. The resulting derivation, which is computationally efficient, can then be used for the modeling of thin structures, while providing an accurate description of the various through-thickness phenomena. A reduced integration scheme is used to prevent some locking phenomena and to achieve an attractive, low-cost formulation. The spurious zero-energy modes due to this in-plane one-point quadrature are efficiently controlled using a physical stabilization procedure, whereas the strain components corresponding to locking modes are eliminated with a projection technique following the assumed strain method. In addition to the extended and detailed formulation presented in this paper, particular attention has been focused on providing full justification regarding the identification of hourglass modes in relation to rank deficiencies. Moreover, an attempt has been made to provide a sound foundation to the derivation of the co-rotational coordinate frame, on which the calculations of the stabilization stiffness matrix and internal load vector are based. Finally to assess the effectiveness and performance of this new formulation, a set of popular benchmark problems is investigated, involving geometric non-linear analyses as well as elastic-plastic stability issues.Assumed-strain solid-shell formulation for the six-node finite element SHB6: Evaluation on non-linear benchmark problems
http://hdl.handle.net/10985/10192
Assumed-strain solid-shell formulation for the six-node finite element SHB6: Evaluation on non-linear benchmark problems
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
The current contribution proposes a six-node prismatic solid-shell denoted as (SHB6). The formulation is extended to geometric and material non-linearities, and focus will be placed on its validation on non-linear benchmark problems. The resulting derivation only involves displacement DOF, as it is based on a fully 3D approach. The motivation behind this is to allow a natural mesh connexion in problems where both structural and continuum elements need to be used. Another major interest is to complement meshes that use hexahedral finite element, especially when free mesh generation tools are employed. The assumed-strain method is combined with an in-plane one-point quadrature scheme in order to reduce both locking phenomena and computational cost. A careful analysis of possible stiffness matrix rank deficiencies shows that this reduced integration does not induce hourglass modes.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/101922012-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid The current contribution proposes a six-node prismatic solid-shell denoted as (SHB6). The formulation is extended to geometric and material non-linearities, and focus will be placed on its validation on non-linear benchmark problems. The resulting derivation only involves displacement DOF, as it is based on a fully 3D approach. The motivation behind this is to allow a natural mesh connexion in problems where both structural and continuum elements need to be used. Another major interest is to complement meshes that use hexahedral finite element, especially when free mesh generation tools are employed. The assumed-strain method is combined with an in-plane one-point quadrature scheme in order to reduce both locking phenomena and computational cost. A careful analysis of possible stiffness matrix rank deficiencies shows that this reduced integration does not induce hourglass modes.Éléments finis de type coques volumiques pour la simulation des structures minces
http://hdl.handle.net/10985/10357
Éléments finis de type coques volumiques pour la simulation des structures minces
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
Ce travail concerne le développement d’une nouvelle famille d’éléments finis (EF) de type coques volumiques quadratiques. Deux éléments seront présentés, un hexaèdre à vingt nœuds et un prisme à quinze nœuds, qui sont formulés à partir d’une approche purement tridimensionnelle. La performance de ces éléments sera montrée à travers l’analyse de problèmes structuraux variés.; This work is concerned with the development of a new family of solid–shell finite elements. Two elements will be presented, a twenty-node hexahedron and a fifteen-node prism, which are formulated based on a purely three-dimensional approach. The performance of these solid–shell elements will be shown through the analysis of various structural problems.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/103572013-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid Ce travail concerne le développement d’une nouvelle famille d’éléments finis (EF) de type coques volumiques quadratiques. Deux éléments seront présentés, un hexaèdre à vingt nœuds et un prisme à quinze nœuds, qui sont formulés à partir d’une approche purement tridimensionnelle. La performance de ces éléments sera montrée à travers l’analyse de problèmes structuraux variés.
This work is concerned with the development of a new family of solid–shell finite elements. Two elements will be presented, a twenty-node hexahedron and a fifteen-node prism, which are formulated based on a purely three-dimensional approach. The performance of these solid–shell elements will be shown through the analysis of various structural problems.A new prismatic solid-shell element 'SHB6' : assumed-strain formulation and evaluation on benchmark problems
http://hdl.handle.net/10985/10256
A new prismatic solid-shell element 'SHB6' : assumed-strain formulation and evaluation on benchmark problems
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
In this paper, the formulation of a new six-node solid–shell element denoted (SHB6) is proposed. This prismatic element is based on a purely three-dimensional approach, and hence has displacements as the only degrees of freedom. A reduced integration scheme is adopted consisting of one-point in-plane quadrature and an arbitrary number of integration points, with a minimum number of two, distributed along the ‘thickness’ direction. Moreover, in order to enhance its performance and to greatly reduce most locking effects, specific projections are introduced based on the assumed-strain method. The resulting derivation can then be used to model thin structural problems, while taking into account the various through-thickness phenomena. A careful analysis of potential stiffness matrix rank deficiencies reveals that no hourglass modes need to be controlled. However, without assumed-strain method, the element exhibits some shear and thickness-type locking, which is common in linear triangular elements associated with constant strain states. After the formulation of the element is detailed, its performance is assessed through a set of representative benchmark problems illustrating its capabilities in various situations. More specifically, this prismatic solid–shell element proves to be an essential complement to the SHB8PS hexahedral element in meshing arbitrarily complex geometries.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/102562009-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid In this paper, the formulation of a new six-node solid–shell element denoted (SHB6) is proposed. This prismatic element is based on a purely three-dimensional approach, and hence has displacements as the only degrees of freedom. A reduced integration scheme is adopted consisting of one-point in-plane quadrature and an arbitrary number of integration points, with a minimum number of two, distributed along the ‘thickness’ direction. Moreover, in order to enhance its performance and to greatly reduce most locking effects, specific projections are introduced based on the assumed-strain method. The resulting derivation can then be used to model thin structural problems, while taking into account the various through-thickness phenomena. A careful analysis of potential stiffness matrix rank deficiencies reveals that no hourglass modes need to be controlled. However, without assumed-strain method, the element exhibits some shear and thickness-type locking, which is common in linear triangular elements associated with constant strain states. After the formulation of the element is detailed, its performance is assessed through a set of representative benchmark problems illustrating its capabilities in various situations. More specifically, this prismatic solid–shell element proves to be an essential complement to the SHB8PS hexahedral element in meshing arbitrarily complex geometries.Assumed-strain solid–shell formulation for the six-node finite element SHB6: evaluation on nonlinear benchmark problems
http://hdl.handle.net/10985/10358
Assumed-strain solid–shell formulation for the six-node finite element SHB6: evaluation on nonlinear benchmark problems
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
Because accuracy and efficiency are the main features expected within the finite element (FE) method, the current contribution proposes a six-node prismatic solid–shell, denoted (SHB6). The formulation is extended here to geometric and material nonlinearities, and focus will be placed on its validation on nonlinear benchmark problems. This type of FE is specifically designed for the modeling of thin structures, by combining several useful shell features with some well-known solid element advantages. Therefore, the resulting derivation only involves displacement degrees of freedom as it is based on a fully 3D approach. Some of the motivation behind this formulation is to allow a natural mesh connection in problems where both structural (shell/plate) and continuum (solid) elements need to be simultaneously used. Another major interest of this prismatic solid–shell is to complement meshes that use hexahedral solid–shell FE, especially when free mesh generation tools are employed. To achieve an efficient formulation, the assumed-strain method is combined with an in-plane one-point quadrature scheme. These techniques are intended to reduce both locking phenomena and computational cost. A careful analysis of possible stiffness matrix rank deficiencies demonstrates that this reduced integration procedure does not induce hourglass modes and thus no stabilization is required.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/103582011-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid Because accuracy and efficiency are the main features expected within the finite element (FE) method, the current contribution proposes a six-node prismatic solid–shell, denoted (SHB6). The formulation is extended here to geometric and material nonlinearities, and focus will be placed on its validation on nonlinear benchmark problems. This type of FE is specifically designed for the modeling of thin structures, by combining several useful shell features with some well-known solid element advantages. Therefore, the resulting derivation only involves displacement degrees of freedom as it is based on a fully 3D approach. Some of the motivation behind this formulation is to allow a natural mesh connection in problems where both structural (shell/plate) and continuum (solid) elements need to be simultaneously used. Another major interest of this prismatic solid–shell is to complement meshes that use hexahedral solid–shell FE, especially when free mesh generation tools are employed. To achieve an efficient formulation, the assumed-strain method is combined with an in-plane one-point quadrature scheme. These techniques are intended to reduce both locking phenomena and computational cost. A careful analysis of possible stiffness matrix rank deficiencies demonstrates that this reduced integration procedure does not induce hourglass modes and thus no stabilization is required.Développement d’un nouvel élément fini prismatique « SHB6 » de type solide–coque : formulation et évaluation à travers des cas tests
http://hdl.handle.net/10985/10441
Développement d’un nouvel élément fini prismatique « SHB6 » de type solide–coque : formulation et évaluation à travers des cas tests
TRINH, Vuong-Dieu; COMBESCURE, Alain; ABED-MERAIM, Farid
Cet article décrit le développement d’un nouvel élément fini prismatique SHB6 de type solide-coque, obtenu à partir d’une formulation purement tridimensionnelle. Cet élément possède six nœuds et cinq points d’intégration répartis selon la direction de l’épaisseur. L’objectif étant d’avoir des éléments à géométrie volumique capables de modéliser des structures minces, tout en prenant correctement en compte les différents phénomènes à travers l’épaisseur. Afin d’améliorer ses performances de calcul et d’éviter certains blocages, l’intégration réduite a été employée. On montre d’abord que cette sous-intégration ne génère pas de modes de hourglass. Ensuite, on met en évidence que l’élément SHB6, sans aucune modification ou projection de son opérateur gradient discrétisé, peut souffrir de certains verrouillages de type cisaillement transverse ou membrane.; This paper presents the development of a new solid-shell finite element “SHB6” derived from a purely three-dimensional formulation. It has six nodes as well as five integration points, all distributed along the “thickness” direction. The main goal of this research is to develop low-order solid elements that are able to model thin structures while correctly taking into account the various through-thickness phenomena. In order to improve its calculation performances and to prevent some locking phenomena, reduced integration was used. We demonstrate first that there are no hourglass modes generated by the reduced integration. On the other hand, we show that, without any modification or projection of its discrete gradient operator, the SHB6 element could suffer from some membrane and shear locking phenomena.
Mon, 01 Jan 2007 00:00:00 GMThttp://hdl.handle.net/10985/104412007-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainABED-MERAIM, Farid Cet article décrit le développement d’un nouvel élément fini prismatique SHB6 de type solide-coque, obtenu à partir d’une formulation purement tridimensionnelle. Cet élément possède six nœuds et cinq points d’intégration répartis selon la direction de l’épaisseur. L’objectif étant d’avoir des éléments à géométrie volumique capables de modéliser des structures minces, tout en prenant correctement en compte les différents phénomènes à travers l’épaisseur. Afin d’améliorer ses performances de calcul et d’éviter certains blocages, l’intégration réduite a été employée. On montre d’abord que cette sous-intégration ne génère pas de modes de hourglass. Ensuite, on met en évidence que l’élément SHB6, sans aucune modification ou projection de son opérateur gradient discrétisé, peut souffrir de certains verrouillages de type cisaillement transverse ou membrane.
This paper presents the development of a new solid-shell finite element “SHB6” derived from a purely three-dimensional formulation. It has six nodes as well as five integration points, all distributed along the “thickness” direction. The main goal of this research is to develop low-order solid elements that are able to model thin structures while correctly taking into account the various through-thickness phenomena. In order to improve its calculation performances and to prevent some locking phenomena, reduced integration was used. We demonstrate first that there are no hourglass modes generated by the reduced integration. On the other hand, we show that, without any modification or projection of its discrete gradient operator, the SHB6 element could suffer from some membrane and shear locking phenomena.Les simulations numériques de la mise en forme sont-elles fiables ?
http://hdl.handle.net/10985/10475
Les simulations numériques de la mise en forme sont-elles fiables ?
COMBESCURE, Alain; BRUNET, Michel; MAUREL, Bertrand; NEFUSSI, Germaine; ABED-MERAIM, Farid
Cette présentation porte un regard critique quant aux capacités des simulations actuelles (utilisant les logiciels de calcul par éléments finis disponibles) à prédire de manière fiable les phénomènes observés lors de la mise en forme des matériaux métalliques et dans les procédés de fabrication associés.
Tue, 01 Jan 2008 00:00:00 GMThttp://hdl.handle.net/10985/104752008-01-01T00:00:00ZCOMBESCURE, AlainBRUNET, MichelMAUREL, BertrandNEFUSSI, GermaineABED-MERAIM, Farid Cette présentation porte un regard critique quant aux capacités des simulations actuelles (utilisant les logiciels de calcul par éléments finis disponibles) à prédire de manière fiable les phénomènes observés lors de la mise en forme des matériaux métalliques et dans les procédés de fabrication associés.New prismatic solid-shell element: Assumed strain formulation and evaluation on benchmark problems
http://hdl.handle.net/10985/10374
New prismatic solid-shell element: Assumed strain formulation and evaluation on benchmark problems
TRINH, Vuong-Dieu; COMBESCURE, Alain; TRINH, Vuong-Dieu; ABED-MERAIM, Farid
This paper presents the development of a six-node solid-shell finite element called (SHB6) and based on the assumed strain method adopted by Belytschko et al. [2]. It is integrated with a set of five Gauss points along a special direction, denoted “thickness”, and with only one point in the other in-plane directions. Its discrete gradient is modified in order to attenuate shear and membrane locking. A series of popular linear benchmark problems has been carried out with comparisons to geometrically similar, low-order three-dimensional elements.
Tue, 01 Jan 2008 00:00:00 GMThttp://hdl.handle.net/10985/103742008-01-01T00:00:00ZTRINH, Vuong-DieuCOMBESCURE, AlainTRINH, Vuong-DieuABED-MERAIM, Farid This paper presents the development of a six-node solid-shell finite element called (SHB6) and based on the assumed strain method adopted by Belytschko et al. [2]. It is integrated with a set of five Gauss points along a special direction, denoted “thickness”, and with only one point in the other in-plane directions. Its discrete gradient is modified in order to attenuate shear and membrane locking. A series of popular linear benchmark problems has been carried out with comparisons to geometrically similar, low-order three-dimensional elements.