Session Details
MS15-2: Non-standard Formulations and Discretization Methods for Thin-walled Structures (Ganzes Minisymposium anzeigen)
Wednesday, 11. October 2017; 16:00 - 18:00 Uhr in Raum 7.01
Sitzungsleitung: Wolfgang Dornisch
16:00
A Discretization Independent Methodology for Mixed Methods
Simon Bieber (University of Stuttgart), Bastian Oesterle (University of Stuttgart), Ekkehard Ramm (University of Stuttgart), Manfred Bischoff (University of Stuttgart)
Kurzfassung:
Nowadays a broad range of different discretization methods, such as (isogeometric) spline based finite element approaches, collocation or meshless methods are available to compute approximate solutions for boundary value problems. Locking is a common issue for primal formulations in all these schemes and formulations based on mixed methods may be favorable. A general methodology will be presented to construct necessary strain/stress ansatz spaces, independent of the discretization method.
A Discretization Independent Methodology for Mixed Methods
Simon Bieber (University of Stuttgart), Bastian Oesterle (University of Stuttgart), Ekkehard Ramm (University of Stuttgart), Manfred Bischoff (University of Stuttgart)
Kurzfassung:
Nowadays a broad range of different discretization methods, such as (isogeometric) spline based finite element approaches, collocation or meshless methods are available to compute approximate solutions for boundary value problems. Locking is a common issue for primal formulations in all these schemes and formulations based on mixed methods may be favorable. A general methodology will be presented to construct necessary strain/stress ansatz spaces, independent of the discretization method.
16:20
Hierarchic Isogeometric Large Rotation Shell Elements Including Linearized Transverse Shear Parametrization
Renate Sachse (University of Stuttgart), Bastian Oesterle (University of Stuttgart), Ekkehard Ramm (University of Stuttgart), Manfred Bischoff (University of Stuttgart)
Kurzfassung:
Two novel hierarchic isogeometric formulations for geometrically nonlinear shell analysis including transverse shear effects are presented. Both concepts combine a fully nonlinear rotation-free Kirchhoff-Love shell model with hierarchically added linearized transverse shear components. An additive split of Green-Lagrange strains dramatically facilitates representing large rotations in shell analysis while the proposed hierarchic concepts are intrinsically free from transverse shear locking.
Hierarchic Isogeometric Large Rotation Shell Elements Including Linearized Transverse Shear Parametrization
Renate Sachse (University of Stuttgart), Bastian Oesterle (University of Stuttgart), Ekkehard Ramm (University of Stuttgart), Manfred Bischoff (University of Stuttgart)
Kurzfassung:
Two novel hierarchic isogeometric formulations for geometrically nonlinear shell analysis including transverse shear effects are presented. Both concepts combine a fully nonlinear rotation-free Kirchhoff-Love shell model with hierarchically added linearized transverse shear components. An additive split of Green-Lagrange strains dramatically facilitates representing large rotations in shell analysis while the proposed hierarchic concepts are intrinsically free from transverse shear locking.
16:40
Generalized local B-bar method for locking phenomenon in Reissner-Mindlin shell and skew-symmetric Nitsche method for boundary conditions imposing and patch coupling in IGA
Qingyuan Hu (University of Luxembourg), Franz Chouly (Université Bourgogne Franche-Comté), Andreas Zilian (University of Luxembourg), Gengdong Cheng (Dalian University of Technology), Stéphane Bordas (University of Luxembourg)
Kurzfassung:
We adopt the generalized local B-bar method to deal with the locking phenomenon in Reissner-Mindlin shell. The local element-wise projection saves computational effort, and projected basis functions of different orders are used to achieve good accuracy. The skew-symmetric Nitsche method is introduced for boundary conditions imposing and patch coupling. It has an advantage of unconditional stability wrt the stable parameter, i.e. parameter-free.
Generalized local B-bar method for locking phenomenon in Reissner-Mindlin shell and skew-symmetric Nitsche method for boundary conditions imposing and patch coupling in IGA
Qingyuan Hu (University of Luxembourg), Franz Chouly (Université Bourgogne Franche-Comté), Andreas Zilian (University of Luxembourg), Gengdong Cheng (Dalian University of Technology), Stéphane Bordas (University of Luxembourg)
Kurzfassung:
We adopt the generalized local B-bar method to deal with the locking phenomenon in Reissner-Mindlin shell. The local element-wise projection saves computational effort, and projected basis functions of different orders are used to achieve good accuracy. The skew-symmetric Nitsche method is introduced for boundary conditions imposing and patch coupling. It has an advantage of unconditional stability wrt the stable parameter, i.e. parameter-free.
17:00
A method for the elimination of shear locking effects in an isogeometric Reissner-Mindlin shell formulation
Georgia Kikis (RWTH Aachen University), Wolfgang Dornisch (University of Kaiserslautern), Sven Klinkel (RWTH Aachen University)
Kurzfassung:
Shell elements for slender structures based on a Reissner-Mindlin approach struggle in pure bending problems. The stiffness of such structures is overestimated due to the transversal shear locking effect. Here, an isogeometric Reissner-Mindlin shell element is presented, which uses adjusted control meshes for the displacements and rotations in order to create a conforming interpolation of the pure bending compatibility requirement. The method is tested for standard numerical examples.
A method for the elimination of shear locking effects in an isogeometric Reissner-Mindlin shell formulation
Georgia Kikis (RWTH Aachen University), Wolfgang Dornisch (University of Kaiserslautern), Sven Klinkel (RWTH Aachen University)
Kurzfassung:
Shell elements for slender structures based on a Reissner-Mindlin approach struggle in pure bending problems. The stiffness of such structures is overestimated due to the transversal shear locking effect. Here, an isogeometric Reissner-Mindlin shell element is presented, which uses adjusted control meshes for the displacements and rotations in order to create a conforming interpolation of the pure bending compatibility requirement. The method is tested for standard numerical examples.
17:20
Analysis of axisymmetric shells based on the scaled boundary finite element method
Milan Wallner (University of Duisburg-Essen), Carolin Birk (University of Duisburg-Essen), Hauke Gravenkamp (University of Duisburg-Essen)
Kurzfassung:
In this contribution the SBFEM is used to analyse axisymmetric shell structures. A simplified plane strain arch formulation to approximate a cylindrical shell will be presented. This approximation already shows a high correlation with the membrane theory of shells. Furthermore, first results obtained for a 3D shell formulation used to analyse an axisymmetric spherical shell will illustrate the potential of the SBFEM to minimize locking effects when modelling shell structures.
Analysis of axisymmetric shells based on the scaled boundary finite element method
Milan Wallner (University of Duisburg-Essen), Carolin Birk (University of Duisburg-Essen), Hauke Gravenkamp (University of Duisburg-Essen)
Kurzfassung:
In this contribution the SBFEM is used to analyse axisymmetric shell structures. A simplified plane strain arch formulation to approximate a cylindrical shell will be presented. This approximation already shows a high correlation with the membrane theory of shells. Furthermore, first results obtained for a 3D shell formulation used to analyse an axisymmetric spherical shell will illustrate the potential of the SBFEM to minimize locking effects when modelling shell structures.