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Logo: Institut für Kontinuumsmechanik/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institut für Kontinuumsmechanik/Leibniz Universität Hannover
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Finite-Elemente Technologie

A 3D CAD/CAE integration using isogeometric symmetric Galerkin boundary element method

 
 

 

A 3D CAD/CAE integration using isogeometric symmetric Galerkin boundary element method

Bild zum Projekt A 3D CAD/CAE integration using isogeometric symmetric Galerkin boundary element method

Leitung:

X. Zhuang

Bearbeitung:

Binh H. Nguyen

Kurzbeschreibung:

A seamless communication of computer aided design (CAD) and computer aided engineering (CAE) has always been the ultimate goal in product lifecycle management. The forward in- tegration CAD/CAE, in which the simulation tasks are operated directly on CAD model, can be achieved by the isogeometric analysis (IGA) within the conventional finite element method (FEM). Despite of this successful implementation that covers many engineering aspects, the crucial challenge in this CAD/CAE integration is the incompatible geometric representation, namely the volumetric representation of CAE versus the boundary representation of CAD in three-dimensional problems.

 

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Large Deformation Cohesive-Zone Element for Fracture in Rubbery Polymers

Bild zum Projekt Large Deformation Cohesive-Zone Element for Fracture in Rubbery Polymers

Leitung:

P. Wriggers

Bearbeitung:

A. B. Harish

Kurzbeschreibung:

In this work, a 3D cohesive zone element is developed considering material and geometric nonlinearities and suitable for modeling large deformations and rotations.

 

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Modeling 3D crack coalescence and percolation with the XFEM and level sets

 

Leitung:

S. Löhnert, E. Budyn

Bearbeitung:

H. Attar

Kurzbeschreibung:

In three dimensions the accurate geometrical and mechanical modeling of crack coalescence, crack percolation and the splitting of cracks due to dynamic processes is a severe challenge. Using the XFEM in combination with level sets, new enrichment patterns as well as multiple level set functions need to be defined to account for the complex crack geometries and discontinuities within elements. In addition the definition of accurate fracture criteria for more complex material models remains a challenge. In this project crack coalescence and percolation in three dimensions is investigated in detail and accurate fracture criteria for elastoplastic material behavior within the fracture process zone are developed.

 

 

Application of the Virtual Element Method to Non-Conforming Contact Interfaces

Bild zum Projekt Application of the Virtual Element Method to Non-Conforming Contact Interfaces

Leitung:

P. Wriggers

Bearbeitung:

W.T. Rust

Kurzbeschreibung:

When using standard Finite Elements the discretization is subject to limitations depending on the element geometry. In contrast to this the Virtual Element Method offers the possibility for elements with an arbitrary number of nodes and special geometries like non-convex polygons or hanging nodes. In this Project the application of the Virtual Elements to different problems is investigated. Here it is used to create an efficient contact discretization.

 

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Numerical simulations of delamination in FRP shell structures using XFEM

Bild zum Projekt Numerical simulations of delamination in FRP shell structures using XFEM

Leitung:

Prof. Wilhelm J.H. Rust, Prof. P. Wriggers

Bearbeitung:

Saleh Yazdani

Kurzbeschreibung:

When using Fiber Reinforced Plastics (FRP) delamination can occur leading to significant reduction of the load carrying capacity of a structure. Here the focus is on structural stability (buckling and snap-through). Furthermore, the propagation of delamination in pre- and postbuckling regime is of interest. A standard model for such simulations consists either of two shell elements with nodes at a given location of delamination or of a stack of shell-like solids, one per layer. The former has limits in its application while the latter leads to enormous computational effort. In this project eXtended FEM is applied to structural delamination problems. This allows the description of delamination at arbitrary through-the-thickness locations by means of shape functions enriched for discontinuities. Criteria for starting and propagating delamination should be integrated, if applicable combined with cohesive zone models. Contact in a delaminated zone must be accounted for. The new element must be suitable for large rotations and buckling.

 

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