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Logo: Institute of Continuum Mechanics/Leibniz Universität Hannover
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Logo: Institute of Continuum Mechanics/Leibniz Universität Hannover
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Projects of Prof. Dr.-Ing. habil. Dr. h.c. mult. Dr.-Ing. E.h. Peter Wriggers

Contact Mechanics

Towards multiscale modeling of Abrasive wear

Bild zum Projekt Towards multiscale modeling of Abrasive wear

Supervisor:

P. Wriggers

Researcher:

A. B. Harish

Brief description:

The work is motivated towards understanding wear as a multiscale-multiphysics approach. A 3D framework is developed to simulate cracks propagation in a microstructure due to contact loading to eventually predict wear trends in filled elastomeric compounds.

 

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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

Supervisor:

P. Wriggers

Researcher:

W. Rust

Brief description:

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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Contact models for soil mechanics

Bild zum Projekt Contact models for soil mechanics

Supervisor:

P. Wriggers

Researcher:

C. Weißenfels

Brief description:

The installation of foundations influences strongly the load bearing capacity of the soil. The large discrepancy between experimental and numerical results, using Coulomb friction law for modeling the soil structure interaction, points out that new strategies to solve this kind of problems are necessary. Experimental observations show that for rough surfaces of the structure the friction angle at the contact zone corresponds to the friction angle of the soil. This leads to the conclusion that the contact zone lies completely within the soil. A way to improve the friction laws for soil structure interactions is to project the soil models onto the contact surface which is the motivation of this work.

 

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MULTISCALE CONTACT HOMOGENIZATION OF GRANULAR INTERFACES

Bild zum Projekt MULTISCALE CONTACT HOMOGENIZATION OF GRANULAR INTERFACES

Supervisor:

P. Wriggers, I. Temizer

Researcher:

R. Weidlich

Brief description:

Dry granular third bodies are frequently encountered at multiple scales of contact interfaces in contexts that range from mechanical problems of tire traction and semiconductor manufacturing to biological problems of wear debris generation and mobility in implant joints. The investigations that are envisaged within this proposal will provide further insight into the modeling and simulation of third body effects in a fully nonlinear three-dimensional virtual setting that accounts for inelastic phenomena.

 

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Mutiscale FEM approach for rubber friction on rough surfaces

Bild zum Projekt Mutiscale FEM approach for rubber friction on rough surfaces

Supervisor:

P. Wriggers

Researcher:

P. Wagner

Brief description:

Understanding the frictional behaviour of elastomers on rough surfaces is of high practical importance in many industrial applications. For example the traction of a tire is directly linked to the material properties of the considered elastomer and the surface conditions of the road track. One goal of our studies is to gain a deeper understanding of the underlying contact physics at all length scales. Another aim is to determine a macroscopic coefficient of friction for varying material and surface properties and to validate the results with experimental data.

 

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Constitutive Modelling of Materials

In silico morphogenesis of collagen tissues for targeted drugs and bio-printing

 

Supervisor:

M. Marino

Funded by:

Masterplan SmartBiotecs, MWK (Lower Saxony, Germany)

Brief description:

This project targets to understand the mechanisms behind the morphogenesis and the development of living tissues. To this aim, mechanical and biological actions that contribute to confer tissue desired topology and functionality will be modelled and analysed in silico. A computational framework for the modeling of tissue morphogenesis in natural and bio-printed systems will be developed. In particular, the project will address: the multiscale hierarchical and organized arrangement of tissue constituents; the chemo-mechanical interaction among tissue constituents and among cells; the chemo-mechano-biological mechanisms driving growth and remodeling; the extrusion and the curing of multicellular aggregates blended with bio-inks. Obtained results will target to elucidate mechanisms behind tissue functional/dysfunctional structure; conceive targeted drug systems for stimulating optimal molecular pathways promoting tissue healing; develop novel or optimize existing 3D bio-printing technologies.

 

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Hypoplastic material models for soil-structure interaction problems

Bild zum Projekt Hypoplastic material models for soil-structure interaction problems

Supervisor:

P. Wriggers, C. Weissenfels

Researcher:

A. B. Harish

Brief description:

In this work, a hypoplastic material model is implemented using AceGen with an eventual goal to model soil-structure interaction.

 

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Nanoindentation for material property characterization

Bild zum Projekt Nanoindentation for material property characterization

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

A. B. Harish, V. Kruppernikova

Brief description:

In this work, techniques are developed for nanoindentation of soft polymers and brittle powdery materials and measurement of properties like modulus, hardness and fracture toughness.

 

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Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers

Bild zum Projekt Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers

Supervisor:

P. Wriggers, J. J. Rimoli

Researcher:

A. B. Harish, A. B. Shah

Brief description:

The work was done in collaboration with Mrs. Aarohi B. Shah and Dr. Julian J Rimoli of School of Aerospace Engineering, Georgia Tech, USA. In this work, we investigate non-crystallizing nanoparticle-reinforced polymers. The effects of the interface rubber between elastomeric matrix and filler particles and its alteration are investigated as a primary cause of Mullins and Payne effect.

 

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Constitutive modeling of large deformation behavior of filled elastomers

Bild zum Projekt Mesoscale modeling of large deformation behavior of nanoparticle-reinforced elastomers

Supervisor:

P.. Wriggers

Researcher:

A. B. Harish

Brief description:

In this work, a finite thickness cohesive zone model is used to study the large deformation & fracture behavior of filled elastomeric materials at the mesoscale. The study includes and has implications on filler cluster breakage, Mullins softening etc.

 

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Modelling and simulation of the joining zone during the tailored forming process

Bild zum Projekt Modelling and simulation of the joining zone during the tailored forming process

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

M. Baldrich, F. Töller

Funded by:

DFG im Rahmen des SFB 1153

Brief description:

[Translate to Englisch:] The topic of project C4 is the multiphysical modelling and simulation of the microstructural behaviour of the joining zone during the tailored forming process. The goal is the determination of the macroscopic, effective, thermomechanical properties of joining zones during and after forming.The model will be able to capture the contact and diffusion processes during joining, the thermal and mechanical properties during forming as well as the material behaviour during heat treatment which is responsible for calibrating material properties.

 

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Computational multiscale modelling of localized ductile failure

Bild zum Projekt Mehrskalenmodellierung von lokalisiertem duktilen Versagen

Supervisor:

P. Wriggers

Researcher:

H. Clasen

Funded by:

DFG im Normalverfahren

Brief description:

Many phenomenological material models capture ductile damage. However, to flexibly incorporate the underlying the governing microstructural properties and damage mechanisms, a multiscale framework is needed. The few recent numerical multiscale works on localized failure are limited to brittle microdamage. Therefore, the goal of this project is to provide a computational multiscale framework for the modelling of localized failure stemming from a microstructure undergoing ductile damage.

 

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Multiscale Methods for Fracturing Solids

Bild zum Projekt Multiscale Methods for Fracturing Solids

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

D. Müller-Hoeppe

Brief description:

In this project multiscale methods and homogenization techniques for the numerical simulation of three dimensional fracture processes are developed. These methods are important in aerospace and automotive industries and many other fields of mechanical and civil engineering as well as in bio-mechanics and material science. They will improve the prediction of the failure of structures.

 

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Crack propagation and crack coalescence in a multiscale framework

Bild zum Projekt Crack propagation and crack coalescence in a multiscale framework

Supervisor:

S. Löhnert, P. Wriggers

Researcher:

M. Holl

Brief description:

In this project a numerical framework for propagating and intersecting cracks on micro and macro scales is set up. Modeling cracks using the eXtended Finite Element Method (XFEM) provides an accurate and efficient numerical framework to model propagating and intersecting cracks. Since cracks of different length scales are assumed, a multiscale method is applied in order to be numerical efficient.

 

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Multiscale modeling and extended finite element analysis of fracture processes in ceramics

Bild zum Projekt Multiskalenmodellierung und erweiterte finite Elmente Analyse von Bruchprozessen in Keramik

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

C. Prange

Brief description:

The extended finite element method (XFEM) enables the modelling and calculation of cracks independent of mesh topologies. Due to this advantage it has become the most widely used method for computations of fracture processes. In the vicinity of a macrocrack front the microstructure of the material can have a significant influence and needs to be considered in detail. Especially microcracks can affect crack propagation drastically. This leads to the necessity of multiscale methods like the multiscale projection method to capture microstructural details where necessary. Even though the XFEM is known to be a comparably accurate method to calculate cracks, discretisation errors occur. Therefore, the discretisation error on the finescale is estimated via a stress smoothing technique. The realtive error of stresses enables adaptive mesh refinement on the microscale leading to more accurate results also on the macroscale. The computational model is validated by comparison of the results to experimental data.

 

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ADAPTIVE MULTISCALE MODELING AND ANALYSIS OF HETEROGENEOUS MATERIALS

Bild zum Projekt ADAPTIVE MULTISCALE MODELING AND ANALYSIS OF HETEROGENEOUS MATERIALS

Supervisor:

P. Wriggers, I. Temizer

Brief description:

Accurate computational analyses of a composite structure requires multiple levels of resolution: (i) a region where effective elastic properties are employed, (ii) a region where embedded micro-macro problems are solved, and (iii) a region where explicit microstructural evaluation is required. Development of such computational schemes for the adaptive multiscale analysis of heterogeneous materials is the main purpose of this project.

 

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FAILURE ANALYSIS - ERROR ESTIMATION FOR MULTISCALE METHODS

Bild zum Projekt FAILURE ANALYSIS - ERROR ESTIMATION FOR MULTISCALE METHODS

Supervisor:

P. Wriggers

Researcher:

N. Hajibeik

Brief description:

This project is concerned with the development of tools for error-estimation based adaptive multiscale failure analysis. In order to enable a more accurate mechanical analysis of composite aircraft substructures, existing discretisation error estimators will be improved to be used as indicators for mesh refinement. Additionally, physical error estimators will be developed to identify regions where higher-order material modelling is required.

 

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DEVELOPMENT OF A MATERIAL MODEL FOR METAL SHEETS AT FINITE DEFORMATION

Bild zum Projekt DEVELOPMENT OF A MATERIAL MODEL FOR METAL SHEETS AT FINITE DEFORMATION

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

E. Lehmann, S. Zeller

Brief description:

[Translate to Englisch:] Technical procedures claim an improved material model for the simulation of metal forming processes. An effective, anisotropic elastoplastic material model for the macroscopic material behaviour for sheet metals is developed for further usage in commercial finite element programs.

 

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Discrete Elements and Molecular Dynamics

Discrete Element Method

Bild zum Projekt Discrete Element Method

Supervisor:

P. Wriggers

Researcher:

B. Avci

Brief description:

This project is concerned with the development of a discrete element method (DEM) code for the simulation of large particle systems in 3-D, where also complex moving boundary geometries can be taken into account. The DEM is a well established numerical method to simulate systems consisting of granular matter. Granular mixing, tumbling mills, transport of particles via conveyor belts or screw conveyors are just some examples of important particulate processes in industry sectors like mining, pharmaceutical and food industries. For such systems, the optimization of the design variables as well as the appropriate choice of the operating parameters is still a difficult and a challenging task.

 

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Finite-Element Technologie

Large Deformation Cohesive-Zone Element for Fracture in Rubbery Polymers

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

Supervisor:

P. Wriggers

Researcher:

A. B. Harish

Brief description:

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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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

Supervisor:

P. Wriggers

Researcher:

W. Rust

Brief description:

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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SPP 1748 - Foundation and application of generalized mixed FEM towards nonlinear problems in solid mechanics

Bild zum Projekt SPP 1748 - Foundation and application of generalized mixed FEM towards nonlinear problems in solid mechanics

Supervisor:

P. Wriggers

Researcher:

T. Steiner

Brief description:

The research of this project aims at the mathematical foundation and the engineering application of generalized mixed FEM as well as the development and the analysis of new non-standard methods that yield guaranteed results for nonlinear problems in solid mechanics including finite deformations and nonlinear material.

 

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Multiscalemodelling/ Multiphysics

Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers

Bild zum Projekt Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers

Supervisor:

P. Wriggers, J. J. Rimoli

Researcher:

A. B. Harish, A. B. Shah

Brief description:

The work was done in collaboration with Mrs. Aarohi B. Shah and Dr. Julian J Rimoli of School of Aerospace Engineering, Georgia Tech, USA. In this work, we investigate non-crystallizing nanoparticle-reinforced polymers. The effects of the interface rubber between elastomeric matrix and filler particles and its alteration are investigated as a primary cause of Mullins and Payne effect.

 

details

 

Towards multiscale modeling of Abrasive wear

Bild zum Projekt Towards multiscale modeling of Abrasive wear

Supervisor:

P. Wriggers

Researcher:

A. B. Harish

Brief description:

The work is motivated towards understanding wear as a multiscale-multiphysics approach. A 3D framework is developed to simulate cracks propagation in a microstructure due to contact loading to eventually predict wear trends in filled elastomeric compounds.

 

details

 

Multi-Fluid Simulations for High Density Ratios

Bild zum Projekt Multi-Fluid Simulations for High Density Ratios

Supervisor:

P. Wriggers, B. Avci

Researcher:

J.-P. Fürstenau

Brief description:

Although the contact between fluids or gases of different densities is a common event in nature, like the interaction of water and air, the simulation of multiple fluids often comes along with numerous problems. With the Lagrangian description of continuous fluids in terms of the Smoothed Particle Hydrodynamics (SPH) method multi-fluid interactions within the particle scale can simulated. Nevertheless with the standard SPH algorithms multi-fluid problems can not be solved because of the density jumps at the interfaces. Within the project the state of the art of current multi-fluid approaches are compared and evaluated to develop appropriate methods for the simulation of multi-fluid systems with high density ratios.

 

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Homogenization procedures for coupled thermo-chemo-mechanical problems

Bild zum Projekt Homogenization procedures for coupled thermo-chemo-mechanical problems

Supervisor:

P. Wriggers, E. Baranger

Researcher:

Jin Man Mok

Brief description:

In order to understand processes of continuum damage mechanics it is necessary to investigate thermo-chemo-mechanical coupled processes at micro scale. However for engineering purposes it is still necessary to be able to model these processes at macro scale, especially when large structures have to be designed. Thus a homogenization procedure or a FE^2 framework is necessary to transform the relation, describing the coupled thermo-chemo-mechanical response at micro scale to the macro scale. The related equations and procedures have to be developed and implemented in a finite element software system.

 

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Direct Numerical Simulation of Multiphase Flows

Bild zum Projekt Direct Numerical Simulation of Multiphase Flows

Supervisor:

P. Wriggers

Researcher:

B. Avci

Brief description:

Multiphase flows consisting of a continuous fluid phase and a dispersed phase of macroscopic particles are present in many engineering applications. In general, a main task in the study of the particle-laden fluid flow of an application is to make predictions about the system's nature for various boundary conditions, since, depending on the volume fraction and mass concentration of the dispersed phase a fluid-particle system shows quite different flow properties. Unfortunately, often it is impossible to investigate such a system experimentally in detail or even at all. An option to capture and to predict its properties is performing a direct numerical simulation of the particulate fluid. For this purpose, an efficient approach is developed in this project by coupling the discrete element method and finite element method.

 

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Multiscale Method for Hydro-Chemo-Thermo-Mechanics Coupling due to Alkali Silica Reaction in Concrete

Bild zum Projekt Multiscale Method for Hydro-Chemo-Thermo-Mechanics Coupling due to Alkali Silica Reaction in Concrete

Supervisor:

P. Wriggers

Researcher:

T. Wu

Brief description:

Alkali Silica Reaction(ASR) is one of most determinant reasons leading to the deterioration of concrete structures, which can be ascribed to the expansion of gel produced by ASR in the microstructural level of concrete. The challenge in the modeling of ASR is due to the necessity to take into account the presence of heterogeneities and physical processes distributed over multiple length scales. With increasing computation power and the tomography scan technology, it can be implemented by numerical simulation . In this contribution, 3D multiscale hydro-chemo-thermal-mechanical coupling based on a staggered method is demonstrated, which explicitly describes the damage evolution originating from the chemical reaction in the microscale and the dependence on environmental factors.

 

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RAMWASS - Integrated Decision Support System for Risk Assessment and Management

Bild zum Projekt RAMWASS - Integrated Decision Support System for Risk Assessment and Management

Supervisor:

P. Wriggers

Researcher:

B. Avci

Brief description:

The objective of the EU-project RAMWASS is to develop and validate a new decision support system (DSS) for the risk assessment and management for the prevention and/or reduction of the negative impacts caused by human activities on the water/sediment/soil system at river basin scale in fluvial ecosystems.

 

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Numerical modeling of electrical contacts

Bild zum Projekt Numerical modeling of electrical contacts

Supervisor:

P. Wriggers

Researcher:

C. Weißenfels

Brief description:

The focus of this work is the investigation of the behavior in electrical contacts, where electrical, thermal and mechanical fields are coupled. Specifically, theoretical constitutive models for the electrical conductance and electrical wear phenomena are developed and implemented in a three dimensional finite element setting. Also a new relation for wear is proposed, where the amount of wear is coupled to the dissipation arising at the contact interface.

 

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MULTIPHYSICS COMPUTATIONAL HOMOGENIZATION METHODOLOGIES

Bild zum Projekt MULTIPHYSICS COMPUTATIONAL HOMOGENIZATION METHODOLOGIES

Supervisor:

P. Wriggers, I. Temizer

Brief description:

Computational homogenization techniques that are amenable to a multiscale implementation are being developed for multiphysics problems at the finite deformation regime. Applications include the estimation of the contact conductance for rough interfaces and the modeling of the coupled thermomechanical response of heterogeneous materials.

 

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Biomechanics

Computational modeling of in-stent restenosis

 

Supervisor:

M. Marino

Funded by:

Masterplan SmartBiotecs, MWK (Lower Saxony, Germany)

Brief description:

This project aims to develop a computational tool for the modeling of the long-term behaviour of stent deployment, with a special focus on both current and prospective approaches. A multiscale description of arterial constitutive behaviour will be employed, including possible damage due to the stenting procedure. Moreover, the chemo-biological mechanisms underlying the growth and remodelling due to wound healing in tissues will be introduced. Therefore, a multiphysics computational framework will be developed and applied for the analysis of both metal and drug-eluting stents. The project will allow to identify the dominant mechanisms driving in-stent restenosis, deciphering the role of the different molecular species in the pathological remodeling of arteries. The final target is to optimise the clinical outcome of current approaches and propose targeted therapeutic approaches.

 

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Patient-Specific FSI Analysis of the Blood Flow in the Thoracic Aorta

Bild zum Projekt Patient-Specific FSI Analysis of the Blood Flow in the Thoracic Aorta

Supervisor:

P. Wriggers, B. Avci

Researcher:

B. Avci

Brief description:

The complexity of numerical modeling and simulation of blood flow in patient-specific thoracic aorta geometries leads to a number of major computational challenging issues. For instance, for an adequate simulation of the flow and pressure field, the incompressible Navier-Stokes equations have to be solved with the assumption that the relatively thin blood vessels suffer large displacements and undergo large elastic or visco-elastic deformations caused by the pulsatile blood flow. Subsequently, inaccurate predictions would be obtained for the hemodynamic quantities with the very simplifying rigid-wall assumption (CFD modeling). Moreover, when applying only the CFD modeling approach the essential phenomena of pressure wave propagation in cardiovascular systems are disregarded, however these phenomena are of major relevance for clinical practice. Accordingly, strongly coupled FSI schemes are inevitable for comprehensive blood flow simulations in arterial systems, and as blood and vascular walls have comparable densities, monolithic or at least partitioned strongly coupled FSI schemes are required for solving the multi-physics problem with its inherent significant added-mass effects.

 

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Interfacial effects and ingrowing behaviour of magnesium-based foams as bioresorbable bone substitute material

Bild zum Projekt Interfacial effects and ingrowing behaviour of magnesium-based foams as bioresorbable bone substitute material

Supervisor:

P. Wriggers

Researcher:

A. Krüger

Funded by:

DFG

Brief description:

Within this project sponge-like structures made of magnesium alloys are being developed and investigated as bone-replacement material. The advantage of magnesium is that it naturally occurs in the body and that it degrades gradually. The developed implants will be investigated regarding to the occurring interface effects in cooperation with the Institute of Material Science of the Leibniz University Hanover and the Surgical and Gynaecological Small Animal Clinic of the Ludwig-Maximilians-University Munich. Finite element methods are extensively used for the development and investigation of the sponges. Based on in vitro and in vivo results the simulation model will be build up and validated. The simulation model includes the interface effects, like degradation of the implant and ingrowth behaviour of the bone into the sponge structure. The change of the mechanical properties during the degradation has to be considered in the simulations.

 

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Gekoppelte Simulation von Aerosolströmungen in asthmatischen Bronchien

Bild zum Projekt Gekoppelte Simulation von Aerosolströmungen in asthmatischen Bronchien

Supervisor:

P. Wriggers, B. Avci

Researcher:

J. Stasch, J.-P. Fürstenau

Funded by:

Leibniz Universität Hannover, Wege in die Forschung

Brief description:

Das Ziel dieses Projektvorhabens ist es, auf Basis eines gekoppelten 3D Mehrfeldmodells die partikelbeladene Luftströmung in gesunden sowie in asthmatisch verengten Bronchien anhand von numerischen Simulationen zu studieren.

 

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Advanced multiscale computational mechanics for physiopathological behavior analysis of tissues and organs

Bild zum Projekt Advanced multiscale computational mechanics for physiopathological behavior analysis of tissues and organs

Supervisor:

P. Wriggers, M. Marino

Funded by:

Alexander von Humboldt-Stiftung

Brief description:

The physiological functionalities of large biological structures are highly affected by the mechanics of living tissues which is, in turn, related to microstructural arrangement of histological constituents and biochemical environment at nanoscale. Present research activity aims to develop a novel tissue multiscale description, including also inelastic mechanisms, coupled with an advanced computational formulation under finite strain and large-displacement assumptions. As a result, an innovative in-silico tool for simulation of organs and large biological structures will be developed, allowing to predict pathology-related damage or pharmacological-related healing and providing novel diagnostic and clinical indications for highly patient-specific medical treatments.

 

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High Performance Computing (HPC)

Bild zum Projekt

Supervisor:

P. Wriggers, B. Avci

Researcher:

B. Avci

Funded by:

FP7 of the EU

Brief description:

In many cases, massive parallel large-scale computations are indispensable for solving problems of practical interest. The numerical treatment of such class problems requires not only highly efficient scalable parallel solvers, moreover, efficient parallel algorithms covering the whole simulation pipeline – also including pre- and post-processing, mesh generation and design solvers considering uncertainties – are essential to model and to simulate large-scale or exascale class problems. The specific goal of this project is therefore the development and implementation of new parallel algorithms and methods that will allow to solve large-scale class problems with high efficiency.

 

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Fracture Mechanics/ XFEM

Nanoindentation for material property characterization

Bild zum Projekt Nanoindentation for material property characterization

Supervisor:

P. Wriggers, S. Löhnert

Researcher:

A. B. Harish, V. Kruppernikova

Brief description:

In this work, techniques are developed for nanoindentation of soft polymers and brittle powdery materials and measurement of properties like modulus, hardness and fracture toughness.

 

details

 

Large Deformation Cohesive-Zone Element for Fracture in Rubbery Polymers

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

Supervisor:

P. Wriggers

Researcher:

A. B. Harish

Brief description:

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

 

details

 

Crack propagation and crack coalescence in a multiscale framework

Bild zum Projekt Crack propagation and crack coalescence in a multiscale framework

Supervisor:

S. Löhnert, P. Wriggers

Researcher:

M. Holl

Brief description:

In this project a numerical framework for propagating and intersecting cracks on micro and macro scales is set up. Modeling cracks using the eXtended Finite Element Method (XFEM) provides an accurate and efficient numerical framework to model propagating and intersecting cracks. Since cracks of different length scales are assumed, a multiscale method is applied in order to be numerical efficient.

 

details

 

Virtual Design

Numerical Algorithms for Machining and Cutting Processes – Improvement of Accuracy and Efficiency

Bild zum Projekt Numerical Algorithms for Machining and Cutting Processes – Improvement of Accuracy and Efficiency

Supervisor:

C. Weißenfels, P. Wriggers

Researcher:

M.Sc. Dengpeng Huang

Funded by:

China Scholarship Council (CSC)

Brief description:

Metal cutting is one of the most common machining processes in industrial production. Modeling of metal cutting has proved to be particularly complex due to the coupled physical phenomena, including high dynamic shear, fracture, contact, friction and heat-generation. Analytical modeling based on machining experiment has been investigated extensively, but it can only describe the material behavior qualitatively. With the advent of high-speed computer and related robust algorithms, numerical modeling becomes a useful approach to improve and clearly understand the machining processes. In the current work, the Optimal Transportation Meshfree (OTM) method is used to simulate the material removal process in metal cutting.

 

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