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Logo: Institut für Baumechanik und Numerische Mechanik/Leibniz Universität Hannover
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Logo: Institut für Baumechanik und Numerische Mechanik/Leibniz Universität Hannover
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Experimental Characterization of Mechanical Properties of Rubber

Bild zum Projekt  Experimental Characterization of Mechanical Properties of Rubber

Bearbeitung:

ext. M. Dämgen, R. Schuster (German Institute of Polymer Systems (DIK))

Kurzbeschreibung:

The large strain mechanical response of rubber materials is investigated by experimental techniques. For a collective of well defined rubber systems stress softening, quasi-static hysterics, are studied by tension and compression tests. Additional experiments are performed regarding relaxation behaviour, anisotropic damage of the filler network, temperature dependency etc.

 

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A finite element tire modelling approach for car interior noise simulation

 

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, Dipl.-Ing Raffeala Chiarello

Kurzbeschreibung:

A finite element approach for the simulation of the dynamic behaviour of tires rolling on rough roads for the car indoor noise prediction is presented. Based on a detailed finite element model valid for the nonlinear stationary rolling analysis a modal tire model to be coupled with a total vehicle dynamics simulation approach has been developed, where special care is taken on the physical consistency.

 

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A micro-mechanically motivated approach for modelling the oxidative aging process of elastomers

 

Leitung:

Prof. Dr.-Ing. Udo Nackenhorst in collaboration with Dr. Markus Andre

Bearbeitung:

Darcy Beurle

Laufzeit:

2016-2019

 

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A multi-scale approach on the transient dynamics of rolling tires

Bild zum Projekt A multi-scale approach on the transient dynamics of rolling tires

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Anuwat suwannachit

Förderung durch:

This work is supported by German Ministry for Economics within the “Leiser Straßenverkehr 2” program

Kurzbeschreibung:

The transient dynamic response of rolling tires, which is a major source of traffic noise nowadays, is excited from the tread impact and the road surface texture. A multi-scale approach is introduced in order to investigate the behaviour of tread rubber in contact with rough road surface at a sufficient small length-scale, which leads to the vibration of the overall structure.

 

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A Stochastic Approach on Stress Adaptive Bone Remodeling

Bild zum Projekt A Stochastic Approach on Stress Adaptive Bone Remodeling

Bearbeitung:

Maximilian Bittens, M.Sc.; Prof. Dr.-Ing. Udo Nackenhorst

Kurzbeschreibung:

In this project the uncertainties in stress adaptive bone remodeling are addressed. Accounting for these uncertainties stochastic techniques like Polyomial Chaos Expansion or Stochastic Collocation Methods are used in order to build a stochastic response surface for evaluating the stochastic properties, e.g. sensitivity, of the system.

 

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ALE-interface coupling for multiscale analysis of treaded tires in rolling contact

Bild zum Projekt ALE-interface coupling for multiscale analysis of treaded tires in rolling contact

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, Dip.-Ing. Raffaela Chiarello, Dipl. Ing. (FH) Ole Stegen

Kurzbeschreibung:

The Arbitrary Lagrangian Eulerian (ALE) formulation is well established for the finite element simulation of stationary as well as transient dynamics rolling contact phenomena. The method enables mesh refinements in the contact zone and a time independent formulation of stationary rolling. The inconvenience for the simulation of rolling tires is the incorrect treatment of the tread blocks due to the non axisymmetric geometry.

 

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An efficient approach for modeling hip joint contact

Bild zum Projekt An efficient approach for modeling hip joint contact

Bearbeitung:

M.Sc. Kristin Fietz, Prof. Dr.-Ing Undo Nackenhorst

Förderung durch:

This research is supported by the German Research Foundation under Grant NA 330/6-1.

Kurzbeschreibung:

In developed countries osteoarthritis is the major cause for artificial joint replacement. Unfortunately, the formation processes of this degeneration of cartilage and subchondral bone remain partly unknown. In this research project a three dimensional finite element model of the hip joint is developed in order to investigate the fluid cartilage contact under physiological loading conditions.

 

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Bone Cell Simulations using Tensegrity Structures

Bild zum Projekt Bone Cell Simulations using Tensegrity Structures

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, Dipl.-Ing. (FH) Dieter Kardas, ext. IIya Arsenyev, Oleg Khromov

Kurzbeschreibung:

Bone quality detoriates with time, therefore it has to renew itself throughout the life. This process is called bone remodeling. It is well accepted, that osteocytes are the sensor cells for this process.

 

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Computational mechanics in terms of mixed aleatory and epistemic uncertain random fields

Bild zum Projekt Computational mechanics in terms of mixed aleatory and epistemic uncertain random fields

Bearbeitung:

Mona Madlen Dannert

Förderung durch:

Priority Programme SPP 1886 of German Research Foundation (DFG), State of Lower Saxony

Kurzbeschreibung:

This project investigates probability box (p-box) approach including probabilistic and possibilistic aspects. This way, both kind of uncertainties - aleatory and epistemic - can be considered within a random field.

 

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Computational Methods for Frictional Rolling Contact

Bild zum Projekt Computational Methods for Frictional Rolling Contact

Bearbeitung:

ext. M. Ziefle

Förderung durch:

This work is financed by the German Research Foundation (DFG), research group FOR492.

Kurzbeschreibung:

The aim of this research project is the development of efficient computation methods for the analysis of frictional rolling contact problems of elastomer solids on rigid surfaces.

 

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Computational simulation of piezo-electrically stimulated bone adaption surrounding activated tooth implants

Bild zum Projekt Computational simulation of piezo-electrically stimulated bone adaption surrounding activated tooth implants

Bearbeitung:

M. Sc. Seyed Alireza Shirazi Beheshtiha, Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

State of Lower Saxony

Kurzbeschreibung:

This study aims for the development of active implants which provide additional electrical stimulation for bone adaption. A computational framework is presented in order to optimize new developments for activating dental implants with piezoelectric coatings.

 

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Computational techniques for the stochastic excitation of rolling tires from rough road surface contact

Bild zum Projekt Computational techniques for the stochastic excitation of rolling tires from rough road surface contact

Bearbeitung:

Robert Lee Gates, M.Sc.; Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

DFG (German Research Foundation)

Kurzbeschreibung:

In this project, we intend to address issues in modeling rolling tires on rough road surfaces by (a) extending previously developed methods by a stochastic excitation function describing the interaction of the macroscopic tire model and the detailed meso-mechanical contact behavior of the tire tread with the road surface; (b) including dynamic stiffening effects in the rubber compound.

 

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Concepts for Chemical Degradation of Materials and Structures

Bild zum Projekt Concepts for Chemical Degradation of Materials and Structures

Bearbeitung:

Dipl.-Ing. Milena Möhle, Prof. Dr.-Ing. Udo Nackenhorst

Kurzbeschreibung:

The degradation of materials is of great importance especially when they are expected for a long service time or when it is not easily accessible for maintenance, for example like natural gas pipelines.

 

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Constitutive modeling of rubber behavior in a broad frequency domain

Bild zum Projekt Constitutive modeling of rubber behavior in a broad frequency domain

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Anuwat Suwannachit

Förderung durch:

This work is supported by German Ministry for Economics within the “Leiser Straßenverkehr 2” program

Kurzbeschreibung:

Mechanical response of technical rubber is usually described by damage and hysteresis behaviour under quasi-static cyclic loading conditions, while dynamic stiffening and viscous effects are predominant for high frequency analysis. For the computation of rolling tire behaviour with questions regarding safety, comfort and sound radiation a constitutive description incorporating all of these effects is needed.

 

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Development of a numerically robust material model for rock salt

Bild zum Projekt Development of a numerically robust material model for rock salt

Bearbeitung:

M. Eng. Mathias Grehn, Prof. Dr.-Ing. Udo Nackenhorst

Kurzbeschreibung:

Around 300000 tons of high-level radioactive waste exists on earth and around 12000 tons of high-level radioactive waste will be added every year. Possible solutions for storage of radioactive waste are salt domes as reservoirs for toxic and nuclear waste.

 

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Dynamic properties of heterogeneous materials with uncertain microstructures and local damage

 

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Andre Hürkamp

Kurzbeschreibung:

The goal of this research project is the development of novel predictive techniques for damage monitoring in heterogenous materials. Multi-scale modeling techniques are combined with related statistical methods for scale bridging.

 

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FE-Analysis of Osteons concerning the Mechanosensation of Bone Material

 

Bearbeitung:

ext. C.Lenz

Förderung durch:

This work is supported by the Graduiertenkolleg 615 of the DFG (German Research Foundation)

Kurzbeschreibung:

The aim of this project is to localize the detection mechanism of external loads in bone tissue and simulate the formation of new osteons.

 

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Finite Element Analysis of Hip Joint Contact

Bild zum Projekt Finite Element Analysis of Hip Joint Contact

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Kristin Fietz, M.Sc. Andre Lutz

Kurzbeschreibung:

Diseases and injuries of the human muscosceletal system are of particular importance in the health care systems worldwide. The overall costs in Germany including loss of production are estimated up to 100 billion Euros every year.

 

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Finite Element Analysis of the Fracture Healing Process

Bild zum Projekt Finite Element Analysis of the Fracture Healing Process

Bearbeitung:

Prof. Dr.-Ing. U. Nackenhorst, M.Sc. Alexander Sapotnick

Förderung durch:

This project is funded by the DFG (German Research Foundation) NA-330/8-1

 

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Finite Element Evaluation of Primary Stability of Teeth Implants

Bild zum Projekt Finite Element Evaluation of Primary Stability of Teeth Implants

Kurzbeschreibung:

Usually dental implants are loaded after the healing period which is generally 2 to 3 months after the insertion of the implant. During the healing period the patient is dependent on liquid diet. Therefore implant technologies are heading towards implants that can be loaded directly after insertion. The aim of this project is to compare the primary stability of two dental implants, one standard model and one model with a bar for rotational stabilization.

 

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Finite Element Simulation of Osseointegration of Uncemented Endoprostheses

Bild zum Projekt Finite Element Simulation of Osseointegration of Uncemented Endoprostheses

Bearbeitung:

Prof. Dr.-Ing. U. Nackenhorst, M.Sc. André Lutz

Kurzbeschreibung:

The term osseointegration means the ingrowth of bone into a porous coated implant. In order to simulate the osseointegration of bone implants, a bio-active interface theory is necessary.

 

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Image reconstruction / finite element modelling

Bild zum Projekt Image reconstruction / finite element modelling

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Andre Lutz

Kurzbeschreibung:

Due to the complex structure of bone it is very difficult to get geometry data for the generation of simulation models. In addition it is impossible to get patient-specific geometry data for patient-specific treatment. With this program it is possible to extract geometry data from CT datasets and generate finite element models. Furthermore it is possible to map bone density information on the created finite element model for the purpose of calculating statically equivalent load sets.

 

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Innovative concepts for physically based modeling approaches of high-cycle fatigue

 

Leitung:

Prof. Dr.-Ing. Udo Nackenhorst in collaboration with Prof. David Neron (LMT, ENS Cachan) and Prof. em. Pierre Ladeveze (LMT ENS Cachan) in the framework of IRTG 1627

Bearbeitung:

Mainak Bhattacharyya, Dr.-Ing. Amelie Fau

Laufzeit:

2014-2017

Förderung durch:

International Research Training Group 1627, DFG (German Research Foundation)

Kurzbeschreibung:

The objective of this project is to go beyond S-N curves classically used to represent damage evolution for damage fatigue. Original sophisticated integration schemes are investigated to be able to predict damage evolution for a high number of cycles while considering physically based models.

 

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Investigations on the Numerical Solution of the Fokker-Planck Equation with Discontinuous Galerkin Methods

 

Bearbeitung:

Prof.Dr.-Ing. U.Nackenhorst, Dipl.-Ing. F. Loerke

Kurzbeschreibung:

As the probability density distribution is an appropriate measure for comprehensive description of stochastic processes, the derivation and solution of transport equations for the probability density requires particular attention. Examination of nonlinear dynamic systems under uncertain excitation or with uncertain parameters leads to stochastic equations of motion.

 

 

Model Reduction Techniques for Probabilistic Fatigue Assessment

 

Leitung:

Prof. Dr.-Ing. Udo Nackenhorst in collaboration with Prof. David Neron (LMT, ENS Cachan) and Prof. em. Pierre Ladeveze (LMT ENS Cachan) in the framework of IRTG 1627

Bearbeitung:

Shadi Alameddin, Dr. Ing. Amelie Fau, Mainak Bhattacharyya

Laufzeit:

2016-2019

Förderung durch:

International Research Training Group 1627, DFG (German Research Foundation)

Kurzbeschreibung:

This project aims to develop reliable model reduction techniques for the treatment of damage fatigue modeling in the framework of multiple time scales and probabilistic evaluation of service life of materials and structures.

 

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Modeling and numerical simulation for the prediction of the fatigue strength of air springs

Bild zum Projekt Modeling and numerical simulation for the prediction of the fatigue strength of air springs

Bearbeitung:

M. Sc. Niraj Kumar Jha, Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

Continental Teves AG

Kurzbeschreibung:

Fatigue failure of cord-reinforced rubber composite has been the subject of extensive studies in automotive industries due to its importance in engineering applications. The classical examples of such composites are found in tires, hoses, and airsprings.

 

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Modeling and Simulation of Rolling Tires with Detailed Tread Pattern

Bild zum Projekt Modeling and Simulation of Rolling Tires with Detailed Tread Pattern

Bearbeitung:

M. Sc. Thirumalalagu Palanichamy, Prof. Dr.-Ing. Udo Nackenhorst

Kurzbeschreibung:

The analysis of tires is of importance in tire industries for determining wear phenomena, endurance and noise effects, etc. The relative kinematics framework based on ALE formulation has its main advantages in implementing the detailed contact analysis with local mesh refinement and time independent formulation of elastic stationary rolling. The weak point of the ALE formulation is that tires with detailed tread pattern cannot be simulated due to its axi symmetric constraint.

 

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Modeling of electro-mechanical contact on a mesoscopic length-scale

Bild zum Projekt Modeling of electro-mechanical contact on a mesoscopic length-scale

Bearbeitung:

ext. T. Helmich

Förderung durch:

This work is supported by the Graduiertenkolleg 615 of the DFG (German Research Foundation).

Kurzbeschreibung:

The aim of the project is a simulation of the electro-mechanical coupled contact behaviour between tip and surface of an afm.

 

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Multiscale Modeling, with Applications in Contact Mechanics

 

Bearbeitung:

Prof.Dr.-Ing. U. Nackenhorst, Dr.-Ing W. Shan

Förderung durch:

Deutsche Forschungsgemeinschaft (DFG), Graduiertenkolleg 614 (GRK615)

Kurzbeschreibung:

We seek for multi-scale methods with physically consistent coupling of the molecular dynamics (MD) method and the finite element methods (FEM), and apply it to contact problems. The material near the contact region will be modelled in MD models so that complicated behaviours such as dislocations, initiation of plastic deformations and crack propagation can be captured.

 

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Non-linear theory and adaptive FEM of martensitic phase transformation with technical application

Bild zum Projekt Non-linear theory and adaptive FEM of martensitic phase transformation with technical application

Bearbeitung:

Prof.em.Dr.-Ing.habil. Dr.-Ing.E.h. Dr.h.c. mult. Erwin Stein, M.Sc. Gautam Sagar

Förderung durch:

This work is financed by the German Research Foundation (DFG Ste/51- 1 & 2).

Kurzbeschreibung:

The work concerns the micromechanical constitutive modelling, algorithmic implementation and numerical simulation of shape memory effect (SME) and superelastic effect for mono- and poly- crystalline shape memory alloys at fine strains.

 

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Numerical simulation of tire rolling noise radiation

 

Förderung durch:

Supported by BMBF

Kurzbeschreibung:

The structural dynamics of rolling tires is treated by a modal superposition approach whereas the underlying stationary rolling process is modeled within a nonlinear relative kinematics continuum theory.

 

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Numerical Treatment of Inelastic Constitutive Behaviour within an ALE-Framework of Rolling

Bild zum Projekt Numerical Treatment of Inelastic Constitutive Behaviour within an ALE-Framework of Rolling

Bearbeitung:

ext. M. Ziefle

Förderung durch:

This work is financed by the German Research Foundation (DFG).

Kurzbeschreibung:

The aim of this research project is the development of efficient computation methods for the treatment of inelastic material behaviour of rolling elastomer solids.

 

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Numerische Simulation probabilistischer Schädigungsmodelle mit der Stochastischen Finite Elemente Methode

 

Leitung:

Prof. Udo Nackenhorst

Bearbeitung:

Dr. Philipp-Paul Jablonski

Kurzbeschreibung:

Numerische Umsetzung diverser probabilistischer Methoden, u.a. Monte Carlo Simulation, Kollokationsmethode oder Polynomial Chaos, für die Berschreibung unsicherer Materialparameter innerhalb verschiedener Schädigungsmodelle in Verbindung mit der Finite Elemente Methode

 

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Reduced-order models for structural dynamic Finite Element systems

Bild zum Projekt Reduced-order models for structural dynamic Finite Element systems

Bearbeitung:

Stefanie Tegtmeyer, Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

State of Lower Saxony

Kurzbeschreibung:

Computational models from different engineering fields tend to get more and more detailed and complex thanks to the development of more and more powerful computers. Nowadays, solving these large systems of equations is not impossible, but requires a lot of time and computational resources.

 

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Sophisticated optimization techniques for structural health monitoring

Bild zum Projekt Sophisticated optimization techniques for structural health monitoring

Bearbeitung:

M. Sc. Mahmoud M. Jahjouh, Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

DAAD – Deutscher Akademischer Austauschdienst

Kurzbeschreibung:

Structural monitoring and damage detection has become a growing area in research and development, as witnessed by the increasing number of relevant journal and conference papers. To this end, a crucial challenge is the development of robust and efficient structural identification methods that can be applied to identify key parameters and hence, cause change of structural state.

 

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Stochastic Finite Elements

 

Bearbeitung:

Prof.Dr.-Ing. U. Nackenhorst, M.Sc. P.Jablonski

Kurzbeschreibung:

In vielen ingenieurtechnischen Anwendungen sind nicht deterministische Prozesse und/oder Parameter enthalten. die das Systemverhalten in erheblichen Maßen beeinflussen.

 

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Stochastic Modeling of Fatigue Processes

 

Leitung:

Prof. Dr. Ing. Udo Nackenhorst

Bearbeitung:

M. Sc. Wei Ran Zhang, Dr. Ing. Amelie Fau

Laufzeit:

2016-2019

Förderung durch:

International Research Training Group 1627, DFG (German Research Foundation)

 

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Studies on bone remodelling theory based on microcracks

Bild zum Projekt Studies on bone remodelling theory based on microcracks

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, Dipl.-Ing.(FH) Dieter Kardas

Förderung durch:

This work is supported by the Research training group 615 of the DFG (German Research Foundation)

Kurzbeschreibung:

Inside the cortical section of every bone, a remodelling cycle, including the resorption and build up of bone matrix, takes place. This phenomenon lasts for the life time. Research groups nowadays agree on the theory, that bone cells called osteocytes, lying inside the bone matrix, have the function as a sensor and are responsible for the remodelling behaviour – but still there is disagreement regarding to what is stimulating the cells.

 

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Studies on the biomechanical compatibility of hip-joint endoprostheses

 

Bearbeitung:

Prof.Dr.-Ing. Udo Nackenhorst, M.Sc. Andre Lutz, ext. B. Ebbecke

Kurzbeschreibung:

The biomechanical compatibility of different devices for artificial hip joint replacement is studied by use of computer simulation. Special emphasis is laid onto the bone remodelling caused from different prosthesis designs. Already these qualitative comparisons enables for rating the systems regarding their long term success.

 

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Theoretical and algorithmic concepts for description of demand-adaptive bone growth

Bild zum Projekt Theoretical and algorithmic concepts for description of demand-adaptive bone growth

Bearbeitung:

Prof.Dr.-Ing. Udo Nackenhorst, M.Sc. Andre Lutz, ext. B.Ebbecke

Förderung durch:

This work is in cooperation with the MHH (Medizinische Hochschule Hannover)

Kurzbeschreibung:

Computational techniques for the simulation of stress-adaptive bone-remodelling have been developed and applied for the analysis of the biomechanical compatibility of hip-joint endo-prothesis. Numerical simulations are in good agreement with clinical observations and enable parameter studies for the development of optimized prosthesis designs.

 

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Thermo-mechanical analysis of tires in stationary rolling contact

Bild zum Projekt Thermo-mechanical analysis of tires in stationary rolling contact

Bearbeitung:

M.Sc. Robert Beyer, Prof. Dr.-Ing. Udo Nackenhorst

Förderung durch:

German Research foundation (DFG)

Kurzbeschreibung:

The optimization of tire designs towards less rolling resistance and higher durability is still a challenging task. In the recently finished project (Link to Anuwat Suwannachit 2012) a thermo-mechanical framework for the calculation of the energy dissipation in the bulk material of stationary rolling tires was developed.

 

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Transient dynamic impact of inelastic solids with rough surfaces

Bild zum Projekt Transient dynamic impact of inelastic solids with rough surfaces

Bearbeitung:

Prof. Dr.-Ing. Udo Nackenhorst, M.Sc. Anuwat Suwannachit

Förderung durch:

This work is supported by German Research Foundation (DFG)

Kurzbeschreibung:

Since more than two decades a relative kinematic framework (ALE-description) has been widely used for rolling contact analysis of tire-road systems. The well known advantages of the ALE-formulation are the possibility of local mesh refinement in contact region and time-independent formulation of stationary elastic rolling.

 

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