Institute of Continuum Mechanics - Biomechanics
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Logo: Institute of Continuum Mechanics/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institute of Continuum Mechanics/Leibniz Universität Hannover
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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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Simulation of atherosclerotic plaque impact on the red blood cells dynamics in arteries

Bild zum Projekt Simulation of  atherosclerotic plaque impact  on the red blood cells dynamics  in arteries

Supervisor:

P. Wriggers

Researcher:

M.R.Hojjati

Funded by:

DAAD

Brief description:

Atherosclerosis, a coronary disease, is one of the main cause of mortality in the many countries. Atherosclerosis emerges as a results of hardening and narrowing of the blood vessels , caused by the gradual accumulation of deposits on the inside of arteries walls. This finally leads to atherosclerotic plaque. In this work, The impact of atherosclerotic plaque on red blood cells (RBC) dynamics in the blood vessels is studied. A fluid-solid interaction (FSI) analysis is developed. For the fluid phase, a mesh-less Lagrangian method is adopted which is called smoothed particle hydrodynamics (SPH). RBCs are considered to be the solid phase and are assumed to behave like deformable solid floated in the blood. A strong two way coupling is developed in the context of immersed boundary method (IBM) to capture the accurate fluid-solid interaction.

 

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Numerical Simulation and Experimental Validation of Biofilm Growth

Bild zum Projekt Numerical Simulation and Experimental Validation of 
Biofilm Growth

Supervisor:

P. Wriggers , M. Stiesch

Researcher:

M. Soleimani

Brief description:

Biofilms are bacterial colonies growing on solid-fluid interfaces, wherever enough dissolved nutrients are available. Their formation is a complex process in the sense that several Physical phenomena (Reaction-Diffusion-Advection, Sedimentation, Erosion, Fluid-Solid-Interaction) are coupled and consequently different time-scales are involved. In this project, the focus is on the biofilm formation in a flow chamber which resembles the mouth cavity in the vicinity of dental implants. The goal is to develop a computational tool capable of simulating the biofilm growth. Numerical solution of the Navier–Stokes equation in domains with complex boundaries that dynamically change as a result of biological diffusion-reaction, detachment and sedimentation in biofilm growth presents a very serious challenge to grid-based methods. In this project, a fully Lagrangian particle approach(mesh-less method) based on smoothed particle hydrodynamics (SPH) is developed.

 

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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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