Development of a computational thrombus model using finite element software LS-DYNA

Master thesis (2022)

Authors

S.C.M. Overschie Mechanical Engineering

Contributors

G. Luraghi Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 1)
F.J.H. Gijsen Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 2)
Mohammad J. Mirzaali Biomaterials & Tissue Biomechanics - Mechanical, Maritime and Materials Engineering (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2022 Serena Overschie
Finite Element Analysis LS-DYNA Thrombus mechanics
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Published Date

23-02-2022

Language

English

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Faculty

Mechanical Engineering

Abstract

An acute ischemic stroke is one of the leading causes of death and is caused by a thrombus that occludes a cerebral artery. This thrombus reduces the cerebral blood flow and causes irreversible brain tissue damage. Mechanical thrombectomy is a safe and effective technique to remove the thrombus from the cerebral arteries and restore the brain's blood flow. The mechanical properties of the thrombus highly influence the success rate of mechanical thrombectomy. To investigate the mechanical behavior of the thrombus under different loading conditions, numerical simulations could be performed. The aim of this thesis is to develop an in silico thrombus model to investigate the mechanical behavior of the thrombus under compressive and tensile loading conditions using finite element analysis software LS-DYNA. Experimental data collected from the lab is used to describe the mechanical behavior in the numerical thrombus models.

The building process of the in silico models in this study is organized in three parts. Part one is the cube model, where the material properties and numerical stable settings are investigated. Also, a combination of compression and tension is applied to the cube model to capture both the compressive and tensile forces present during mechanical thrombectomy. Part two includes geometry models that mimic the clot analog samples' geometry used during the experimental compression and tensile tests. Part three includes a clot analog with an initial hole in the middle to understand the fracture behavior of the thrombus. Different approaches to model fracture of the thrombus are investigated.

Three different parts characterize this thesis, and each includes a method, results, and discussion section. The discussion section of each part is dedicated to the decisions that have been made in that specific chapter. A discussion section is also included in the chapter Experiments. The general discussion at the end of this study will include the findings of each model and the comparison with literature. Recommendations for further research are given at the end.

In conclusion, this study provides a framework for modeling the thrombus under tensile and compressive loading, where the thrombus is modeled as a hyperelastic material. Future work is advised to extend and improve the models developed in this study.