Title: Quantification of microdamage formation during fatigue testing of individual trabeculae - II
Language: English
Authors: Kabbani, Omar 
Keywords: Knochen; Mechanische Eigenschaften; Bone; Mechanical Properties
Advisor: Thurner, Philipp  
Issue Date: 2020
Number of Pages: 69
Qualification level: Diploma
Osteoporosis is a skeletal disease which decreases the bone mass density and has a big effect on humans’ health all over the globe. There is no agreement on the disease diagnosis or treatment. However, the importance of bone quality is not questioned. Microdamage accumulation might have an effect on the decrease of mechanical properties of osteoporotic bones. Considering that most of the fractures due to osteoporosis are located in trabecular bone regions and that most of the existing researches focus on cortical bone or whole trabecular bone cores, it is of interest to develop a mechanical test procedure that allows testing on individual trabeculae. This project improves the mechanical test protocol developed by Julia Fischer. Modifications in order to make the protocol more sample independent and better controlled in terms of load conditions. Due to individual trabecula’s dimensions and shape diversity the number of different conditions and variables is considerable, which implies that a compromise between precision and practicality has to be found. A difference in mechanical properties presented by two different specimens of the same race and age was observed and a solution is given. The importance of the relaxation of the sample during the test is discussed and practically removed. Other improvements were applied and the result is a protocol which allows fatigue testing on individual trabeculae controlling the load conditions during the whole test. A decrease of Young’s modulus with increasing accumulated number of cycles is observed using this protocol. Some issues concerning the fluorescent labelling of microdamage was detected and is discussed in this thesis. The resulting protocol of this thesis is still very time consuming and the success rate (successfully tested samples / total attempts of sample obtainment) is very low. Thus, an alternative for the used sample preparation is suggested. Although, due to time reasons it could not be applied and tested, but finite element simulations are cause for optimism. This modification would radically change the sample preparation reducing the elapsed time and increasing the success rate.
URI: https://doi.org/10.34726/hss.2020.69315
DOI: 10.34726/hss.2020.69315
Library ID: AC15679985
Organisation: E317 - Institut für Leichtbau und Struktur-Biomechanik 
Publication Type: Thesis
Appears in Collections:Hochschulschrift | Thesis

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