Publicação
Evaluation of quasi-static and fatigue properties of cement-bone bonded joints under pure-mode I and II loading: numerical and experimental characterization
| Resumo: | Bone is a material with a complex, anisotropic, hierarchical and heterogeneous microstructure, which gives it a remarkable mechanical performance. However, as it is sometimes exposed to very adverse demands resulting from the interaction with the environment, it tends to develop damage, culminating in fracture. Fractures in long bones sometimes result from fatigue loads during numerous daily activities. These fractures reduce the quality of life of human beings and entail high costs for the health system. Over the years, techniques have been developed that have allowed for the stabilization of bone fractures. Currently, metal osteosynthesis plates are widely used to repair fractures, despite being a very invasive technique that depends on the stability of the fixation and the plate-bone-screw interfaces. To innovate and improve the treatment systems for complex fractures of the long bones of the human body, the BoFraPla project emerged, which proposes to develop a system for anchoring bone aggregates through a fibrous system, ensuring immobilization and alignment of bone segments, providing adequate vascularization of damaged tissues. One of the development phases of this innovative biomedical system consists of studying the connection of the bone to bone cement, necessary for the fixation of the fibrous system. For this purpose, within the scope of the activities of this project, the present dissertation aims at the mechanical, experimental and numerical characterization of the connection of cortical bone to polymethylmethacrylate (PMMA) cement composition. In this sense, samples of bonded joint (bone-cement) were manufactured with DCB configurations for pure mode I and ENF for pure mode II. These specimens were later submitted to static fracture and fatigue tests to evaluate fracture properties in those failure modes and fatigue parameters that enable their characterization in this demand mode. The experimental results thus obtained were later used in cohesive damage initiation and propagation models using the Finite Element Method. Finally, it was possible to validate the tests carried out to determine the adequate specimen dimensions, to predict the mechanical behaviour of bone fracture reinforcement systems using bone cement, i.e., the validation of the developed protocol. |
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| Autores principais: | Campos, Teresa Daniela Azevedo |
| Assunto: | Cement-cortical bone bonded joint Fracture and fatigue test Modified Paris law Mixed mode cohesive damage law I+II Finite element method Junta colada cemento-osso cortical Ensaios de fratura e de fadiga Lei de Paris modificada Lei de dano coesivo de modo misto I+II Método dos elementos finitos |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Bone is a material with a complex, anisotropic, hierarchical and heterogeneous microstructure, which gives it a remarkable mechanical performance. However, as it is sometimes exposed to very adverse demands resulting from the interaction with the environment, it tends to develop damage, culminating in fracture. Fractures in long bones sometimes result from fatigue loads during numerous daily activities. These fractures reduce the quality of life of human beings and entail high costs for the health system. Over the years, techniques have been developed that have allowed for the stabilization of bone fractures. Currently, metal osteosynthesis plates are widely used to repair fractures, despite being a very invasive technique that depends on the stability of the fixation and the plate-bone-screw interfaces. To innovate and improve the treatment systems for complex fractures of the long bones of the human body, the BoFraPla project emerged, which proposes to develop a system for anchoring bone aggregates through a fibrous system, ensuring immobilization and alignment of bone segments, providing adequate vascularization of damaged tissues. One of the development phases of this innovative biomedical system consists of studying the connection of the bone to bone cement, necessary for the fixation of the fibrous system. For this purpose, within the scope of the activities of this project, the present dissertation aims at the mechanical, experimental and numerical characterization of the connection of cortical bone to polymethylmethacrylate (PMMA) cement composition. In this sense, samples of bonded joint (bone-cement) were manufactured with DCB configurations for pure mode I and ENF for pure mode II. These specimens were later submitted to static fracture and fatigue tests to evaluate fracture properties in those failure modes and fatigue parameters that enable their characterization in this demand mode. The experimental results thus obtained were later used in cohesive damage initiation and propagation models using the Finite Element Method. Finally, it was possible to validate the tests carried out to determine the adequate specimen dimensions, to predict the mechanical behaviour of bone fracture reinforcement systems using bone cement, i.e., the validation of the developed protocol. |
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