|
|
Research study of mechanical properties of cranial tissue
Wojtek, Lukáš ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with the problematics of determining mechanical properties of cranial bone tissue. In this thesis a search study associated with an experimental determination of mechanical properties of bone tissues is executed. A brief history and progress of imaging methods and their importance of computation modelling are introduced. There are descriptions of histomorfometric parameters describing a structure of bone tissue at the micro level, ways of their computation and their impact on mechanical properties of bone tissue. Practical part of the thesis is focused on processing micro-CT images of cranial bone as well as analysing histomorfometric parameters (BV/TV, TbTh, TbSp) and subsequently stress strain analysis of selected sections of cranial bone tissue. Resulting Young´s modulus of elasticity of bone tissue [MPa] are compared with results from experiments from literature.
|
|
|
Biomechanical Study of Human Mandible in Physiological State
Borák, Libor ; Horyl, Petr (referee) ; Bartáková, Sonia (referee) ; Janíček, Přemysl (referee) ; Florian, Zdeněk (advisor)
This study deals with the mechanical aspects of human mandible in physiological state during the occlusion. The work is focused on evaluation of stress-strain conditions of bone tissue. The emphasis is paid to the interaction of teeth with the bone. In addition, contact pres-sures in temporomandibular joints during various loading conditions were determined. The analysis of material model of some parts of the system regarding their modelling-level is pre-sented as well. The problem concerning the evaluation of stress-strain states is solved by computational simulation using the finite element method. The presented work is a detailed analysis of the parts of the masticatory system and a thorough description of their modelling is presented. Special focus is paid to modelling of cancellous bone as well as of periodontal tissue which mediates the interaction between a tooth and the alveolar bone. Three-dimensional geometry of the mandible and all its teeth has been obtained by using the digitizing of real objects, namely by using of three-dimensional optical scanner. Three various modelling levels of the material of periodontium are assessed: Linear iso-tropic model, bilinear isotropic model and linear orthotropic model. Characteristics of these models are analyzed and especially nine new constants describing orthotropic model (which is almost absent in the literature) are proposed. Two-dimensional models are used for analysis of differencies in mechanical response of cancellous bone to the tooth loading. Two cases are considered: Cancellous bone as a ho-mogenous continuous model on one hand and with detailed trabeculous architecture model on the other. Computational model is divided into four basic cases varying in level of masticatory appa-ratus geometry: A – 2D geometry of bone; B – 3D geometry of bone segment with one tooth through three teeth; C – 3D geometry of whole mandible with the only tooth; D – 3D geome-try of whole mandible with all teeth. All basic cases are further researched in different varia-tions for different material models etc.
|
|
|
The role of imaging techniques in creation of computational models in biomechanics.
Prášilová, Eva ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
The first part of the bachelor´s thesis is dealt with the processing history of imaging techniques and their indications in a clinical practice. From point of view of the computer modeling, the computer tomography plays an important role in biomechanics. The second part of this treatment describes the scan processing of sections of two human mandible obtained from computer CT and micro-CT tomography. As a non-invasive way procedure can be characterized the image processing techniques, which analyze a bone density and BVF. The manual segmentation was applied in this analysis provided in ROI analysis software. There are shown the graphs of the bone densities of segments of two human mandibles depending on the specimen length and also there are compared the results of the measurements received from the CT and micro-CT tomography. Then follow the results illustrating the correlation of the relations and recalculations, which can be used as the determination tool of the mechanical properties of bone tissue. Finally there are described the computer models created in ANSYS focused on the different bone density analysis and stress strain analysis.
|
|
|
Biomechanical Study of Tooth Implants for Low Density Bone
Marcián, Petr ; Janíček, Přemysl (referee) ; Horyl, Petr (referee) ; Florian, Zdeněk (advisor)
This work deals with problem of dental implant area, where there are many problems at the dental implants application. The essential issue is the bone tissue quality at implant application, which sig-nificantly influences its deformation, tension and the possibility of subsequent implant failure. The knowledge of bone tissue mechanical properties of mandible and mandible with applied implant can significantly affect prediction of dental implant failure. The mechanical interaction can be described by variable determining deformation and tension of solved system. For this reason the computational modeling by using Finite Element Method was used for solving given problem. The computational model creation of solved system on the high resolution level is necessary for biomechanical assessment of implant failure, including bone tissue quality. For this purpose the biomechanical study was performed, which significantly spreads range of solved problem in this work afterwards. In this work the methodology, which describes assessment of bone tissue quality where the implant should be applied as well as mutual interaction, is presented. The results confirm necessity of bone tissue computational models creation on high resolution level including complex trabecular architecture. In this work the creation of trabecular structure computational model from data gained on micro-CT device is described. Further, the trabecular structure computational model was created on the 3D level with dental implant and the stress strain analysis was performed consequently. The last part of this work deals with introductory study of bone tissue modeling and remodeling.
|
|
|
Creating geometrical models of selected implants of hip joint
Kohoutek, Jan ; Vosynek, Petr (referee) ; Návrat, Tomáš (advisor)
According to the specification, the concept of the thesis is a research study, which is supposed to present global overview of the hip joint arthroplasty. It involves a short summary of basic methods used in biomechanical measurements of bone tissue and provides a comparison among isotropic homogeneous, isotropic inhomogeneous and orthotropic inhomogeneous material models and their impact on the results of the stress-strain analyses. In the thesis, there is also a short list of popular implants used in present times as well as a few examples of creating geometrical models of some prosthesis.
|
|
|
Assessment of the strength of the lumbar spine fixator screw using stochastically entered input variables
Rapantová, Zuzana ; Hrabec, Pavel (referee) ; Vosynek, Petr (advisor)
The bachelor's thesis deals with the strength and fatigue of the spinal rod fixator. The topic is addressed by creating a computational model with two lengths of fixation screws. Simulations are performed using the Ansys software with the application of Six Sigma analysis. The strength analysis is quantified from the average load values, and the stress-strain analysis employs stochastic input variables. The results demonstrate that the modulus of elasticity of the cancellous bone significantly affects the deformation of the fixator. In the conclusion, the output data between the two lengths undergo statistical tests. Based on the acceptance of hypotheses regarding the equality of mean values, it is evaluated that a screw not passing through the entire cross-section of the cancellous bone in the vertebra is more suitable.
|
|
|
Research study of mechanical properties of cranial tissue
Wojtek, Lukáš ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with the problematics of determining mechanical properties of cranial bone tissue. In this thesis a search study associated with an experimental determination of mechanical properties of bone tissues is executed. A brief history and progress of imaging methods and their importance of computation modelling are introduced. There are descriptions of histomorfometric parameters describing a structure of bone tissue at the micro level, ways of their computation and their impact on mechanical properties of bone tissue. Practical part of the thesis is focused on processing micro-CT images of cranial bone as well as analysing histomorfometric parameters (BV/TV, TbTh, TbSp) and subsequently stress strain analysis of selected sections of cranial bone tissue. Resulting Young´s modulus of elasticity of bone tissue [MPa] are compared with results from experiments from literature.
|
|
|
Biomechanical Study of Tooth Implants for Low Density Bone
Marcián, Petr ; Janíček, Přemysl (referee) ; Horyl, Petr (referee) ; Florian, Zdeněk (advisor)
This work deals with problem of dental implant area, where there are many problems at the dental implants application. The essential issue is the bone tissue quality at implant application, which sig-nificantly influences its deformation, tension and the possibility of subsequent implant failure. The knowledge of bone tissue mechanical properties of mandible and mandible with applied implant can significantly affect prediction of dental implant failure. The mechanical interaction can be described by variable determining deformation and tension of solved system. For this reason the computational modeling by using Finite Element Method was used for solving given problem. The computational model creation of solved system on the high resolution level is necessary for biomechanical assessment of implant failure, including bone tissue quality. For this purpose the biomechanical study was performed, which significantly spreads range of solved problem in this work afterwards. In this work the methodology, which describes assessment of bone tissue quality where the implant should be applied as well as mutual interaction, is presented. The results confirm necessity of bone tissue computational models creation on high resolution level including complex trabecular architecture. In this work the creation of trabecular structure computational model from data gained on micro-CT device is described. Further, the trabecular structure computational model was created on the 3D level with dental implant and the stress strain analysis was performed consequently. The last part of this work deals with introductory study of bone tissue modeling and remodeling.
|
|
|
Biomechanical Study of Human Mandible in Physiological State
Borák, Libor ; Horyl, Petr (referee) ; Bartáková, Sonia (referee) ; Janíček, Přemysl (referee) ; Florian, Zdeněk (advisor)
This study deals with the mechanical aspects of human mandible in physiological state during the occlusion. The work is focused on evaluation of stress-strain conditions of bone tissue. The emphasis is paid to the interaction of teeth with the bone. In addition, contact pres-sures in temporomandibular joints during various loading conditions were determined. The analysis of material model of some parts of the system regarding their modelling-level is pre-sented as well. The problem concerning the evaluation of stress-strain states is solved by computational simulation using the finite element method. The presented work is a detailed analysis of the parts of the masticatory system and a thorough description of their modelling is presented. Special focus is paid to modelling of cancellous bone as well as of periodontal tissue which mediates the interaction between a tooth and the alveolar bone. Three-dimensional geometry of the mandible and all its teeth has been obtained by using the digitizing of real objects, namely by using of three-dimensional optical scanner. Three various modelling levels of the material of periodontium are assessed: Linear iso-tropic model, bilinear isotropic model and linear orthotropic model. Characteristics of these models are analyzed and especially nine new constants describing orthotropic model (which is almost absent in the literature) are proposed. Two-dimensional models are used for analysis of differencies in mechanical response of cancellous bone to the tooth loading. Two cases are considered: Cancellous bone as a ho-mogenous continuous model on one hand and with detailed trabeculous architecture model on the other. Computational model is divided into four basic cases varying in level of masticatory appa-ratus geometry: A – 2D geometry of bone; B – 3D geometry of bone segment with one tooth through three teeth; C – 3D geometry of whole mandible with the only tooth; D – 3D geome-try of whole mandible with all teeth. All basic cases are further researched in different varia-tions for different material models etc.
|
|
|
The role of imaging techniques in creation of computational models in biomechanics.
Prášilová, Eva ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
The first part of the bachelor´s thesis is dealt with the processing history of imaging techniques and their indications in a clinical practice. From point of view of the computer modeling, the computer tomography plays an important role in biomechanics. The second part of this treatment describes the scan processing of sections of two human mandible obtained from computer CT and micro-CT tomography. As a non-invasive way procedure can be characterized the image processing techniques, which analyze a bone density and BVF. The manual segmentation was applied in this analysis provided in ROI analysis software. There are shown the graphs of the bone densities of segments of two human mandibles depending on the specimen length and also there are compared the results of the measurements received from the CT and micro-CT tomography. Then follow the results illustrating the correlation of the relations and recalculations, which can be used as the determination tool of the mechanical properties of bone tissue. Finally there are described the computer models created in ANSYS focused on the different bone density analysis and stress strain analysis.
|
guest ::
