|
|
Comparative analysis of physiological, degenerative and postoperative lumbar spine using computational modeling
Krejbychová, Adéla ; Návrat, Tomáš (referee) ; Vosynek, Petr (advisor)
This diploma thesis deals with the comparative analysis of the physiological, degenerative and postoperative state of the lumbar spine. The problem was solved by computational modeling using the finite element method. For this solution, it was necessary to create appropriate computational models. The spine physiological state was compared with cases of the lumbar spine with different levels of spondylolisthesis, cases of the lumbar spine with different sacral angles, and cases of lumbar spine with applied fixators. Based on the performed analyses, it was found that spine degenerative state has a great influence on the distribution of stress in the vertebral discs and the vertebra itself. Compared to the physiological state, with increasing level of the spondylolisthesis the stress in the vertebral discs increases, while the stress in the vertebral section decreases. Furthermore, the spondylolisthesis affects the force flow. The higher the level of the spondylolisthesis, the more the force flow is shifted onto the posterior articular ligaments. The best results in terms of the spine physiological state were achieved with the applied fixator model.
|
|
|
Stress-strain analysis of spinal segment with fixator
Mach, Ondřej ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This Master’s thesis deals with strain-stress analysis of a spine segment with an introduced fixator and a spine in natural physiological state. The work starts with a research study of literature sources that focus on similar issues. Furthermore, basic anatomy terminology and basic procedures for human spine stabilization were described. The formulated issue was resolved by computational modelling with the use of the finite element method. This solution requires a suitable computational model to be produced. This model consists of partial geometry, material, bond, and loading models. The geometric model was produced on the basis of CT scan images of a 60-year-old man which were used for producing five spine vertebrae T11–L3. Moreover, the geometric model consists of four intervertebral discs and eight articular cartilages. The material model includes homogeneous, heterogeneous and degraded properties of bone tissue. The strain-stress analysis was performed for seven loading states, which concern basic movements of human spine – standing, bending forward, bending backwards, bending left, bending right, left rotation and right rotation, with the use of ANSYS software. The assessed and analysed quantities include spine segment displacement, contact pressure of articular cartilages and stress on the fixator.
|
|
|
Biomechanical research study of skull plates and implants
Vystrk, Tomáš ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
Cranial implants along with fixators are used to restore the function of the damaged area of the human skull, where due to disease or injury the defect was created. When assessing the suitability of the implant and fixators the mechanical properties are significant. With this the material and shape of implant and fixators are related. The implant must be suitable with human bone tissue and also be able to withstand long-term loading. This paper summarizes the present knowledge regarding the design, manufacture and application of cranial implants. Next the stress-strain analysis of the loaded scull with irregular shaped defect, placed implant and fixation system is provided.
|
|
|
Stress - strain analysis of inferios limb with fixator type Poldi 7
Pásek, Jiří ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis deals with stress-strain analysis of inferious limb fixator type Poldi VII and tibia, whereupon is applied. In work is discribed creation of a geometry model of fixator and tibia, her discretization, loading and solving. Tibia was load by torsional moment and his magnitude was 10Nm. Then was perform a numerical solution in FEM system ANSYS Workbench 11.0. Further was effect biomechanical study about osification of broken part. Tibia was load by force, which evokes upright standing on both limbs.
|
|
|
Stress - strain analysis of inferios limb with fixator type Orthofix
Mrázek, Michal ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis aims to create a stress strain analysis of Orthofix external fixator applied to lower limb. The introduction summarizes the background research in available scientific publications, targetting the alternatives of treatment, namely application and fixation solutions of long bones. Furthermore parametric models of the fixator and tibia are created in CAD system CATIA. The fixator model enables to create different geometric variations simulating possible fixator settings and moment load in the range of 1-10 Nm. These geometric and loading states of fixator are solved via FEM in ANSYS. Single versions of the states of Orthofix fixator are then subjected to the stress strain analysis.
|
|
|
Analysis of the influence of the fixation setting of the fusion of the spinal vertebrae on the resulting correction of scoliosis
Kopecký, Tomáš ; Ščerba, Bořek (referee) ; Vosynek, Petr (advisor)
This bachelor's thesis deals with the numerical modeling of the spine with an established fixation device under three types of loading, with three types of connection between the last element of the fixator and its guiding rod. The thesis describes the creation of the spine and fixator models, as well as the setting of loading conditions. Three loading states are monitored, in both directions: flexion/extension, lateral bending in both directions, and axial rotation in both directions. Furthermore, the implementation of three types of connections for all these loadings is described. In the first case, the entire fixator is immovable, in the second case, the last element of the fixator can move along the axis of the spine, and in the last case, it can also rotate in all three directions. The evaluation and subsequent comparison of deformation in the direction of the spine axis are the outputs of this thesis. The final evaluation is that the displacement occurring is on the order of tenths of millimeters.
|
|
|
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.
|
|
|
Comparative analysis of physiological, degenerative and postoperative lumbar spine using computational modeling
Krejbychová, Adéla ; Návrat, Tomáš (referee) ; Vosynek, Petr (advisor)
This diploma thesis deals with the comparative analysis of the physiological, degenerative and postoperative state of the lumbar spine. The problem was solved by computational modeling using the finite element method. For this solution, it was necessary to create appropriate computational models. The spine physiological state was compared with cases of the lumbar spine with different levels of spondylolisthesis, cases of the lumbar spine with different sacral angles, and cases of lumbar spine with applied fixators. Based on the performed analyses, it was found that spine degenerative state has a great influence on the distribution of stress in the vertebral discs and the vertebra itself. Compared to the physiological state, with increasing level of the spondylolisthesis the stress in the vertebral discs increases, while the stress in the vertebral section decreases. Furthermore, the spondylolisthesis affects the force flow. The higher the level of the spondylolisthesis, the more the force flow is shifted onto the posterior articular ligaments. The best results in terms of the spine physiological state were achieved with the applied fixator model.
|
|
|
Stress-strain analysis of spinal segment with fixator
Mach, Ondřej ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This Master’s thesis deals with strain-stress analysis of a spine segment with an introduced fixator and a spine in natural physiological state. The work starts with a research study of literature sources that focus on similar issues. Furthermore, basic anatomy terminology and basic procedures for human spine stabilization were described. The formulated issue was resolved by computational modelling with the use of the finite element method. This solution requires a suitable computational model to be produced. This model consists of partial geometry, material, bond, and loading models. The geometric model was produced on the basis of CT scan images of a 60-year-old man which were used for producing five spine vertebrae T11–L3. Moreover, the geometric model consists of four intervertebral discs and eight articular cartilages. The material model includes homogeneous, heterogeneous and degraded properties of bone tissue. The strain-stress analysis was performed for seven loading states, which concern basic movements of human spine – standing, bending forward, bending backwards, bending left, bending right, left rotation and right rotation, with the use of ANSYS software. The assessed and analysed quantities include spine segment displacement, contact pressure of articular cartilages and stress on the fixator.
|
|
|
Stress - strain analysis of inferios limb with fixator type Poldi 7
Pásek, Jiří ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis deals with stress-strain analysis of inferious limb fixator type Poldi VII and tibia, whereupon is applied. In work is discribed creation of a geometry model of fixator and tibia, her discretization, loading and solving. Tibia was load by torsional moment and his magnitude was 10Nm. Then was perform a numerical solution in FEM system ANSYS Workbench 11.0. Further was effect biomechanical study about osification of broken part. Tibia was load by force, which evokes upright standing on both limbs.
|
guest ::
