scholarly journals A Novel Optimized Finite Element Model of Lenke 1 Adolescent Idiopathic Scoliosis Based on Dynamic Flexibility in Vivo

2021 ◽  
Author(s):  
Shengbo Niu ◽  
Jinyi Bai ◽  
Huan Yang ◽  
Dongsheng Zhang ◽  
Jianghong Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Adolescent Idiopathic Scoliosis ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Characteristic Curve ◽  
Element Model ◽  
Traction Load ◽  
The Finite Element Model

Abstract Bacground: It is of great significance to optimize the finite element model by spinal flexibility of adolescent idiopathic scoliosis (AIS) patients. The elastic modulus of the intervertebral disc is of critical importance in determining the overall flexibility of the spine. The aim of the present study was to optimize the finite element model of Lenke 1 AIS based on the dynamic flexibility in vivo by matching the optimal elastic modulus of the intervertebral disc.Methods: The Cobb angles under different longitudinal traction loads of one patient with Lenke 1 AIS were dynamically measured by using a spine morphometer with a posture sensor to plot the Cobb angle-longitudinal traction load characteristic curve. A 3D finite element model of the patient was established. The patient’s Cobb angle-longitudinal traction load characteristic curve was used as the dynamic flexibility in vivo to determine the optimal intervertebral disc elastic modulus of the model. Results: The dynamic flexibility curve in vivo of one Lenke 1 AIS patient was successfully obtained, and the patient’s optimal elastic modulus of the intervertebral disc for the finite element model was 5 MPa according to the dynamic flexibility curve in vivo.Conclusions: The use of dynamic flexibility in vivo to optimize the finite element model can provide a new perspective and approach for model optimization, which can reproduce the biomechanical characteristics in vivo of AIS patients.

scholarly journals Development of a Detailed Volumetric Finite Element Model of the Spine to Simulate Surgical Correction of Spinal Deformities

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mark Driscoll ◽  
Jean-Marc Mac-Thiong ◽  
Hubert Labelle ◽  
Stefan Parent
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Ex Vivo ◽  
Spinal Instrumentation ◽  
Element Model ◽  
Patient Data ◽  
Biomechanical Analysis ◽  
Published Data

A large spectrum of medical devices exists; it aims to correct deformities associated with spinal disorders. The development of a detailed volumetric finite element model of the osteoligamentous spine would serve as a valuable tool to assess, compare, and optimize spinal devices. Thus the purpose of the study was to develop and initiate validation of a detailed osteoligamentous finite element model of the spine with simulated correction from spinal instrumentation. A finite element of the spine from T1 to L5 was developed using properties and geometry from the published literature and patient data. Spinal instrumentation, consisting of segmental translation of a scoliotic spine, was emulated. Postoperative patient and relevant published data of intervertebral disc stress, screw/vertebra pullout forces, and spinal profiles was used to evaluate the models validity. Intervertebral disc and vertebral reaction stresses respected publishedin vivo,ex vivo, andin silicovalues. Screw/vertebra reaction forces agreed with accepted pullout threshold values. Cobb angle measurements of spinal deformity following simulated surgical instrumentation corroborated with patient data. This computational biomechanical analysis validated a detailed volumetric spine model. Future studies seek to exploit the model to explore the performance of corrective spinal devices.

The Vibration Analysis of Bone Conduction for Bone-Anchored Hearing Aids: In Vivo Human Temporal Bone

2011 ◽  
Vol 145 ◽  
pp. 93-98
Author(s):  
Jen Fang Yu ◽  
Zi Xiang Wei ◽  
Chin Kuo Chen ◽  
Ching I Chen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Temporal Bone ◽  
Hearing Aids ◽  
Bone Conduction ◽  
Element Model ◽  
Second Phase ◽  
Center Line ◽  
The Finite Element Model

This study constructed a 3D finite element model of temporal bone non-invasively, based on the computed tomography scan image of anin vivotemporal bone. To observe the geometry and measurements of the temporal bone, the finite element model was built using ANSYS®. The finite element model involved two phases. The first phase entailed discussing the natural vibration frequencies and vibration mode of the temporal bone. The second phase involved investigating the harmonic response. The base center and center line were established in the external auditory meatus and the 0 degree direction, respectively. The amplitude force was applied along the center line and at 15 degrees from center line and at distances of 30 mm, 35 mm, and 40 mm from the center point of ear canal. The amplitude of the bone-anchored hearing aids was approximately 550 g when stimulated by the vibrator. This paper discusses the frequency responses and characteristics of the BAHA vibrator on the mastoid of the temporal bone at the frequencies of 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 5 kHz, 6 kHz, 7 kHz, 8 kHz. Based on the results of conducting modal analysis of the temporal bone, 11 natural frequencies, 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1 k Hz, 2 kHz, 3 kHz, 4 kHz, 5 kHz, 6 kHz, and 7 kHz, included the stimuli frequencies of pure tone audiometry. Based on the results obtained by conducting harmonic analysis of the temporal bone, the performance of bone conduction at 35 mm and at 15 degrees was higher than those at 0 and -15 degrees.

Research on Spinal Lumbar Sacral Degeneration Finite Element Model

2018 ◽  
Vol 33 (02) ◽  
pp. 1954005
Author(s):  
Yu Hui ◽  
Kai-Rui Zhao ◽  
Jun-Sheng Wu ◽  
Bin Yu ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Element Model ◽  
Biomechanical Properties ◽  
Reconstruction Method ◽  
Element Analysis ◽  
Lumbar Segment ◽  
Disc Bulge ◽  
The Finite Element Model

Recent research has shown that lumbar disease has become common in China. Since the structure of the lumbar spine is extremely complex, a finite element analysis method was used to perform biomechanical simulation and analysis of stress and strain on the L3–L4 lumbar segment to provide both a scientific and theoretical basis for clinical diagnosis and medical research. The MC volume-rendering 3D reconstruction method was the first step to accurately constructing the finite element model of the L3–L4 lumbar sacral segment, which was simulated prior to the addition of the ligaments, fibrous ring, and other major spinal tissue. The finite element model network was classified and the material properties of the corresponding parts were described. According to the normal model, careful simulation and deformation were performed, in addition to intervertebral disc degeneration in various cases. We have provided a detailed and professional analysis of the biomechanical properties, providing a powerful biomechanical basis for the diagnosis of intervertebral disc bulge and degeneration.

On the Modeling of an Intervertebral Disc Using a Novel Large Deformation Multi-Shell Approach

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Sébastien Demers ◽  
Abdel-Hakim Bouzid ◽  
Sylvie Nadeau
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Large Deformation ◽  
Element Model ◽  
Anulus Fibrosus ◽  
The Difference ◽  
Model Realism ◽  
Contact Pressures ◽  
The Finite Element Model

The objective of this study is to develop an analytical model to predict the stresses and displacements in the lamellae of the intervertebral disc subjected to a compressive force. This is achieved by developing a model based on membrane theory combined to large deformation multishell structural behavior. Equations for longitudinal and circumferential stresses are formulated for each lamella of the anulus fibrosus. Multilamellae interaction is a statically indeterminate problem, which requires equations of compatibility of the displacements of adjacent lamellae to be resolved. The large deformation inherent to soft tissue is considered and the solution is obtained using an iterative process. Elastic interactions with a large deformation is a novelty in analytical modeling of soft tissues. This provides model realism and offers the possibility for new and in-depth investigations. Results are given for longitudinal and circumferential stresses and displacements as well as contact pressures for every lamella of the anulus fibrosus. The analytical results are compared to those of two finite element models. The results suggest that the most highly stressed zone is located on the innermost lamella. Stresses decrease through disc thickness and are at a maximum at the innermost lamella. Circumferential stress is predominant and the difference is less than 5% at any point of the anulus fibrosus when the analytical model is compared to the finite element model using coupled degrees of freedom at the lamellae interface. When compared to the finite element model using contact elements, the difference is below 11%. Contact pressures from the inside to the outside of the anulus fibrosus are shown to decrease nonlinearly. The model presented in this study has demonstrated that it is possible to analytically simulate the complex mechanical behavior of a multishell intervertebral disc subjected to compression, provided some simplifications. Further improvements are suggested to increase model realism and recommendations are given for future experimentation necessary to support both the analytical and numerical models.

Axial Compression Behavior of Masonry Prisms Considering the Influence of Mortar

2014 ◽  
Vol 884-885 ◽  
pp. 641-644
Author(s):  
Xiao Hong Zhou
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Model ◽  
Failure Mode ◽  
Compression Strength ◽  
Element Model ◽  
Compression Tests ◽  
Compression Behavior ◽  
Historic Masonry ◽  
The Finite Element Model

As one of most widely used structure, the behavior of masonry is influenced by its composition especially the mortar. In this paper, a series of compression tests was carried on masonry both with mortar (MP_m) and without mortar (MP_ds). Based on the results, the ultimate compression strength and elastic modulus has been compared firstly; after that, the failure mode of each prism was achieved, finally a finite element model was built for the numerical analysis on MP_ds. Results showed that compared with the MP_m, the elastic modulus of MP_ds has been reduced 30% which means the erosion of mortar should be considered when research on the historic masonry structures. The finite element model can simulate the compression strength and failure mode accurately, which showed great potential for the further parametric analysis.

Analysis of Packer Rubber Mechanics Properties

2014 ◽  
Vol 971-973 ◽  
pp. 380-389
Author(s):  
Jian Ning Wang ◽  
Gang Wu ◽  
Wei Yi Xie ◽  
Xin De Han ◽  
Ming Chao Gang
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Constitutive Model ◽  
Contact Stress ◽  
Theoretical Basis ◽  
Element Model ◽  
Rubber Material ◽  
Bottom Hole ◽  
Sealing Performance ◽  
The Finite Element Model

Abstract: The packer rubber stress in the bottom hole is more complex. Based on constitutive model of the packer rubber material, this paper determines such parameters as model constants, Poisson's ratio of rubber materials and elastic modulus by using experimental method, to build up the finite element model of center tube-rubber cylinder-casing for the purpose of stress analysis. Finally, the distribution regularity of rubber cylinder-casing contact stress and packer setting travel distance with varying loads is concluded. The results can provide the theoretical basis for further analysis of packer rubber sealing performance.

scholarly journals Sensitivity Analysis of the Influence of Structural Parameters on Dynamic Behaviour of Highly Redundant Cable-Stayed Bridges

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
B. Asgari ◽  
S. A. Osman ◽  
A. Adnan
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Structural Parameters ◽  
Element Model ◽  
Structural Behavior ◽  
Model Tuning ◽  
The Finite Element Model ◽  
Cable Stayed Bridges

The model tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics of cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however, the results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the analytical model of cable-stayed bridges. This paper presents a model updating algorithm for highly redundant cable-stayed bridges that can be used as an iterative manual procedure. The updating parameters are selected through the sensitivity analysis which helps to better understand the structural behavior of the bridge. The finite element model of Tatara Bridge is considered for the numerical studies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating the finite element model of cable-stayed bridges. The new aspects regarding effective material and structural parameters and model tuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges.

Biodynamics of Human Thorax With Body Armors Subject to Bullet Impact

2001 ◽  
Author(s):  
Y. W. Kwon ◽  
J. A. Lobuono
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Body Armor ◽  
Projectile Impact ◽  
Human Thorax ◽  
Trachea And Bronchi ◽  
Armor System ◽  
The Finite Element Model

Abstract The objective of this study is to develop a finite element model of the human thorax with a protective body armor system so that the model can adequately determine the thorax’s biodynamical response from a projectile impact. The finite element model of the human thorax consists of the thoracic skeleton, heart, lungs, major arteries, major veins, trachea, and bronchi. The finite element model of the human thorax is validated by comparing the model’s results to experimental data obtained from cadavers wearing a protective body armor system undergoing a projectile impact.

Dynamic Analysis of a Turbocharger Centrifugal Compressor Impeller

1991 ◽  
Author(s):  
V. Ramamurti ◽  
D. A. Subramani ◽  
K. Sridhara
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Centrifugal Compressor ◽  
Element Model ◽  
Simplified Model ◽  
Cyclic Symmetry ◽  
Compressor Impeller ◽  
Cyclic Symmetric ◽  
The Finite Element Model

Abstract Stress analysis and determination of eigen pairs of a typical turbocharger compressor impeller have been carried out using the concept of cyclic symmetry. A simplified model treating the blade and the hub as isolated elements has also been attempted. The limitations of the simplified model have been brought out. The results of the finite element model using the cyclic symmetric approach have been discussed.

Analysis of Effective Pre-Stress of Continuous Rigid Frame Bridge in Service Based on Inversion Theory

2013 ◽  
Vol 671-674 ◽  
pp. 1012-1015
Author(s):  
Zhao Ning Zhang ◽  
Ke Xing Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Inversion Method ◽  
Vertical Deflection ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Inversion Theory ◽  
Rigid Frame Bridge ◽  
The Finite Element Model

Due to the environment, climate, loads and other factors, the pre-stress applied to the beam is not a constant. It is important for engineers to track the state of the pre-stress in order to ensure security of the bridge in service. To solve the problem mentioned above, the paper puts forward a new way to analyze the effective pre-stress using the displacement inversion method based on the inversion theory according to the measured vertical deflection of the bridge in service at different time. The method is a feasible way to predict the effective pre-stress of the bridge in service. Lastly, taking the pre-stressed concrete continuous rigid frame bridge for example, the effective pre-stress is analyzed by establishing the finite element model.

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