Biomechanical study of cervical flexion myelopathy using a three-dimensional finite element method

2008 ◽  
Vol 8 (5) ◽  
pp. 436-441 ◽  
Author(s):  
Yoshihiko Kato ◽  
Hideo Kataoka ◽  
Kazuhiko Ichihara ◽  
Yasuaki Imajo ◽  
Takanori Kojima ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Spinal Cord ◽  
Finite Element ◽  
Gray Matter ◽  
Element Model ◽  
Biomechanical Study ◽  
Pia Mater ◽  
Static Compression ◽  
Cervical Flexion Myelopathy ◽  
Element Method

Object The goal of this study was to perform a biomechanical study of cervical flexion myelopathy (CFM) using a finite element method. Methods A 3D finite element model of the spinal cord was established consisting of gray matter, white matter, and pia mater. After the application of semi-static compression, the model underwent anterior flexion to simulate CFM. The flexion angles used were 5° and 10°, and stress distributions inside the spinal cord were then evaluated. Results Stresses on the spinal cord were very low under semi-static compression but increased after 5° of flexion was applied. Stresses were concentrated in the gray matter, especially the anterior and posterior horns. The stresses became much higher after application of 10° of flexion and were observed in the gray matter, posterior funiculus, and a portion of the lateral funiculus. Conclusions The 5° model was considered to represent the mild type of CFM. This type corresponds to the cases described in the original report by Hirayama and colleagues. The main symptom of this type of CFM is muscle atrophy and weakness caused by the lesion of the anterior horn. The 10° model was considered to represent a severe type of CFM and was associated with lesions in the posterior fand lateral funiculi. This type of CFM corresponds to the more recently reported clinical cases with combined long tract signs and sensory disturbance.

Biomechanical study of the effect of degree of static compression of the spinal cord in ossification of the posterior longitudinal ligament

2010 ◽  
Vol 12 (3) ◽  
pp. 301-305 ◽  
Author(s):  
Yoshihiko Kato ◽  
Tsukasa Kanchiku ◽  
Yasuaki Imajo ◽  
Kotaro Kimura ◽  
Kazuhiko Ichihara ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Stress Distribution ◽  
Gray Matter ◽  
High Stress ◽  
Posterior Longitudinal Ligament ◽  
Cord Compression ◽  
Biomechanical Study ◽  
Stress Distributions ◽  
Pia Mater ◽  
Static Compression

Object The authors evaluated the biomechanical effect of 3 different degrees of static compression in a model of the spinal cord in order to investigate the effect of cord compression in patients with ossification of the posterior longitudinal ligament (OPLL). Methods A 3D finite element spinal cord model consisting of gray matter, white matter, and pia mater was established. As a simulation of OPLL-induced compression, a rigid plate compressed the anterior surface of the cord. The degrees of compression were 10, 20, and 40% of the anteroposterior (AP) diameter of the cord. The cord was supported from behind by the rigid body along its the posterior border, simulating the lamina. Stress distributions inside of the cord were evaluated. Results The stresses on the cord were very low under 10% compression. At 20% compression, the stresses on the cord increased very slightly. At 40% compression, the stresses on the cord became much higher than with 20% compression, and high stress distributions were observed in gray matter and the lateral and posterior funiculus. The stresses on the compressed layers were much higher than those on the uncompressed layer. Conclusions The stress distributions at 10 and 20% compression of the AP diameter of the spinal cord were very low. The stress distribution at 40% compression was much higher. The authors conclude that a critical point may exist between 20 and 40% compression of the AP diameter of the cord such that when the degree of the compression exceeds this point, the stress distribution becomes much higher, and that this may contribute to myelopathy.

scholarly journals Finite Element Method modeling of Additive Manufactured Compressor Wheel

2021 ◽  
Author(s):  
Márton Tamás Birosz ◽  
Mátyás Andó ◽  
Sudhanraj Jeganmohan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Method Simulation ◽  
Element Model ◽  
Tensile Tests ◽  
Raw Material ◽  
Isotropic Hardening ◽  
Compressor Wheel ◽  
Material Extrusion ◽  
Element Method

AbstractDesigning components is a complex task, which depends on the component function, the raw material, and the production technology. In the case of rotating parts with higher RPM, the creep and orientation are essential material properties. The PLA components made with the material extrusion process are more resistant than VeroWhite (material jetting) and behave similarly to weakly cross-linked elastomers. Also, based on the tensile tests, Young’s modulus shows minimal anisotropy. Multilinear isotropic hardening and modified time hardening models are used to create the finite element model. Based on the measurements, the finite element method simulation was identified. The deformation in the compressor wheel during rotation became definable. It was concluded that the strain of the compressor wheel manufactured with material extrusion technology is not significant.

An inhomogeneous cell-based smoothed finite element method for the nonlinear transient response of functionally graded magneto-electro-elastic structures with damping factors

2018 ◽  
Vol 30 (3) ◽  
pp. 416-437 ◽  
Author(s):  
Liming Zhou ◽  
Ming Li ◽  
Bingkun Chen ◽  
Feng Li ◽  
Xiaolin Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Micro Electro Mechanical System ◽  
Functionally Graded ◽  
Elastic Structures ◽  
Mapping Procedure ◽  
Gaussian Integration ◽  
Smoothed Finite Element Method ◽  
Element Method

In this article, an inhomogeneous cell-based smoothed finite element method (ICS-FEM) was proposed to overcome the over-stiffness of finite element method in calculating transient responses of functionally graded magneto-electro-elastic structures. The ICS-FEM equations were derived by introducing gradient smoothing technique into the standard finite element model; a close-to-exact system stiffness was also obtained. In addition, ICS-FEM could be carried out with user-defined sub-routines in the business software now available conveniently. In ICS-FEM, the parameters at Gaussian integration point were adopted directly in the creation of shape functions; the computation process is simplified, for the mapping procedure in standard finite element method is not required; this also gives permission to utilize poor quality elements and few mesh distortions during large deformation. Combining with the improved Newmark scheme, several numerical examples were used to prove the accuracy, convergence, and efficiency of ICS-FEM. Results showed that ICS-FEM could provide solutions with higher accuracy and reliability than finite element method in analyzing models with Rayleigh damping. Such method is also applied to complex structures such as typical micro-electro-mechanical system–based functionally graded magneto-electro-elastic energy harvester. Hence, ICS-FEM can be a powerful tool for transient problems of functionally graded magneto-electro-elastic models with damping which is of great value in designing intelligence structures.

scholarly journals Analysis of Vertical Stiffness of Air Spring Based on Finite Element Method

2018 ◽  
Vol 153 ◽  
pp. 06006
Author(s):  
Jiatong Ye ◽  
Hua Huang ◽  
Chenchen He ◽  
Guangyuan Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Element Model ◽  
Simulation Method ◽  
Bench Test ◽  
Air Spring ◽  
Vertical Stiffness ◽  
Element Simulation ◽  
Element Method

In this paper, a finite element model of membrane air spring in the vehicle is established, and its vertical stiffness characteristics under a certain inflation pressure are analysed. The result of finite element simulation method is compared with the result of the air spring bench test. The accuracy and reliability of the finite element simulation method in nonlinear analysis of air spring system are verified. In addition, according to the finite element method, the influence of the installation of the air spring limit sleeve on its stiffness is verified.

scholarly journals COMPARISON OF SAW BLADE NATURAL FREQUENCIES AND CRITICAL SPEEDS USING CSAW AND FINITE ELEMENT ANALYSIS

2011 ◽  
Author(s):  
J. Poirier ◽  
P. Radziszewski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Element Model ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Saw Blade ◽  
Circular Saws ◽  
The Finite Element Model ◽  
Element Method

The natural frequencies of circular saws limit the operating speeds of the saws. Current industry methods of increasing natural frequency include pretensioning, where plastic deformation is induced into the saw. To better model the saw, the finite element model is compared to current software for steel saws; C-SAW, a software program that calculates frequencies for stiffened circular saws. Using C-SAW and the finite element method the results are compared and the finite element method is validated for steel saws.

Strength Analysis of the Seat Anchorages for Large Passenger Vehicles Using Finite Element Method

2013 ◽  
Vol 658 ◽  
pp. 340-344
Author(s):  
Somsak Siwadamrongpong ◽  
Supakit Rooppakhun ◽  
Natchaya Murachai ◽  
Pakorn Burakorn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Strength Analysis ◽  
Passenger Vehicle ◽  
Simulation Techniques ◽  
Vehicle Accident ◽  
Design For Safety ◽  
Vehicle Seat ◽  
Element Method

Since the vehicle accident is one of the major causes of dead and injury in Thailand, especially the large passenger vehicle. The seat anchorage was often damaged and lead to high number and critical of patient. To improve the safety of large passenger vehicle, seat anchorage should be investigated. The aim of this research was to analyze strength of seat anchorages for the bus according to European standard ECE Regulation 80 using finite element method and DOE(Design of Experimental) approach. In this study, the boundary conditions on finite element model of seat structure were defined according to the regulation. It is expected that the simulation techniques could be advantaged for seat anchorage analysis. This result will be used for further improvement of the bus seat anchorage design for safety and cost reduction in design processes.

Pipeline On-Bottom Stability Analysis Based on FEM Model

2011 ◽  
Author(s):  
Yong Bai ◽  
Zhimeng Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Procedure ◽  
Element Model ◽  
The Finite Element Method ◽  
Fem Model ◽  
Engineering Software ◽  
Calculation Results ◽  
Pipeline Design ◽  
Element Method

Pipeline on-bottom stability is one of the sophisticated problems in subsea pipeline design procedure. Due to the uncertainty of the pipe-soil interaction and environment loads, including wave, current, or earthquake, etc., it is classified as the typical nonlinear problem. The Finite Element Method is introduced into pipeline engineering several years ago. More and more special engineering software such as AGA, PONDUS are available in market. However, when doing a project, some abnormal data was found when compared the DnV calculation results and AGA. In order to know the behavior of pipeline on seabed under wave and current load, finite element method – ABAQUS is introduced to do this analysis. The ABAQUS/explicit is used to simulate 600s pipeline dynamic response. The pipeline is supposed to be exposed on seabed and the selected seabed model is large enough to avoid the edge effect. ABAQUS calculation results are compared with the requirements in DnV rules to verify the validity of finite element model.

Modeling and Simulation of High Speed Intermittent Cutting Based on the Finite Element Method

2013 ◽  
Vol 683 ◽  
pp. 556-559
Author(s):  
Bin Bin Jiao ◽  
Fu Sheng Yu ◽  
Yun Jiang Li ◽  
Rong Lu Zhang ◽  
Gui Lin Du ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Field ◽  
Cutting Force ◽  
High Speed ◽  
Element Model ◽  
Periodic Variation ◽  
Element Analysis ◽  
Intermittent Cutting ◽  
Element Method

In order to study the distribution of the stress field in the high-speed intermittent cutting process, finite element model of high-speed intermittent cutting is established. Exponential material model of the constitutive equation and adaptive grid technology are applied in the finite element analysis software AdvantEdge. The material processing is simulated under certain cutting conditions with FEM ( Finite Element Method ) and the distribution of cutting force, stress field, and temperature field are received. A periodic variation to the cutting force and temperature is showed in the simulation of high-speed intermittent cutting. Highest value of the milling temperature appears in front contacting area of the knife -the chip.and maximum stress occurs at the tip of tool or the vicinity of the main cutting edge. The analysis of stress and strain fields in-depth is of great significance to improve tool design and durability of tool.

Finite Element Modeling of Electromagnetic Crimping of Cu-SS Tube-to-Tube Joint Along With Simulation of Destructive Testing for Strength Prediction of the Joint

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Deepak Kumar ◽  
Sachin D. Kore ◽  
Arup Nandy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Compressive Strength ◽  
Element Model ◽  
Strength Prediction ◽  
Force Distribution ◽  
Radial Deformation ◽  
Destructive Testing ◽  
Pull Out ◽  
Element Method

Abstract This work explores the tube-to-tube joining of copper (outer) and stainless steel (inner) using electromagnetic crimping. Stand-off distance is kept constant during all the experiments. ls-dynaTM electromagnetic module, which utilizes finite element method combined with the boundary element method, is used to perform numerical simulations and the model is validated with experimentally observed thinning and radial deformation of the outer tube during electromagnetic crimping. Effect of slit of the field shaper on Lorentz force distribution is studied. It is observed that the slit of the field shaper leads to uneven radial deformation. Furthermore, a novel finite element model has been developed to predict the pull-out and compressive strength of the joint. Results are validated with the experimentally observed data.

scholarly journals Study on the Effect of Different Delamination Defects on Buckling Behavior of Spar Cap in Wind Turbine Blade

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jianwei Li ◽  
Jinghua Wang ◽  
Leian Zhang ◽  
Xuemei Huang ◽  
Yongfeng Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Reference Value ◽  
Element Model ◽  
Theory And Practice ◽  
The Finite Element Method ◽  
Buckling Behavior ◽  
Element Method

Delamination is detrimental to the composite materials, and it may occur in the manufacturing process of the unidirectional laminate of the spar cap in wind turbine blades. This paper studies the effect of different delamination defects on the strength of the unidirectional laminate. The finite element model of laminate with different delamination areas and delamination heights is established using solid elements. The eigenvalues of laminates have different parameters calculated based on the finite element method. The final coupon test is used to verify the conclusions of simulation results. The finite element method presented in this study shows excellent capabilities to predict the buckling behavior of the laminate. The buckling eigenvalue of tested laminate is negatively correlated with the delamination area and positively correlated with the delamination height under the edgewise load. The S11, which is too high at the boundary of the delamination region, plays a significant role in buckling failure. It has a particular reference value for testing the laminate of blade both in theory and practice.

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