scholarly journals Biomechanical Effects of Position-Loading During Cervical Rotatory Manipulation: A Finite Element Analysis

2020 ◽  
Author(s):  
Huihao Wang ◽  
Hongsheng Zhan ◽  
Kuan Wang ◽  
Zhen Deng ◽  
Xiaofei Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Neck Pain ◽  
Contact Pressure ◽  
Articular Surface ◽  
Angular Displacement ◽  
Element Model ◽  
Intervertebral Discs ◽  
Element Analysis ◽  
Articular Surfaces ◽  
The Right

Abstract Background: Cervical rotatory manipulation(CRM) is one of the most common treatments for neck pain in China. This study utilized a finite element method (FEM) to model the biomechanical effects of positioning during CRM in a normal sitting position. Methods: Passive head kinematics data, including angular displacement in six directions, were recorded. These data were then imported and a finite element model constructed, then validated. Relative angular displacements, and stress on the intervertebral discs and articular surfaces were calculated in a standard symmetry model (SSM) and compared with a pathological model (PM).Results: The results indicate that the intervertebral disc pressure (IDP) at the C2-C3, C3-C4 and C4-C5 discs subjected to CRM with position-loading were lower than the pressures experienced without position-loading. Furthermore, IDP on the target C5-C6 segment during CRM with position-loading in the PM was lower than that without position-loading, the former being close to the IDP of the C5-C6 segment during CRM without position-loading in the SSM. The left articular surface contact pressure of the target C5-C6 segment subjected to CRM towards the right without position-loading in the PM was slightly lower than that of the right articular surface experiencing leftward manipulation and lower than that predicted by the SSM. However, contact pressure of the C5-T1 segment in leftward CRM with position-loading in the PM and C6-T1 in rightward CRM with position-loading in the PM were significantly higher than the standard threshold, especially for contact pressure on the articular surfaces of C5-C6 in leftward CRM with position-loading in the PM. Conclusions: CRM should be considered a promising strategy to mitigate neck pain in patients.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

scholarly journals A finite element analysis of sacroiliac joint displacements and ligament strains in response to three manipulations

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Sacroiliac Joint ◽  
Clinical Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ligament Strain ◽  
Dimensional Finite Element ◽  
The Right ◽  
Three Dimensional Finite Element

Abstract Background Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments. Methods A three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations. Results MOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments. Conclusion The three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.

Combined Effects of Tube Projection, Initial Tube-Tubesheet Clearance, and Tube Material Strain Hardening on Rolled Joint Strength

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
N. Merah ◽  
A. Al-Aboodi ◽  
A. N. Shuaib ◽  
Y. Al-Nassar ◽  
S. S. Al-Anizi
Keyword(s):  
Finite Element ◽  
Strain Hardening ◽  
Contact Pressure ◽  
Joint Strength ◽  
Element Model ◽  
Design Parameters ◽  
Radial Clearance ◽  
Tube Material ◽  
Element Analysis ◽  
Interfacial Pressure

The tube-to-tubesheet joint strength is measured in terms of interfacial pressure between the tube’s outer surface and tubesheet bore. The strength of a rolled joint is influenced by several design parameters, including the type of tube and tubesheet materials, initial tube projection, and the initial radial clearance between the tube and tubesheet, among other factors. This paper uses finite element analysis (FEA) to evaluate the effect of several parameters on the strength of rolled joints having large overtolerances, a situation that applies to used equipment. An axisymmetric finite element model based on the sleeve diameter and rigid tube expanding roller concepts was used to analyze the effects of tube projection, initial tube-tubesheet clearance, and tube material strain-hardening property on the deformation behavior of the rolled tube and on the strength of the tube-tubesheet joint. The FEA results show that for zero tube projection (flush) the initial clearance effect is dependent on the strain-hardening capability of the tube material. For low strain-hardening tube material the interfacial pressure remains constant well above the Tubular Exchanger Manufacturer’s Association maximum overtolerance. A drastic reduction in joint strength is observed at high values of radial clearances. The cut-off clearance (clearance at which the interfacial pressure starts to drop) is found to vary linearly with the tube material hardening level, and the contact stress increases slightly for moderate strain-hardening tube materials but shows lower cut-off clearance levels. Furthermore, with flush tubes the maximum contact pressure occurs close to the secondary face (at the end of rolling) while for joints with initial tube projection the contact pressure shows two maxima occurring near the primary and the secondary faces. This is attributed to the presence of two elbows in tube deformation near the primary and secondary faces. The average interfacial pressure increased with increasing projection length for all clearances. Tube material strain hardening enhances the interfacial pressure in a similar fashion for all initial tube projection lengths considered in the analysis.

Finite Element Analysis of Cold Bend Pipes Under Bending Loads

2010 ◽  
Author(s):  
Millan Sen ◽  
Roger Cheng
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Vertical Direction ◽  
Element Model ◽  
Element Analysis ◽  
Cold Bending ◽  
Bending Process ◽  
Cold Bends ◽  
Full Scale Tests ◽  
The Right

Cold bends are required in pipelines at locations of changes in horizontal or vertical direction in the right of way. Due to this change of direction, pipeline deformations caused by geotechnical or operational loading conditions tend to accumulate at the site of cold bends. These deformations may become sufficient to cause local buckling at the bend. For pipeline design, it is important to understand the level of deformation that a cold bend can accumulate prior to local buckling so that the strain capacity can be compared to the expected pipeline deformations. Evaluating the buckling strain of cold bends is extremely complex due to the residual stresses, ripples, and material transformations cause by the cold bending process. Accordingly a finite element model was developed herein. This model accounted for the cold bend geometry, initial imperfections, and the material transformations caused by the cold bending process. This model was validated against 7 full scale tests of cold bend pipes that were subjected to bend loading and internal pressure. The global and local behavior of this model exhibited reasonable correlation against the tests.

THE EFFECT OF ARTICULAR SURFACE SHAPE AND TENDON FORCES OF TOTAL WRIST ARTHROPLASTY SYSTEMS: A FINITE ELEMENT STUDY

2012 ◽  
Vol 15 (04) ◽  
pp. 1250021 ◽  
Author(s):  
Matthew B. A. McCullough ◽  
Brian D. Adams ◽  
Nicole M. Grosland
Keyword(s):  
Finite Element ◽  
Articular Surface ◽  
Surface Shape ◽  
Element Analysis ◽  
Future Directions ◽  
Ulnar Deviation ◽  
Articular Surfaces ◽  
Total Wrist Arthroplasty ◽  
Flexion Extension ◽  
Wrist Arthroplasty

In order to better understand the behavior of the total wrist implant systems, finite element analysis (FEA) was used to model the articular surfaces of two unconstrained total wrist arthroplasty (TWA) devices. After creating models based on manufacturer specifications, simulations of flexion, extension, radial deviation, ulnar deviation and circumduction were run with simulated moments from surrounding tendons under displacement control. In addition, simulations were run under positioning that represented a pronated and supinated forearm as well as unstable conditions. Understanding implant behavior and capabilities as related to the shape of the articular surfaces is important for proper prescription of implants as well as determining future directions for the design of arthroplasty devices.

Finite Element Analysis of Fixation System Influence on the Thoracolumbar Spine Stability

2016 ◽  
Vol 821 ◽  
pp. 685-692 ◽  
Author(s):  
Klaudia Szkoda ◽  
Celina Pezowicz
Keyword(s):  
Finite Element ◽  
Sagittal Plane ◽  
Thoracolumbar Spine ◽  
Element Model ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Transpedicular Fixation ◽  
The Stability

All segments of the spine are characterized by a corresponding curvature in the sagittal plane and different geometrical parameters of vertebrae, which affects the complicated structure of transition between subsequent segments. The aim of the study was to assess changes occurring in the thoracolumbar spine, as a result of application of the transpedicular fixation. The research was conducted on finite element model, which was constructed on the basis of CT images. Five different configurations of the model were analyzed: focusing on vertebral compression fractures and degeneration of intervertebral discs. The analysis showed that the highest displacement occurred for a segment with intervertebral disc degeneration. Transpedicular fixation of injured thoracolumbar spine is given the opportunity to improve the stability and stiffness of the segment under consideration.

scholarly journals A Finite Element Analysis of Sacroiliac Joint Displacements and Ligament Strains in Response to Three Manipulations

2020 ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Sacroiliac Joint ◽  
Clinical Effect ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ligament Strain ◽  
Dimensional Finite Element ◽  
The Right ◽  
Three Dimensional Finite Element

Abstract BackgroundClinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the SIJ and the strains of the surrounding ligaments.MethodsA three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations.ResultsMOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments.ConclusionThe three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP may be the most effective of these manual therapies.

scholarly journals A Finite Element Analysis of Sacroiliac Joint Displacements and Ligament Strains in Response to Three Manipulations

2020 ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Sacroiliac Joint ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ligament Strain ◽  
Dimensional Finite Element ◽  
The Right ◽  
Three Dimensional Finite Element

Abstract Background: Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the pressures and displacements of SIJ, and the strains of the surrounding ligaments. Methods: A three-dimensional finite element model of the pelvis-femur was developed. The manipulation of hip and knee flexion (MHKF), the manipulation of oblique pulling (MOP), and the manipulation of lower limb hyperextension (MLLH) were simulated. The pressures and displacements of SIJs, and the strains of the surrounding ligaments were analyzed under the three manipulations. Results: The MOP produced the greatest pressure on the left SIJ, at 6.6 MPa, while the MHKF could produce the lowest pressure on the right SIJ, at 1.5 MPa. The displacements of SIJs were all less than 1mm in the three manipulations. The three manipulations could cause different degrees of the strains of ligaments around the SIJs, and the MOP could produce the largest strain of ligaments. Conclusion: The three manipulations all produced small displacements of SIJs, while they caused different degrees of ligament strains, which might be the reason for relieving the SIJ pain. The MOP may be a more effective manual therapy. Key words: Manipulation, Sacroiliac joint, Displacement, Ligament strain, Finite element analysis.

scholarly journals The Effects of Physiological Biomechanical Loading on Intradiscal Pressure and Annulus Stress in Lumbar Spine: A Finite Element Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Siti Nurfaezah Zahari ◽  
Mohd Juzaila Abd Latif ◽  
Nor Raihanah Abdull Rahim ◽  
Mohammed Rafiq Abdul Kadir ◽  
Tunku Kamarul
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Three Dimensional ◽  
Element Model ◽  
Intervertebral Discs ◽  
Intradiscal Pressure ◽  
Element Analysis ◽  
Physiological Loading ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The present study was conducted to examine the effects of body weight on intradiscal pressure (IDP) and annulus stress of intervertebral discs at lumbar spine. Three-dimensional finite element model of osseoligamentous lumbar spine was developed subjected to follower load of 500 N, 800 N, and 1200 N which represent the loads for individuals who are normal and overweight with the pure moments at 7.5 Nm in flexion and extension motions. It was observed that the maximum IDP was 1.26 MPa at L1-L2 vertebral segment. However, the highest increment of IDP was found at L4-L5 segment where the IDP was increased to 30% in flexion and it was more severe at extension motion reaching to 80%. Furthermore, the maximum annulus stress also occurred at the L1-L2 segment with 3.9 MPa in extension motion. However, the highest increment was also found at L4-L5 where the annulus stress increased to 17% in extension motion. Based on these results, the increase of physiological loading could be an important factor to the increment of intradiscal pressure and annulus fibrosis stress at all intervertebral discs at the lumbar spine which may lead to early intervertebral disc damage.

Finite Element Analysis on the Influence of Back-Up Ring on the Sealing Effect of Rubber O-Ring

2011 ◽  
Vol 199-200 ◽  
pp. 1595-1599
Author(s):  
Dian Xin Li ◽  
Hong Lin Zhao ◽  
Shi Min Zhang ◽  
Chang Run Wu ◽  
Xian Long Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Service Life ◽  
Contact Pressure ◽  
Von Mises Stress ◽  
Analysis Software ◽  
Element Analysis ◽  
Von Mises ◽  
The Right

Based on finite element analysis software ANSYS, the deformation and force condition of the rubber sealing o-ring pre and post with back-up ring under different oil pressure conditions was analyzed. The von mises stress distribution of the o-ring and the change of contact pressure between o-ring and sealing interface pre and post with back-up ring under different oil pressure conditions were discussed. The results show that, the maximum von mises stress of the o-ring is smaller and the maximum von mises stress of the sealing system concentrates on the left top and the right bottom of the back-up ring after using it; the o-ring will not be extruded into the gap of the groove because of the existence of back-up ring which prevents gap-bite and prolongs service life of the o-ring; the contact pressure between o-ring and sealing interface increased, thus the sealing reliability of the system increased.

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