scholarly journals Stress Analysis of Thoracolumbosacral Orthosis (TLSO) for Scoliosis deformity and its Effects on Gait Cycle

2019 ◽  
Vol 22 (3) ◽  
pp. 187-193
Author(s):  
Fahad Mohanad Kadhim ◽  
Sara I. Ahmed
Keyword(s):  
Gait Cycle ◽  
Center Of Mass ◽  
Maximum Pressure ◽  
Pressure Loading ◽  
Interface Pressure ◽  
Ansys Software ◽  
Thoracic Region ◽  
Maximum Value ◽  
Tissue Region ◽  
Scoliosis Deformity

This work involved two major parts: the first one is the experimental part which included treatment of scoliosis deformity by manufacturing thoracolumbosacral orthosis, measuring  the cobb angle of deformity, measuring the gait cycle data and walk path for both legs and suggesting a composite material to improve the mechanical properties of the orthosis and finally the interface pressure between trunk  and orthosis is measured for twelve points covering of the total TLSO surface area by using f-socket devise. The second part of this study is the numerical simulation part during which the stresses are calculated using Ansys software for calculating stresses due to interface pressure loading boundary condition. The result shows no deference in gait cycle phases but the clear difference noted in walking path due to deviate center of mass, maximum pressure recorded left thoracic region with 900KPa due to correct spinal deformity while the minimum pressure recorded at right chest with l40KPa because of it is tissue region and Maximum value of stress was recorded at the left thoracic region with 2.81MPa due to Maximum interface pressure at this point.

scholarly journals EFFECT OF ALUMINUM FOILS NUMBER AND ITS LENGTH IN IMPROVEMENT OF ELECTRIC FIELD DISTRIBUTION OF HIGH VOLTAGE CONDENSER BUSHING

2021 ◽  
Vol 25 (4) ◽  
pp. 67-83
Author(s):  
Zahraa G. Mustafa ◽  
◽  
Kassim R. Hameed ◽  
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
High Voltage ◽  
Ansys Software ◽  
Electrical Field ◽  
Stress Control ◽  
Electrical Stress ◽  
Maximum Value ◽  
Contour Plots ◽  
High Voltage System

High voltage condenser bushing is one of the important component that is widely used in the high voltage system. At high voltage levels more than 52kV the distribution of electric field in condenser bushing is irregular between the lead conductor and the grounded metallic flange. This paper studied the effects of changing in both: the number layers of aluminum foils and Oil impregnated Paper (OIP), increasing the length of aluminum foils layers, and also increasing the thickness of OIP layer on the distribution of electric potential and electric field in condenser bushing by using Finite Element Method (FEM) and built the bushing model in ANSYS software. The harmonic analysis was performed of the bushing model at maximum value of withstand voltage test at 50Hz, from the analysis results are obtained the maximum value of electric field on the inner and outer surface of the bushing, the obtained electric field values were good and acceptable compared to the permissible electrical stress values of the dielectric insulators. This work can also aid in the design of high voltage bushing stress control, a knowledge of the electrical field distribution in bushing geometry. Moreover the results of analysis are shown as contour plots, graphs plotted, and tables.

End Effect Attenuation in Tapered Roller Contacts

2009 ◽  
Author(s):  
Emanuel Diaconescu
Keyword(s):  
Pressure Distribution ◽  
Finite Length ◽  
Contact Length ◽  
Maximum Pressure ◽  
End Effect ◽  
End Effects ◽  
Maximum Value ◽  
Line Contacts ◽  
Tapered Roller

The end effect attenuation in finite length line contacts is mainly approached for cylindrical bodies. Multi-radius crowning may remove end effects in tapered roller contacts. Another method for leveling maximum pressure in these contacts is the use of polynomial generatrix. This paper investigates the effect of this generatrix in tapered roller contacts. An improved pressure distribution is obtained. This has a nearly flat maximum value along most of contact length.

Study of the Sensitivity of the Guanabara Bay PE-3 Pipeline to Geometric Imperfections

2004 ◽  
Author(s):  
Adilson Carvalho Benjamin ◽  
Joa˜o Nisan Correia Guerreiro ◽  
Rita de Ca´ssia Carvalho Silva ◽  
Abimael Fernando Dourado Loula
Keyword(s):  
Yield Strength ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Pipe Material ◽  
Guanabara Bay ◽  
Pressure Loading ◽  
Geometric Imperfections ◽  
Von Mises ◽  
Von Mises Stresses

This paper describes the study performed to investigate the sensitivity of the Guanabara Bay PE-3 pipeline to geometric imperfections. The main results of several FE analyses are presented. It is concluded that the PE-3 zigzag pipeline is geometrically stable when submitted to the maximum pressure loading and maximum temperature loading established in the design. Also it is shown that the von Mises stresses calculated in the analyses were below the yield strength of the pipe material.

Dynamic Analysis and Structure Optimization of Linear Vibration Screen

2013 ◽  
Vol 364 ◽  
pp. 42-45
Author(s):  
Yong Yan Wang ◽  
Xiao Liang Liu ◽  
Wen Bin Wei ◽  
Nan Qin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Analysis ◽  
Center Of Mass ◽  
Structure Optimization ◽  
Element Model ◽  
Linear Vibration ◽  
Ansys Software ◽  
Structural Modifications ◽  
The Finite Element Model

Simulation of simplified the part structures of vibration screen by ANSYS software, and then establishes the finite element model of the linear vibration screen. Modal analysis and harmonic analysis of finite element model, and then according to the analysis results corresponding local structural modifications and adjust the center of mass of the modified vibration screen. Last verified the rationality of structure optimization.

scholarly journals Similar sensorimotor transformations control balance during standing and walking

2021 ◽  
Vol 17 (6) ◽  
pp. e1008369
Author(s):  
Maarten Afschrift ◽  
Friedl De Groote ◽  
Ilse Jonkers
Keyword(s):  
Gait Cycle ◽  
Walking Speed ◽  
Balance Control ◽  
Center Of Mass ◽  
Linear Feedback ◽  
Sensorimotor Transformations ◽  
Robotic Devices ◽  
Walking Balance ◽  
Mass Position ◽  
Task Level

Standing and walking balance control in humans relies on the transformation of sensory information to motor commands that drive muscles. Here, we evaluated whether sensorimotor transformations underlying walking balance control can be described by task-level center of mass kinematics feedback similar to standing balance control. We found that delayed linear feedback of center of mass position and velocity, but not delayed linear feedback from ankle angles and angular velocities, can explain reactive ankle muscle activity and joint moments in response to perturbations of walking across protocols (discrete and continuous platform translations and discrete pelvis pushes). Feedback gains were modulated during the gait cycle and decreased with walking speed. Our results thus suggest that similar task-level variables, i.e. center of mass position and velocity, are controlled across standing and walking but that feedback gains are modulated during gait to accommodate changes in body configuration during the gait cycle and in stability with walking speed. These findings have important implications for modelling the neuromechanics of human balance control and for biomimetic control of wearable robotic devices. The feedback mechanisms we identified can be used to extend the current neuromechanical models that lack balance control mechanisms for the ankle joint. When using these models in the control of wearable robotic devices, we believe that this will facilitate shared control of balance between the user and the robotic device.

scholarly journals The effect of external lateral stabilization on the control of mediolateral stability in walking and running

2018 ◽  
Author(s):  
Mohammadreza Mahaki ◽  
Sjoerd M Bruijn ◽  
Jaap H. van Dieën
Keyword(s):  
Active Control ◽  
Repeated Measures ◽  
Gait Cycle ◽  
Center Of Mass ◽  
Step Width ◽  
Kinematic Data ◽  
Foot Placement ◽  
Consumption Data ◽  
Mediolateral Stability

It is still unclear how humans control mediolateral (ML) stability in walking and even more so for running. Here, foot placement adjustment as a main mechanism of active control of mediolateral stability was compared between walking and running. Moreover, to verify the role of foot placement as a means of active control of ML stability and associated metabolic costs in both modes of locomotion, this study investigated the effect of external lateral stabilization on foot placement control. Ten young adults participated in this study. Kinematic data of the trunk (T6) and feet (heels) as well as breath-by-breath oxygen consumption data were recorded during walking and running on a treadmill in normal and stabilized conditions. Coordination between ML trunk Center of Mass (CoM) state and subsequent ML foot placement, step width, and step width variability were assessed. Two-way repeated measures ANOVAs (either normal or SPM1d) were used to test for effects of walking vs. running and of normal vs. stabilized locomotion. We found a stronger association between ML trunk CoM state and foot placement in walking than in running from 90-100% of the gait cycle and also a higher step width variability in walking, but no significant differences in step width. The association between trunk CoM state and foot placement was significantly decreased by external lateral stabilization in walking and running, and this reduction was stronger in walking than in running from 75-100% of gait cycle. Surprisingly, energy cost significantly increased by external lateral stabilization, which was more pronounced in running than walking. We conclude that ML foot placement is coordinated to the CoM kinematic state to stabilize both walking and running. This coordination is more tight in walking than in running and appears not to contribute substantially to the energy costs of either mode of locomotion.

scholarly journals Analysis of Expansion Joint - A Case Study

2021 ◽  
Vol 9 (10) ◽  
pp. 45-51
Author(s):  
Prof. P R Subramaniam
Keyword(s):  
Variable Pressure ◽  
Pressure Loading ◽  
Ansys Software ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Pressure Load ◽  
Different Types ◽  
Comprehensive Modeling ◽  
Metallic Bellow

Abstract: Automotive, Aerospace, Pipeline industries widely use Bellows. Different types of bellows are used in these industries. The bellows are used for contraction or expansion applications. Repeated variable pressure loading and displacement on Metallic bellows joints results in bellows failure. This paper is a comprehensive modeling and analysis of an axial type exhaust metallic bellow due to varying pressure load and circumferential and radial displacement. All analysis completed using ANSYS software considering variable pressure load and cylindrical displacement as a boundary condition and perused the consequences. Stress distribution in the conditions of Case (i) variable pressure load and Case (ii) displacement are obtained. Keywords: ANSYS, FE Bellows, Finite Element Analysis, Bellow Failures

A case study on interface pressure pattern of two garment orthoses on a child with cerebral palsy

2020 ◽  
Vol 234 (8) ◽  
pp. 884-894
Author(s):  
Ida Hasni Shaari ◽  
Noor Azuan Abu Osman ◽  
Hanie Nadia Shasmin
Keyword(s):  
Cerebral Palsy ◽  
Maximum Pressure ◽  
Spastic Diplegia ◽  
Test Duration ◽  
Sitting Position ◽  
Interface Pressure ◽  
Truncal Ataxia ◽  
Sit To Stand ◽  
Different Levels

Many studies have shown that medical compression products produce different levels of interface pressure during the usage of the products. However, limited studies have explored the pattern of interface pressure exerted by orthotic garments. This case study aimed to investigate the pattern of interface pressure exerted by two types of orthotic garments on a child with cerebral palsy. A 13-year-old child diagnosed with ataxic spastic diplegia cerebral palsy has difficulty to perform sit-to-stand motion even with a walking frame due to his truncal ataxia. A TheraTogsTM orthosis and a Dynamic Lycra® Fabric Orthosis (DLFO) were prepared for the child. The child’s sit-to-stand ability without and with the usage of orthoses was recorded using five sit-to-stand tests. The garments’ interface pressure was measured using F-scan (9811E) and F-scan 6.5.1 version software. The pressure was recorded when the child was in sitting position and performing sit-to-stand-to-sit motion. Overall, the child completed the five sit-to-stand test duration within 2.53 ± 0.04 s and 2.51 ± 0.09 s with the usage of TheraTogsTM orthosis and DLFO, respectively. Higher pressure was exerted by Dynamic Lycra Fabric Orthosis (axillary = 122 mmHg) in contrast to TheraTogsTM orthosis (77 mmHg) when the child was in a sitting position. Lower pressure was exerted by DLFO (7 mmHg), over xiphoid level and for TheraTogsTM orthosis is 1.2 mmHg over axillary level when the child was performing sit-to-stand motion. The largest range of pressure was exerted by TheraTogsTM orthosis with a minimum pressure of 5 mmHg and a maximum pressure of 155 mmHg during sit-to-stand motion. Overall, the DLFO exerted higher mean interface pressure on the child in comparison to TheraTogsTM orthosis when the child’s body was in a sitting position wearing both upper garment and pants. Both TheraTogsTM orthosis and DLFO presented a different range of interface pressure over different body segments and activities.

Development of a Pressure Related Assessment Model of Seating Discomfort

1993 ◽  
Vol 37 (10) ◽  
pp. 831-835 ◽  
Author(s):  
Wenqi Shen ◽  
Ian A. R. Galer
Keyword(s):  
Factor Model ◽  
Pressure Ratio ◽  
Assessment Model ◽  
Maximum Pressure ◽  
Extensive Literature ◽  
Interface Pressure ◽  
Measuring Device ◽  
Seat Angle ◽  
Postural Changes ◽  
Seating Discomfort

This study consisted of the development of a factor model and a sitting interface pressure related assessment model of sitting discomfort, based on an extensive literature review. The factor model identified the force applied on the sitter's body as one of the main factors causing seating discomfort. The assessment model proposed that sitting discomfort mainly arises from feelings in the lumbar and buttock areas, and that local discomfort either depends upon or, is reflected by, the interface pressure. A pilot experiment was conducted to explore the utility of the assessment model by change of postural angles. Eleven subjects attended a 40 min sitting session. The independent variables were seat angle and seat-to-backrest angle. A pressure measuring device was used to record interface pressure between the subject and a prototype seat surface. A general comfort scale was administered after each pressure measurement. Results showed that all pressure measures were sensitive to postural changes of varied angulation, and that subjective ratings of comfort correlated with pressure measures, especially maximum pressure, average pressure ratio and maximum pressure gradient. Evidence from the pilot suggested that the model may have utility and eventually be used to assess seating discomfort.

Study of an aluminium mixing system based on permanent magnets

2020 ◽  
Vol 39 (1) ◽  
pp. 192-197
Author(s):  
Andrey Morev ◽  
Alexander Aliferov
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Rotation Velocity ◽  
Rotating Magnetic Field ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Angular Rotation ◽  
Content Type ◽  
Maximum Value ◽  
The Magnetic Field

Purpose The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath. Design/methodology/approach This model was developed in the ANSYS software package and is based on the application of the finite element method and finite volume. Findings The distribution of the velocity of the melt in a cylindrical vertical bath and the dependence of the maximum value of the melt displacement on the angular rotation velocity of the system of permanent magnets is obtained. Originality/value This work focusses on the interaction of the magnetic field of the moving magnets with the molten metal.

Sign in / Sign up

Export Citation Format

Share Document