scholarly journals In Silico of Different Gait Cycle in Customised Leg Orthosis: A Finite Element Approach

2021 ◽  
Vol 16 ◽  
pp. 1-8
Author(s):  
Ahmad Amirul Faiz Mamat Hazri ◽  
Amir Mustakim Ab Rashid ◽  
Abdul Halim Abdullah ◽  
Ng Bing Wui ◽  
Ahmad Kafrawi Nasution ◽  
...  

Leg orthosis is one of medical device for fracture bone treatment. Several complications have been reported when patients are wearing the conventional Plaster of Paris or fibreglass leg orthosis. Its including numbness due to tight application, swelling, venous congestion and skin irritation. Therefore, the aim of this study is to develop and biomechanical analyse a customized leg cast that could tackle those complications. First, the leg was scanned using a 3D scanner. The leg cast was constructed from a 3D scanned leg model and designed using 3-Matic software which later simulated in finite element analysis using Marc software. The study focuses on three gait cycles; midstance, heel strike and toe off where stress and deformation were predicted. From the results, the cast only supported the ankle in midstance phase with only 7.297MPa stress and not capable to support the ankle in heel strike and toe off phases with maximum stress of 106.99 MPa and 213.12 MPa, respectively, which are beyond its yield strength of ABS, 23MPa. The average of overall displacement occurred for both skin and cast were less than 1.5mm. In short, the cast could only support the ankle in midstance phase and cannot be used for heel strike.

2021 ◽  
Vol 10 (17) ◽  
pp. 3986
Author(s):  
Chia-Hsuan Lee ◽  
Arvind Mukundan ◽  
Szu-Chien Chang ◽  
Yin-Lai Wang ◽  
Shu-Hao Lu ◽  
...  

Finite element analysis (FEA) has always been an important tool in studying the influences of stress and deformation due to various loads on implants to the surrounding jaws. This study assessed the influence of two different types of dental implant model on stress dissipation in adjoining jaws and on the implant itself by utilizing FEA. This analysis aimed to examine the effects of increasing the number of fences along the implant and to compare the resulting stress distribution and deformation with surrounding bones. When a vertical force of 100 N was applied, the largest displacements found in the three-fenced and single-fenced models were 1.7469 and 2.5267, respectively, showing a drop of 30.8623%. The maximum stress found in the three-fenced and one-fenced models was 13.518 and 22.365 MPa, respectively, showing a drop of 39.557%. Moreover, when an oblique force at 35° was applied, a significant increase in deformation and stress was observed. However, the three-fenced model still had less stress and deformation compared with the single-fenced model. The FEA results suggested that as the number of fences increases, the stress dissipation increases, whereas deformation decreases considerably.


2012 ◽  
Vol 479-481 ◽  
pp. 2046-2049
Author(s):  
Xi Ping Guo ◽  
Yan Fei Feng

Stress and deformation analysis of 950 mill housing was done by means of ANSYS to calculate the maximum stress and deformation. Strength and stiffness of the mill roll were checked to meet requirements. The weakness was revealed of the structure for the mill housing, and it is significant for similar mill housing designs.


2016 ◽  
Vol 835 ◽  
pp. 632-638
Author(s):  
Zhi Hong Wang ◽  
Jin Biao Wu ◽  
Jia Wu Liu

A high clearance self-propelled sprayer was designed, and a 3D model of sprayer frame was built with CATIA. Its finite element model was built by using Hypermesh, and it was imported to ABAQUS for finite element analysis. The analysis researched the stress and deformation of frame under four typical conditions of constant-velocity, torsion, emergency braking and emergency turning. The weak region of strength in the variable track mechanism was found, and a size optimization research was carried to the square pipe of the variable track mechanism. The result showed that the maximum stress of frame after optimization decreased obviously, and the distribution of stress became much more reasonable. The optimization ensured the reliability of the frame design.


Author(s):  
Yuqiao Zheng ◽  
Fugang Dong ◽  
Huquan Guo ◽  
Bingxi Lu ◽  
Zhengwen He

The study obtains a methodology for the bionic design of the tower for wind turbines. To verify the rationality of the biological selection, the Analytic Hierarchy Procedure (AHP) is applied to calculate the similarity between the bamboo and the tower. Creatively, a bionic bamboo tower (BBT) is presented, which is equipped with four reinforcement ribs and five flanges. Further, finite element analysis is employed to comparatively investigate the performance of the BBT and the original tower (OT) in the static and dynamic. Through the investigation, it is suggested that the maximum deformation and maximum stress can be reduced by 5.93 and 13.75% of the BBT. Moreover, this approach results in 3% and 1.1% increase respectively in the First two natural frequencies and overall stability.


2021 ◽  
Vol 11 (2) ◽  
pp. 858
Author(s):  
Mara Terzini ◽  
Andrea Di Pietro ◽  
Alessandro Aprato ◽  
Stefano Artiaco ◽  
Alessandro Massè ◽  
...  

Acetabular fractures have a high impact on patient’s quality of life, and because acetabular fractures are high energy injuries, they often co-occur with other pathologies such as damage to cartilage that could increase related morbidity; thus, it appears of primary importance developing reliable treatments for this disease. This work aims at the evaluation of the biomechanical performances of non-conservative treatments of acetabular fractures through a finite element approach. Two pelvic plates models (the standard suprapectineal plate—SPP, and a suprapectineal quadrilateral surface buttressing plate—SQBP) were analyzed when implanted on transverse or T-shaped fractures. The plates geometries were adapted to the specific hemipelvis, mimicking the bending action that the surgeon performs on the plate intraoperatively. Implemented models were tested in a single leg stance condition. The obtained results show that using the SQBP plate in transverse and T-shaped acetabular fractures generates lower bone stress if compared to the SPP plate. Interfragmentary movement analysis shows that the SQBP plate guarantees greater stability in transverse fractures. In conclusion, the SQBP plate seems worthy of further clinical analysis, having resulted as a promising option in the treatment of transverse and T-shaped acetabular fractures, able to reduce bone stress values and to get performances comparable, and in some cases superior, to traditional fixation.


1983 ◽  
Vol 105 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Hua-Ping Li ◽  
F. Ellyin

A plate weakened by an oblique penetration of a circular cylindrical hole has been investigated. The stress concentration around the hole is determined by a finite-element method. The results are compared with experimental data and other analytical works. Parametric studies of effects of angle of inclination, plate thickness, and width are performed. The maximum stress concentration factor (SCF) obtained from the finite-element analysis is higher than experimental results, and this deviation increases with the increase of angle of skewness. The major reason for this difference is attributed to the shear-action between layers parallel to the plate surface which cannot be directly included in the two-dimensional elements. An empirical formula is derived which accounts for the shear-action and renders the finite-element predictions in line with experimentally observed data.


1980 ◽  
Vol 102 (4) ◽  
pp. 430-432 ◽  
Author(s):  
R. D. Blevins

The elastic thermal stresses in a welded transition between two pipes of the same size but different alloys are explored. A stress-free temperature is postulated and the stress due to a uniform change in temperature is characterized by the maximum stress intensity in the weld. A simple expression for predicting this maximum stress intensity is developed based on the results of finite element analysis.


Author(s):  
Nikhil Joshi ◽  
Pritha Ghosh ◽  
Jonathan Brewer ◽  
Lawrence Matta

Abstract API RP 1102 provides a method to calculate stresses in buried pipelines due to surface loads resulting from the encroachment of roads and railroads. The API RP 1102 approach is commonly used in the industry, and widely available software allows for quick and easy implementation. However, the approach has several limitations on when it can be used, one of which is that it is limited to pipelines crossing as near to 90° (perpendicular crossing) as practicable. In no case can the crossing be less than 30° . In this paper, the stresses in the buried pipeline under standard highway vehicular loading calculated using the API RP 1102 method are compared with the results of two other methods; an analytical method that accounts for longitudinal and circumferential through wall bending effects, and the finite element method. The benefit of the alternate analytical method is that it is not subject to the limitations of API RP 1102 on crossing alignment or depth. However, this method is still subject to the limitation that the pipeline is straight and at a uniform depth. The fact that it is analytical in nature allows for rapid assessment of a number of pipes and load configurations. The finite element analysis using a 3D soil box approach offers the greatest flexibility in that pipes with bends or appurtenances can be assessed. However, this approach is time consuming and difficult to apply to multiple loading scenarios. Pipeline crossings between 0° (parallel) and 90° (perpendicular) are evaluated in the assessment reported here, even though these are beyond the scope of API RP 1102. A comparison across the three methods will provide a means to evaluate the level of conservatism, if any, in the API RP 1102 calculation for crossing between 30° and 90° . It also provides a rationale to evaluate whether the API RP 1102 calculation can potentially be extended for 0° (parallel) crossings.


2020 ◽  
Vol 62 (4) ◽  
pp. 357-364
Author(s):  
Yusuf Aytaç Onur ◽  
Hakan Gelen

Abstract In this study, the stress on portal crane components at various payloads has been investigated theoretically, numerically and experimentally. The portal crane was computer-aided modeled and finite element analyses were performed so that the most stressed points at the each trolley position investigated on the main girder could be determined. In addition, the critical points were marked on the portal crane, and strain gages were attached to the those critical points so that stress values could be experimentally determined. The safety factor values at different payloads were determined by using finite element simulation. Results indicate that the most stressed component in the examined portal crane is the main girder. Experimental results indicate that the maximum stress value on the main girder is 3.05 times greater than the support legs and 8.99 times larger than the rail.


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