scholarly journals Finite Element Analysis of a Novel Approach for Knee and Ankle Protection during Landing

2021 ◽  
Vol 11 (4) ◽  
pp. 1912
Author(s):  
Xueqing Wu ◽  
Baoqing Pei ◽  
Wei Wang ◽  
Da Lu ◽  
Lei Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Articular Surface ◽  
Lower Extremities ◽  
Peak Stress ◽  
Biomechanical Analysis ◽  
Element Analysis ◽  
Novel Approach ◽  
Articular Cartilages ◽  
Serious Injury ◽  
The Impact

There is a high risk of serious injury to the lower extremities during a human drop landing. Prophylactic knee and ankle braces are commonly used to reduce injury by restraining the motion of joints. However, braces that restrain joint range of motion (ROM) may have detrimental effects on the user’s kinematical performance and joint function. The present study aimed to propose a novel set of double-joint braces and to evaluate its protective performance in terms of the ankle and knee. Accordingly, the finite element method was performed to investigate the biomechanical responses of the ankle and knee in braced and unbraced conditions. The results showed that the semi-rigid support at the ankle joint can share the high impact force that would otherwise be inflicted on one’s lower extremity, thereby reducing the peak stress on the inferior articular surface of the tibia, menisci, and articular cartilages, as well as the horizontal force on the talus. Moreover, with knee bending, the elongated spring component at the knee joint can convert the impact kinetic energy into elastic potential energy of the spring; meanwhile, the retractive force generated by the spring also provides a more balanced interaction between the menisci and articular cartilages. This biomechanical analysis can accordingly provide inspiration for new approaches to place human lower extremities at lower risk during landings.

scholarly journals Biomechanics of Calcaneus Impacted by Talus: A Dynamic Finite Element Analysis

2021 ◽  
Author(s):  
Mengquan Huang ◽  
Bin Yu ◽  
Yubiao Li ◽  
Chunlai Liao ◽  
Jun Peng ◽  
...  
Keyword(s):  
Finite Element ◽  
Articular Surface ◽  
Three Dimensional ◽  
Peak Stress ◽  
Lateral Wall ◽  
Element Model ◽  
Calcaneal Fracture ◽  
Element Analysis ◽  
Average Maximum ◽  
The Impact

Abstract BackgroundThe biomechanics of calcaneus impacted by the talus are unclear. We aimed to evaluate the biomechanical effect of the talus impacting on the calcaneus at different falling speed, and analyze the factors affecting calcaneal fracture.Methods A finite element model including the talus, calcaneus and ligaments was built using a variety of three-dimensional reconstruction software. The method of explicit dynamics was used to analyze the process of the talus impacting the calcaneus. Stress values of the posterior, middle, and anterior subtalar articular surface(PSAS, ISAS, ASAS), the calcaneocubic articular surface(CAS), the bottom of the calcaneus(BC), the medial wall (MW)and lateral wall (LW) of the calcaneus were extracted. Stress quantity and distribution changes in various parts of the calcaneus changed with speed were analyzed.ResultsPosterior subtalar articular surface reached the peak stress first during the process of talus impacting the calcaneus. The stress was mainly concentrated on the PSAS, ASAS, MW and GA. Comparing with the speed of 5m/s, the average maximum stress increased in each region of the calcaneus were: PSAS 73.81%, ISAS 7.11%, ASAS 63.57%, GA 89.10%, LW 140.16%, CAS 140.58%, BC 137.67%, MW 135.99% at a speed of 10m/s. The regions where the stress were concentrated changed, and the magnitude and sequence of stress peaks of calcaneus changed with speed also during the impact.Conclusion The falling speed affected the value and distribution of stress of the calcaneus, which was the most important factor leading to a calcaneal fracture. The magnitude and sequence of stress peaks might be important factors in determining the beginning and direction of fracture lines.

scholarly journals Biomechanical Design Application on the Effect of Different Occlusion Conditions on Dental Implants with Different Positions—A Finite Element Analysis

2020 ◽  
Vol 10 (17) ◽  
pp. 5826
Author(s):  
Pei-Ju Lin ◽  
Kuo-Chih Su
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Dental Implants ◽  
Dental Implant ◽  
Reaction Force ◽  
Biomechanical Analysis ◽  
Element Analysis ◽  
Group Function ◽  
Implant System ◽  
The Impact

A dental implant is currently the most commonly used treatment for patients with lost teeth. There is no biomechanical reference available to study the effect of different occlusion conditions on dental implants with different positions. Therefore, the aim of this study was to conduct a biomechanical analysis of the impact of four common occlusion conditions on the different positions of dental implants using the finite element method. We built a finite element model that included the entire mandible and implanted seven dental implant fixtures. We also applied external force to the position of muscles on the mandible of the superficial masseter, deep masseter, medial pterygoid, anterior temporalis, middle temporalis, and posterior temporalis to simulate the four clenching tasks, namely the incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function (RGF). The main indicators measured in this study were the reaction force on the temporomandibular joint (TMJ) and the fixed top end of the abutment in the dental implant system, and the stress on the mandible and dental implant systems. The results of the study showed that under the occlusion conditions of RMOL, the dental implant system (113.99 MPa) and the entire mandible (46.036 MPa) experienced significantly higher stress, and the reaction force on the fixed-top end of the abutment in the dental implant system (261.09 N) were also stronger. Under the occlusion of ICP, there was a greater reaction force (365.8 N) on the temporomandibular joint. In addition, it was found that the reaction force on the posterior region (26.968 N to 261.09 N) was not necessarily greater than that on the anterior region (28.819 N to 70.431 N). This information can help clinicians and dental implant researchers understand the impact of different chewing forces on the dental implant system at different positions after the implantation.

scholarly journals Finite element analysis of the initial stability of arthroscopic ankle arthrodesis with three-screw fixation: posteromedial versus posterolateral home-run screw

2020 ◽  
Author(s):  
Sen Wang ◽  
Jian Yu ◽  
Dahang Zhao ◽  
Xiang Geng ◽  
Jiazhang Huang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Articular Surface ◽  
Large Diameter ◽  
Ankle Arthrodesis ◽  
Joint Surface ◽  
Element Analysis ◽  
Tibiotalar Joint ◽  
Initial Stability ◽  
The Impact

Abstract Objective: Arthroscopic ankle arthrodesis (AAA) is a standard surgical method for the treatment of advanced traumatic ankle arthritis and has become more popular due to its advantages. To fix the tibiotalar joint, the use of three percutaneous screws is considered to have better mechanical stability than the use of two screws. However, it is sometimes difficult to insert three screws because they might block each other due to the small area of the tibiotalar joint surface and the large diameter of the screws; few articles illustrate how to insert three screws without the screws disturbing each other. The purpose of this study is to explore possible screw configurations of tripod fixation in arthroscopic ankle arthrodesis that avoid the collision of screws and yield better biomechanical performance.Methods: We used the finite element method to examine the impact of different screw positions and orientations on the biomechanical characteristics of a three-dimensional (3D) ankle model. Maximum and average micromotion, pressure on the articular surface, and von Mises stress values of the tibia and the talus were used to evaluate the initial stability of the ankle.Results: Five kinds of three-screw configurations were identified, and finite element analysis results suggested that configurations with the posteromedial home-run screw presented lower micromotion (maximum: 17.96 ± 7.49 μm versus 22.52 ± 12.8 μm; mean: 4.88 ± 1.89 μm versus 5.19 ± 1.92 μm) (especially configuration 3) and better screw distributions on the articular surface than those with the posterolateral home-run screw.Conclusion: Screw configurations with the posteromedial home-run screw avoid collision and are more biomechanically stable than those with the posterolateral home-run screw. Thus, inserting the home-run screw through the posteromedial approach is recommended for clinical practice.

scholarly journals Finite element analysis of the initial stability of arthroscopic ankle arthrodesis with three-screw fixation: posteromedial versus posterolateral home-run screw

2020 ◽  
Author(s):  
Sen Wang ◽  
Jian Yu ◽  
Xin Ma ◽  
Dahang Zhao ◽  
Xiang Geng ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Articular Surface ◽  
Large Diameter ◽  
Ankle Arthrodesis ◽  
Joint Surface ◽  
Element Analysis ◽  
Tibiotalar Joint ◽  
Initial Stability ◽  
The Impact

Abstract Objective Arthroscopic ankle arthrodesis (AAA) is a standard surgical method for the treatment of advanced traumatic ankle arthritis and has become more popular due to its advantages. To fix the tibiotalar joint, the use of three percutaneous screws is considered to have better mechanical stability than the use of two screws. However, it is sometimes difficult to insert three screws because they might block each other due to the small area of the tibiotalar joint surface and the large diameter of the screws; few articles illustrate how to insert three screws without the screws disturbing each other. The purpose of this study is to explore possible screw configurations of tripod fixation in arthroscopic ankle arthrodesis that avoid the collision of screws and yield better biomechanical performance. Methods We used the finite element method to examine the impact of different screw positions and orientations on the biomechanical characteristics of a three-dimensional (3D) ankle model. Maximum and average micromotion, pressure on the articular surface, and von Mises stress values of the tibia and the talus were used to evaluate the initial stability of the ankle. Results Five kinds of three-screw configurations were identified, and finite element analysis results suggested that configurations with the posteromedial home-run screw presented lower micromotion (especially configuration 3) and better screw distributions on the articular surface than those with the posterolateral home-run screw. Conclusion Screw configurations with the posteromedial home-run screw avoid collision and are more biomechanically stable than those with the posterolateral home-run screw. Thus, inserting the home-run screw through the posteromedial approach is recommended for clinical practice.

scholarly journals To Evaluate the Influence of Implant Length on Stress Distribution of Osseointegrated Implant: A Three-Dimensional Finite Element Analysis: An In Vitro Study

2018 ◽  
Vol 6 (02/03) ◽  
pp. 097-105
Author(s):  
Neha Jindal ◽  
Manjit Kumar ◽  
Shailesh Jain ◽  
Navjot Kaur ◽  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises ◽  
The Impact ◽  
Implant Length ◽  
Nonsignificant Decrease

AbstractFinite element analysis is a technique for obtaining a solution to a complex mechanical problem by dividing the problem domain into a collection of much smaller and simpler domains (elements) in which the field variables can be interpolated with the use of shape functions. An overall approximated solution to the original problem is determined based on variational principles. Finite element analysis can provide a nondestructive system for quantifying stresses generated at the various interfaces of similar or dissimilar material. The finite element method also allows the study of the internal state of stress of components as well as stress patterns in two or more dissimilar materials adjacent to each other without affecting their independent behavior. This method is therefore ideally suitable for the biomechanical analysis of orthopedic, cardiovascular, and dental structures. In this study, implants of different length were numerically analyzed using bone-implant models developed from computed tomography-generated images of the mandible with osseointegrated implants. The impact of various lengths on stress distribution was examined using implants with a length of 8, 10, and 13 mm in mandibular first molar region under axial load of 100 N and buccolingual load of 50 N. All materials were assumed to be linearly elastic and isotropic. The Statistical Package for the Social Sciences software package was used for statistical analysis. Maximum von Mises stresses were located around the implant neck. It was demonstrated that there was statistically nonsignificant decrease in von Mises stress as the implant length increased. Within the limitations of this study, there was statistically nonsignificant decrease in von Mises stress as the implant length increased.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Response of Mild Steel Pipes Under High Mass Low Velocity Impacts

2014 ◽  
Author(s):  
Shamsoon Fareed ◽  
Ian May
Keyword(s):  
Finite Element ◽  
Mild Steel ◽  
Impact Energy ◽  
High Mass ◽  
Low Velocity ◽  
Element Analysis ◽  
Steel Pipes ◽  
Impact Tests ◽  
The Finite Element Analysis ◽  
The Impact

Accidental loads, for example, due to heavy dropped objects, impact from the trawl gear and anchors of fishing vessels can cause damage to pipelines on the sea bed. The amount of damage will depend on the impact energy. The indentation will be localized at the contact area of the pipe and the impacting object, however, an understanding of the extent of the damage due to an impact is required so that if one should occur in practice an assessment can be made to determine if remedial action needs to be taken to ensure that the pipeline is still serviceable. There are a number of parameters, including the pipe cross section and impact energy, which influence the impact behaviour of a pipe. This paper describes the response, and assesses the damage, of mild steel pipes under high mass low velocity impacts. For this purpose full scale impacts tests were carried out on mild steel pipe having diameter of 457 mm, thickness of 25.4 mm and length of 2000 mm. The pipe was restrained along the base and a 2 tonnes mass with sharp impactor having a vertical downward velocity of 3870 mm/sec was used to impact the pipe transversely with an impact energy of 16 kJ. It was found from the impact tests that a smooth indentation was produced in the pipe. The impact tests were then used for validation of the non-linear dynamic implicit analyses using the finite element analysis software ABAQUS. Deformations at the impact zone, the rebound velocity, etc, recorded in the tests and the results of the finite element analysis were found to be in good agreement. The impact tests and finite element analyses described in this paper will help to improve the understanding of the response of steel pipes under impact loading and can be used as a benchmark for further finite element modelling of impacts on pipes.

Flexible Flowline Walking Tendency on Seabed With Longitudinal Undulations and Transverse Gradients

2018 ◽  
Author(s):  
Graeme Roberts ◽  
T. Sriskandarajah ◽  
Gianluca Colonnelli ◽  
Arnaud Roux ◽  
Alan Roy ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Gradients ◽  
Radius Of Curvature ◽  
Bend Radius ◽  
Lateral Buckling ◽  
Element Analysis ◽  
Slip Tendency ◽  
Start Ups ◽  
The Impact

A method of carrying out a combined axial walking and lateral buckling assessment for a flexible flowline has been developed using finite element analysis. The method overcomes limitations of screening assessments which could be inconclusive when applied either to a flexible flowline on an undulating seabed with transverse gradients or to one that buckles during hydrotest. Flexible flowlines that were to be surface-laid on a seabed with longitudinal undulations and transverse gradients were assessed using the method. The flexible flowlines were simulated in their as-laid state, and the simulation incorporated hydrotest pressure and the pressure & temperature gradients and transients associated with multiple start-ups. The objective was to quantify the axial walking and lateral slip tendency of the flexible flowlines and the impact that walking might have on the connected end structures. The lateral buckle locations predicted by finite element analysis were compared to a post-hydrotest survey and the radius of curvature from analysis was compared to the minimum bend radius of the flexible.

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