Stress Analysis of the Skewed-Roller Slipping Clutch Based on Frictional Contact and Dynamic Equilibrium

2011 ◽  
Vol 86 ◽  
pp. 850-853 ◽  
Author(s):  
Ming Feng ◽  
Guang Rong Yan
Keyword(s):  
Stress Concentration ◽  
Frictional Contact ◽  
Power Transmission ◽  
Dynamic Equilibrium ◽  
Von Mises Stress ◽  
Relative Rotation ◽  
Profile Modification ◽  
Roller Profile ◽  
Von Mises ◽  
Reducing Stress

As a novel power transmission component, the skewed–roller slipping clutch (SRSC) produces resisting torque depending on relative rotation and sliding between askew arranged cylindrical rollers and specially curved races. In this paper, the surface contact stress and von Mises stress between the rollers and the races are calculated and the effects of roller profile modification on reducing stress concentration are investigated under frictional contact and dynamic equilibrium of the rollers and races.

Torque and Stress Characteristics of the Skewed-Roller Slipping Clutch Considering Frictional Contact and Dynamic Equilibrium

2014 ◽  
Vol 670-671 ◽  
pp. 784-789
Author(s):  
Ming Feng ◽  
Yong Li
Keyword(s):  
Contact Stress ◽  
Frictional Contact ◽  
Dynamic Equilibrium ◽  
Von Mises Stress ◽  
Relative Rotation ◽  
Stress Distributions ◽  
Surface Contact ◽  
Von Mises

The Skewed–Roller Slipping Clutch (SRSC) produces resistant torque which depends on the relative rotation and sliding between askew arranged cylindrical rollers and specially curved races. In this paper, the surface contact stress and von Mises stress distributions between the dub-off profiled rollers and races are calculated, with consideration given to the frictional contact and dynamic equilibrium of the rollers. The effects of the profiled roller’s parameters on the von Mises stress are investigated and the optimal modification parameters are calculated. In addition, the limiting resistant torque characteristics of the slipping clutch with optimal profiled rollers are discussed in detail.

scholarly journals Biomechanical Behavior Evaluation of a Novel Hybrid Occlusal Splint-mouthguard for Contact Sports: 3D-FEA

2021 ◽  
Author(s):  
Les Kalman ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Talita Suelen de Queiroz ◽  
João Paulo Mendes Tribst
Keyword(s):  
Stress Concentration ◽  
Mechanical Response ◽  
Compressive Loading ◽  
Von Mises Stress ◽  
Occlusal Splint ◽  
Total Deformation ◽  
Contact Sports ◽  
Biomechanical Behavior ◽  
Custom Made ◽  
Von Mises

Orofacial injuries are common occurrences during contact sports activities; however, there is an absence of data regarding the performance of hybrid occlusal splint mouthguards, especially during compressive loading. To evaluate the total deformation and stress concentration, a skull model was selected and duplicated to receive two different designs of mouthguard devices: one model received a conventional custom-made mouthguard (MG) with 4-mm thickness and the other received a novel hybrid occlusal splint-mouthguard (HMG) with the same thickness. Both models were subdivided into finite elements. The frictionless contacts were used, and a nonlinear analysis was performed simulating the compressive loading in occlusion. The results were presented in von-Mises stress maps (MPa) and Total Deformation (mm). A higher stress concentration in teeth was observed for the model with the conventional MG, while the HMG design displayed a promising mechanical response with lower stress magnitude. The HMG de-sign displayed a higher magnitude of stress on its occlusal portion than the MG design. The hybrid mouthguard (HMG) reduced (1) jaw displacement during chewing and (2) the generated stresses in maxil-lary and mandibular teeth.

scholarly journals Comparison of Load Carrying Capacity of Three and Four Lobed Polygonal Shaft and Hub Connection for Constant Grinding Diameter

2016 ◽  
Author(s):  
Ravi Bhatta ◽  
Wendy Reffeor
Keyword(s):  
Carrying Capacity ◽  
Power Transmission ◽  
Axial Stress ◽  
Von Mises Stress ◽  
Load Carrying Capacity ◽  
Interference Fit ◽  
Bending Load ◽  
Load Carrying ◽  
Von Mises ◽  
Conformal Contact

Polygonal shafts are used in power transmission as alternatives to keyed and splined shafts. They are designed using DIN standards. This research explores the loading strength of the standardized three lobed (P3G) and four lobed (P4C) polygonal shafts and hubs manufactured from the same stock size, subjected to torsional bending load at various fits. Due to complex conformal contact (nonlinear model) between the shaft and the hub, there is no analytical solution and, therefore, Finite Element Method had been used to determine the stresses, after validating experimentally and using the DIN standard. From the analysis, it was found that the hub experienced greater stress than the shaft in all cases and the major stress in a polygonal shaft and hub connection is the contact stress. The clearance fit was found to be the most detrimental fit and the interference fit to be the most suitable for larger power transmission. Owing to its small normal axial stress and hub displacement, the P4C clearance fit has its use in low power transmission where a sliding fit is a requirement. The maximum von Mises stress was located below the surface for P4C and P3G clearance fit, suggesting failure from pitting and fretting on these shafts. All of the stresses were found to be higher in P4C than P3G for similar loading. Therefore, for general use, the P3G profile with an interference fit is recommended.

MECHANICAL STRESS MAY CAUSE THE TEAR OF THE LABRUM IN ACETABULAR DYSPLASIA

2004 ◽  
Vol 08 (01) ◽  
pp. 35-41
Author(s):  
Hirotaka Sano ◽  
Norikazu Yamada ◽  
Shingo Maeda
Keyword(s):  
Stress Concentration ◽  
Mechanical Stress ◽  
Acetabular Dysplasia ◽  
The Body ◽  
Von Mises Stress ◽  
Center Edge ◽  
Dimensional Finite Element ◽  
Von Mises ◽  
Distal Border ◽  
The Relationship

In the current study, using the arthrogram, we developed two-dimensional finite element (FE) models of the human hip joint. To clarify the relationship between the stress distribution and the degree of acetabular dysplasia, three FE models were established and analyzed. The models varied only in the degree of the bony covering of the femoral head; i.e. the center-edge (CE) angle=20, 10, 0 degrees. An edge load (x=0 N, y=600 N) was then applied on the distal border of the femur to simulate the bearing of the body weight. In the CE=20 degree model, no definite stress concentration was seen at the site of the labrum. On the other hand, the stress concentration was seen from the attachment of the labrum to the superior aspect of the acetabulum in the CE=0 degree model. The site of stress concentration clearly corresponded to the lesions where the acetabular rim pathologies were seen in the clinical practice. Moreover, we found that the Von Mises stress increases dramatically with decreasing the CE angle at the attachment of the labrum. In the dysplastic hip, the mechanical stress increases significantly at the supero-lateral aspect of the acetabulum, which eventually leads to the tearing or detachment of the labrum.

scholarly journals A Contact Characteristic of Roller Bearing with Palm Oil-based Grease Lubrication

2021 ◽  
Vol 89 (2) ◽  
pp. 139-149
Author(s):  
Yap Jun Heng ◽  
Nurul Farhana Mohd Yusof ◽  
Lee Ann Yen ◽  
Shazlina Abd Hamid ◽  
Nurul Nadzirah Mohd Yusof
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Palm Oil ◽  
Frictional Contact ◽  
Roller Bearing ◽  
Rolling Contact ◽  
Von Mises Stress ◽  
The Coefficient Of Friction ◽  
Contact Characteristic ◽  
Von Mises

Grease lubricants are widely used in rolling contact applications to reduce friction between two rolling surfaces. Improper lubrication may cause high contact stress and deformation to the bearings and lead to machine failure The purpose of this study is to investigate the coefficient of friction produced by newly developed palm oil-based grease and to investigate the contact characteristics in lubricated roller bearings. In this work, the coefficient of friction of new greases was evaluated experimentally and the values were compared with the conventional mineral oil-based grease to investigate the friction performance. The friction test was performed using a four-ball tester. The finite element model was developed based on the roller bearing geometry and the simulation was carried out the evaluate the contact characteristic. The experimental result shows that the palm oil grease formulation A had the least coefficient of friction, followed by palm oil grease formulation B, mineral grease and food grade grease. This indicates that palm oil-based grease has the potential to be applied in rolling contact applications due to low friction characteristics. Finite element analysis shows that the maximum von Mises stress and total deformation for frictional contact are higher than the frictionless contact. For the frictional contact analysis with various lubricant COF, similar values were obtained with von Mises stress at 400.69 MPa and 3.4033×10-4 mm deformation. The finding shows that the small difference in grease COF did not affect the rolling contact. The finding also shows that the newly developed biodegradable grease has a similar performance in terms of rolling contact friction and contact characteristic in a condition that the bearing is operating in normal condition.

The Application of ANSYS Stress Concentration Analysis Technique to Etch Pit Analysis on Inhaul Cable

2012 ◽  
Vol 224 ◽  
pp. 295-302
Author(s):  
Yi Guo ◽  
Hua Bin Wen ◽  
Xiao Dong Pu ◽  
Chuan Hua Lu
Keyword(s):  
Stress Concentration ◽  
Steel Wire ◽  
Calculated Data ◽  
Von Mises Stress ◽  
Life Study ◽  
Etch Pit ◽  
Analysis Technique ◽  
Depth Increase ◽  
Von Mises ◽  
Wire Fatigue

Etch pit is a common local etch on inhaul cable. Etch pit on the surface of steel wire can produce pits and lead to the appearance of stress concentration due to geometrical discontinuity in the pits area on steel wire. After studying various stress concentration analysis techniques, it is concluded P-method is the best method suitable for the stress analysis of corrosive pits. The analysis results show that the Von. Mises stress at the bottom centre of pits and stress concentration factor in the pit first decreases and then increases with the depth increase of the pits. In the research on steel wire fatigue life, when paying attention to the maximum stress value, it still needs to consider the etch degree on steel wire section. The calculated data lay a certain foundation for the life study of inhaul cable.

Optimization of custom cementless stem using finite element analysis and elastic modulus distribution for reducing stress-shielding effect

2017 ◽  
Vol 231 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Gurunathan Saravana Kumar ◽  
Subin Philip George
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Stress Shielding ◽  
Von Mises Stress ◽  
Shielding Effect ◽  
Implant Design ◽  
Element Analysis ◽  
Von Mises ◽  
Reducing Stress

This work proposes a methodology involving stiffness optimization for subject-specific cementless hip implant design based on finite element analysis for reducing stress-shielding effect. To assess the change in the stress–strain state of the femur and the resulting stress-shielding effect due to insertion of the implant, a finite element analysis of the resected femur with implant assembly is carried out for a clinically relevant loading condition. Selecting the von Mises stress as the criterion for discriminating regions for elastic modulus difference, a stiffness minimization method was employed by varying the elastic modulus distribution in custom implant stem. The stiffness minimization problem is formulated as material distribution problem without explicitly penalizing partial volume elements. This formulation enables designs that could be fabricated using additive manufacturing to make porous implant with varying levels of porosity. Stress-shielding effect, measured as difference between the von Mises stress in the intact and implanted femur, decreased as the elastic modulus distribution is optimized.

scholarly journals Influence of Sagittal Root Positions on the Stress Distribution Around Custom-made Root-analogue Implants: A Three-dimensional Finite Element Analysis

2021 ◽  
Author(s):  
Chunping Lin ◽  
Hongcheng Hu ◽  
Junxin Zhu ◽  
Yuwei Wu ◽  
Qiguo Rong ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Class Ii ◽  
Class I ◽  
Von Mises Stress ◽  
Class Iii ◽  
Element Analysis ◽  
Custom Made ◽  
Root Position ◽  
Von Mises

Abstract Background: Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis.Methods: Six models were constructed and divided into two groups. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. Stress distributions under vertical and oblique loads of 100 N were analyzed.Results: Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stress in the bone around the custom-made root-analogue implants in this study was lower than around traditional implants reported in the literature. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress in the bone around the implants.Conclusions: The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

scholarly journals Influence of sagittal root positions on the stress distribution around custom-made root-analogue implants: a three-dimensional finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chunping Lin ◽  
Hongcheng Hu ◽  
Junxin Zhu ◽  
Yuwei Wu ◽  
Qiguo Rong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Class I ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Custom Made ◽  
Root Position ◽  
Von Mises ◽  
Von Mises Stresses

Abstract Background Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis. Methods The von Mises stresses in the bone around implants in different groups were compared by finite element analysis. Six models were constructed and divided into two groups through Geomagic Studio 2012 software. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. The von Mises stress distributions and the range of the stresses under vertical and oblique loads of 100 N were analyzed through ANSYS 16.0 software. Results Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stresses in the bone around the custom-made root-analogue implants in this study were lower than around traditional implants reported in the literature. The maximum von Mises stresses in this study were all less than 25 MPa in cortical bone and less than 6 MPa in cancellous bone. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress concentration in the bone around the implants. Conclusions The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

Stress Concentration Regions in Ceramic Ball Heads for Total Hip Replacement Considering Trauma-Like Loading

2005 ◽  
Vol 486-487 ◽  
pp. 185-188 ◽  
Author(s):  
Ho Sung Aum ◽  
M.C. Curiel ◽  
Daniel G. Carillo
Keyword(s):  
Stress Concentration ◽  
Hip Replacement ◽  
Stress Condition ◽  
Impact Load ◽  
Peak Load ◽  
High Stress ◽  
Friction Stress ◽  
Von Mises Stress ◽  
Critical Areas ◽  
Von Mises

A high stress condition in the hip system may cause fracture of the ball head. This failure may appear after a heavy accident such as sudden fall. The aim of this investigation is to make a computer simulated model of the hip system to evaluate the regions of stress concentration as well as the pressure in the stem-ball junction. 3D Non-Linear Finite Element Analyses were performed taking into consideration a high peak load to simulate trauma conditions. Ball heads from 22 to 36 mm in diameter were modeled, and also two sizes for taper lock were simulated to report their influence on the stresses over the critical areas of the ball head. Two different materials of common ball head ceramics (Alumina and Zirconia) were considered to evaluate its relation to the stresses produced. It was found that the ball head cone’s depth has major incidence in the stress concentration surrounding the stem when an impact load is applied, and that a deeper cone may offer a more relieved loading configuration when considering stress related parameters such as Von Mises stress, contact pressure and friction stress.

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