scholarly journals Analytical Modeling and Optimization of Logarithmic Sprag Clutch Considering Profile Modification

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Chuang Huang ◽  
Yongqiang Zhao ◽  
Ming Liu
Keyword(s):  
Analytical Model ◽  
Contact Stress ◽  
Low Cycle Fatigue ◽  
Kriging Model ◽  
Friction Model ◽  
Design Parameters ◽  
Rate Dependency ◽  
Profile Modification ◽  
Maximum Contact Stress ◽  
Maximum Contact

A new analytical model of a logarithmic sprag clutch considering profile modification is proposed to reflect the effect of profile parameters on the dynamic contact pressure distribution during the engagement, especially the edge stress of a sprag roller. In the model, a nonlinear iteration method of normal force including the logarithmic profile model with three parameters and structural deformations of races is given. The alternate friction model considering stationary and rate-dependency friction is formulated and applied in the contacts between the sprag rollers and races. Then, the kriging model describing the relationship between the maximum contact stress throughout the engagement and the profile parameters is established and validated, and the kriging-based optimization of the design parameters is proposed using genetic algorithms. In subsequent analysis, based on the presented analytical model and optimization process, the maximum contact stress throughout the engagement can decrease greatly through optimizing the profile parameters. Therefore, the results of the present paper could aid in the design of the logarithmic sprag clutch and help avoid end crush failure and low cycle fatigue of the sprag roller.

Contact Stress in a Gerotor Pump

2003 ◽  
Author(s):  
P. Javier Gamez-Montero ◽  
Esteve Codina
Keyword(s):  
Contact Stress ◽  
Measurement Techniques ◽  
Design Parameters ◽  
Prototype Model ◽  
Gear Pump ◽  
Gear Teeth ◽  
2D Simulation ◽  
Maximum Contact Stress ◽  
Gerotor Pump ◽  
Maximum Contact

The aim of the first part of this paper is to reach the optimum design parameters of a gear set when it works as part of an internal gear pump type gerotor. The performance of the gear teeth and the whole gear set are evaluated through analytical studies to obtain the maximum contact stress in gear teethe and the volumetric characteristics. Several gear sets have been examined and the results are presented. The aim of the second part of the this paper is to documents a better understanding of the performance of a crankshaft mounted gerotor pump for IC engines lubrication. Modeling, simulation and experimental work have been examined for a specific unit. A preliminary 2D simulation is carried out by using the Finite Element Method (FEX) to calculate the maximum contact stress. At the testing phase, a prototype model of the gear set provides the maximum contact stress on a pair of teeth by using photoelasticity measurement techniques. The results are exposed and discussed and possible alterations are proposed.

scholarly journals Analysis and Optimization of Static Contact Characteristics of Heavy-Duty Tracked Vehicle Rollers

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
He Tian ◽  
Yi Fang ◽  
Shuai Wang ◽  
Zeren Chen ◽  
Chuliang Yan
Keyword(s):  
Contact Stress ◽  
Contact Structure ◽  
Kriging Model ◽  
Heavy Duty ◽  
Tracked Vehicle ◽  
Maximum Contact Stress ◽  
Static Contact ◽  
The Difference ◽  
Design And Manufacture ◽  
Maximum Contact

The static contact characteristics of heavy-duty tracked vehicle roller and track plate contact structure are analyzed, and the influence mechanism of the roller’s shape parameters on the contact stress is studied. According to the Hertz contact theory, a mathematical model of the roller and track plate contact is established. The contact structure model is established in ANSYS software, and the simulation results are compared with the Hertz theory results to verify each other. In the parameter optimization section for the roller and track plate, based on the Hertz stress calculation formula, a new method is proposed to establish a roller and track plate Kriging model and to globally optimize the model by the genetic algorithm (GA). After that, the relationship among the track roller radius R 1 , the track roller rim radius r 1 , and the track plate rim radius r 2 is analyzed. The results show that the difference between the radius of the rim of the roller and the track plate and the radius of the roller rim both affect the maximum contact stress. Changing the plane contact into the curved surface contact can reduce the maximum contact stress by 33%. This study can provide a reference for the design and manufacture of supporting track rollers and track plates.

scholarly journals Development of a nomogram to predict the contact stress between an I-girder and a support roller

2021 ◽  
Vol 9 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Thanin Chanmalai ◽  
Byungik Chang ◽  
Kevin Misaro ◽  
Saron Hagos ◽  
Thippesh Bethur Hanumanthareddy
Keyword(s):  
Numerical Modeling ◽  
Contact Stress ◽  
Contact Stresses ◽  
Primary Objective ◽  
Steel Bridge ◽  
Element Analysis ◽  
Maximum Contact Stress ◽  
Environmentally Sensitive Areas ◽  
Support Roller ◽  
Maximum Contact

The incremental launching method (ILM) is an efficient method of bridge construction primarily suited for environmentally sensitive areas. However, during the bridge launching, there are significant contact stresses between the launching system and the steel bridge girders. These substantial contact stresses can cause damage both on, and just under, the girder surface. Although Hertz contact theory solutions may give an insight into the problem, the accuracy is uncertain due to the presence of complex geometries, loads, and material properties. The complicated structural systems need to rely on numerical modeling such as the finite element analysis which are not always available. The primary objective of this study is to estimate the relationship of the maximum contact stress between an I-girder and a roller using a nomogram. The nomogram is built based on a parametric study with various roller dimensions and loads by numerical modeling. The maximum contact stress from the nomogram can be a useful tool in designing a bridge girder on a support roller.

Validation of a Finite Element Humeroradial Joint Model of Contact Pressure Using Fuji Pressure Sensitive Film

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sunghwan Kim ◽  
Mark Carl Miller
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Contact Area ◽  
Axial Loads ◽  
Contact Areas ◽  
Pressure Sensitive ◽  
Maximum Contact Stress ◽  
Sensitive Film ◽  
Pressure Sensitive Film ◽  
Maximum Contact

A finite element (FE) elbow model was developed to predict the contact stress and contact area of the native humeroradial joint. The model was validated using Fuji pressure sensitive film with cadaveric elbows for which axial loads of 50, 100, and 200 N were applied through the radial head. Maximum contact stresses ranged from 1.7 to 4.32 MPa by FE predictions and from 1.34 to 3.84 MPa by pressure sensitive film measurement while contact areas extended from 39.33 to 77.86 mm2 and 29.73 to 83.34 mm2 by FE prediction and experimental measurement, respectively. Measurements from cadaveric testing and FE predictions showed the same patterns in both the maximum contact stress and contact area, as another demonstration of agreement. While measured contact pressures and contact areas validated the FE predictions, computed maximum stresses and contact area tended to overestimate the maximum contact stress and contact area.

The Effects of Load on the Radial Bearing Properties of Pre-Loaded Cylindrical Roller Bearings

2011 ◽  
Vol 130-134 ◽  
pp. 2306-2310
Author(s):  
Yan Gang Wei ◽  
Meng Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Stress ◽  
Radial Load ◽  
The Finite Element Method ◽  
Roller Bearings ◽  
Radial Stiffness ◽  
Maximum Contact Stress ◽  
Maximum Contact ◽  
Cylindrical Roller

According to the theory of contact mechanics, the radial stiffness, the maximum contact stress, and the maximum radial load of pre-loaded cylindrical roller bearings, including both solid roller and hollow roller bearings, are calculated with the finite element method. The effects of load on the radial stiffness, the maximum contact stress, and the maximum radial load of bearing are analyzed. The analysis results show that the effect of load on the radial stiffness is complex. Under the different magnitude loads, the effects of both hollowness and interference magnitude on the radial stiffness and on the maximum contact stress are not same. Thus the effects of load magnitude must be considered in the design and application of pre-loaded cylindrical roller bearings.

Sealing performance and fatigue life of the fracturing packer rubber of various materials

2019 ◽  
Vol 233 (17) ◽  
pp. 6157-6166 ◽  
Author(s):  
Fuying Zhang ◽  
Haoche Shui ◽  
Jun-Mei Yang
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Contact Stress ◽  
Field Experiments ◽  
Structural Parameters ◽  
Element Model ◽  
Rubber Seal ◽  
Maximum Contact Stress ◽  
Different Temperatures ◽  
Maximum Contact

The finite element model of four packer rubber materials was established by using ABAQUS and FE-SAFE software. The initial sealing load (the load is the pressure) was 11.85 MPa, and the working load was 58.15 MPa. The sealing evaluation coefficient, maximum contact stress, and fatigue life value of four material packer rubbers were considered when considering temperature changes and fatigue unit nodes. The results show that when the working load and the structural parameters of the rubber are the same, the sealing evaluation coefficient of the four material rubber increases with the increase of temperature. When the working temperature reaches 125 ℃, the value of the rubber seal evaluation coefficient of the HNBR material is the largest, and the value of the rubber seal evaluation coefficient of the EPDM material is the smallest. Similarly, the maximum contact stress of the four material rubbers increases with increasing temperature. When the temperature reaches 125 ℃, the maximum contact stress of the HNBR material is the largest, and the maximum contact stress of the EPDM material is the smallest. The rubber of the four materials increase the fatigue life value with the increase in the temperature within the operating temperature range studied. When the temperature is lower than 120 ℃, the fatigue life value of the HNBR material rubber is the largest. When the temperature is higher than 120 ℃, the fatigue life value of the CR material rubber is the largest. Regardless of the temperature change, the fatigue life value of the EPDM is the smallest. By comparing the results of field experiments with the results of finite element models, the two are found to have good consistency, which verifies the validity and feasibility of the model. The research results have important guiding significance for the fatigue life prediction of various material packer rubbers under different temperatures.

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