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.

scholarly journals Analytical Calculation of the Tooth Surface Contact Stress of Cylindrical Gear with Variable Hyperbolic Circular-Arc-Tooth-Trace

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1318
Author(s):  
Yongqiao Wei ◽  
Rui Guo ◽  
Yongping Liu ◽  
Changbin Dong ◽  
Dawei Li ◽  
...  
Keyword(s):  
Contact Stress ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Element Analysis ◽  
Cylindrical Gear ◽  
Circular Arc ◽  
Contact Fatigue Strength ◽  
Maximum Contact Stress ◽  
Tooth Width ◽  
Maximum Contact

In order to theoretically research the tooth surface maximum contact stress of a Cylindrical Gear with Variable Hyperbolic Circular-Arc-Tooth-Trace (VH-CATT), the computing formula of maximum contact stress of VH-CATT cylindrical gear is investigated according to Hertz formula in this paper. Insufficient contact fatigue strength will lead to pitting corrosion, plastic deformation of tooth surface and other damages. Therefore, the maximum contact stress of tooth surface must be carried out. The contact stress calculation formula is particularly considering the effect of normal force, total carrying length, synthetical curvature radius, and position angle. The present work establishes analytical solutions to research the effect of different parameters for the contact stress of VH-CATT cylindrical gear incorporating elastic deformation on the tooth surface, and which have shown that the different module, transmission ratio, pressure angle, tooth width, and the cutter head radius have a crucial effect on the contact stress and contact ellipse of VH-CATT cylindrical gear along the tooth width direction. Moreover, a finite element analysis is carried out to verify the correctness of the theoretical computing formula of contact stress of VH-CATT cylindrical gear. By contrast with the theoretical calculated value and the stress value of finite element analysis, its error is very small. It is indicated that the derived formula of contact fatigue strength of VH-CATT cylindrical gear has high accuracy and can accurately reflect the real contact stress value of tooth surface, which is beneficial for research on tooth break reduction, pitting, wear resistance and fatigue life improvement of the VH-CATT cylindrical gear. The study results also have a certain reference value for the design and check calculation of the VH-CATT cylindrical gear.

Reduction of the Contact Stress in Internal Gear Pumps

1976 ◽  
Vol 98 (4) ◽  
pp. 1296-1300 ◽  
Author(s):  
J. R. Colbourne
Keyword(s):  
Contact Stress ◽  
Contact Stresses ◽  
Considerable Reduction ◽  
Tooth Contact ◽  
Maximum Contact Stress ◽  
Gear Pumps ◽  
Internal Gear ◽  
Maximum Contact

A method is described for calculating the tooth contact stresses in internal gear pumps, and it is shown that a considerable reduction can be achieved in the maximum contact stress by altering the proportions commonly used in existing pumps.

scholarly journals Design and manufacture of the novel drum worm pair

2020 ◽  
Vol 103 (4) ◽  
pp. 003685042098122
Author(s):  
Jingzi Zhang ◽  
Jin’ge Wang ◽  
Kai Wang
Keyword(s):  
Contact Stresses ◽  
Primary Objective ◽  
Structure Design ◽  
Worm Gear ◽  
The Novel ◽  
Bending Stress ◽  
Manufacturing Method ◽  
Design And Manufacture ◽  
Maximum Contact ◽  
Worm Drive

Although a significant amount of research on robot joint reducer was conducted, there are few systematic investigations on a novel joint reducer adopting inner worm-gear plane enveloping drum worm drive. To satisfy the development of modular robot joint, the primary objective of this paper was to systematically investigate the drum worm drive adopted in the novel joint reducer with integrated structure of drive, transmission, and support in the following aspects: meshing theory, design, analysis, and manufacture. According to the gear meshing theory, mechanical design method, classical mechanics, finite element method, and machining principle of virtual center distance, the systematic investigations around the drum worm pair applied in the novel joint reducer were conducted including the macro and micro meshing theory, structure design, mechanical and contact properties analyses, and manufacturing method. The novel joint reducer’s integrated structure was designed, and the drum worm pair’s mechanical and contact properties analyses were conducted, which showed: (1) the worm’s bending stress and deflection, worm-gear teeth’s shear stress and bending stress as well as the maximum contact stresses were all below their corresponding allowable values; (2) the maximum contact stresses appeared at the engage-in position of the worm pair opposing to the engaging-out position where the largest contact areas appeared. Then the manufacturing of drum worm’s spiral tooth was conducted via the modified 4-axis linkage CNC grinder according to the conjugate motion. Finally the novel joint reducer’s industrial prototype was assembled. The novel joint reducer with integrated structure of drive, transmission and support was designed and manufactured for the first time. The flowchart of design and manufacture of the reducer’s drum worm pair in this process was formulated, which provides a new insight on the research of joint reducers as well as other fields.

Finite Element Analysis for Gear Contact Based on UG and ABAQUS

2013 ◽  
Vol 442 ◽  
pp. 229-232 ◽  
Author(s):  
Li Mei Wu ◽  
Fei Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Tooth Surface ◽  
Element Analysis ◽  
Tooth Width ◽  
Gear Contact ◽  
Maximum Contact

According to the cutting theory of involute tooth profile, established an exact three-dimensional parametric model by UG. Used ABAQUS to crate finite element model for gear meshing. After simulated the meshing process, discussed the periodicity of the tooth surface contact stress. Based on the result of finite element analysis, made a comparison of the maximum contact stress between finite element solution and Hertz theoretical solution, analyzed the contact stress distribution on tooth width, and researched the effect of friction factor on contact stress. All that provided some theoretical basis for gear contact strength design.

Joint contact stress improves in dysplastic hips after periacetabular osteotomy but remains higher than in normal hips

2021 ◽  
pp. 112070002110364
Author(s):  
Jessica E Goetz ◽  
Holly D Thomas-Aitken ◽  
Sean E Sitton ◽  
Robert W Westermann ◽  
Michael C Willey
Keyword(s):  
Contact Mechanics ◽  
Contact Stress ◽  
Stance Phase ◽  
Periacetabular Osteotomy ◽  
Contact Stresses ◽  
Surgical Correction ◽  
Element Analysis ◽  
Walking Gait ◽  
Radiographic Measurements ◽  
Joint Contact

Aim: The purpose of this study was to use computational modeling to determine if surgical correction of hip dysplasia restores hip contact mechanics to those of asymptomatic, radiographically normal hips. Methods: Discrete element analysis (DEA) was used to compute joint contact stresses during the stance phase of normal walking gait for 10 individuals with radiographically normal, asymptomatic hips and 10 age- and weight-matched patients with acetabular dysplasia who underwent periacetabular osteotomy (PAO). Results: Mean and peak contact stresses were higher ( p < 0.001 and p = 0.036, respectively) in the dysplastic hips than in the matched normal hips. PAO normalised standard radiographic measurements and medialised the location of computed contact stress within the joint. Mean contact stress computed in dysplastic hips throughout the stance phase of gait (median 5.5 MPa, [IQR 3.9–6.1 MPa]) did not significantly decrease after PAO (3.7 MPa, [IQR 3.2–4.8]; p = 0.109) and remained significantly ( p < 0.001) elevated compared to radiographically normal hips (2.4 MPa, [IQR 2.2–2.8 MPa]). Peak contact stress demonstrated a similar trend. Joint contact area during the stance phase of gait in the dysplastic hips increased significantly ( p = 0.036) after PAO from 395 mm2 (IQR 378–496 mm2) to 595 mm2 (IQR 474–660 mm2), but remained significantly smaller ( p = 0.001) than that for radiographically normal hips (median 1120 mm2, IQR 853–1444 mm2). Conclusions: While contact mechanics in dysplastic hips more closely resembled those of normal hips after PAO, the elevated contact stresses and smaller contact areas remaining after PAO indicate ongoing mechanical abnormalities should be expected even after radiographically successful surgical correction.

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.

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.

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