Fracture Reasons and Improvements for the Running Gear of Shearers

2012 ◽  
Vol 490-495 ◽  
pp. 2733-2737
Author(s):  
Chun Yu Song ◽  
Jing Ru Liu ◽  
Xiu Juan Zhang
Keyword(s):  
Finite Element ◽  
Internal Stress ◽  
Contact Force ◽  
Maximum Stress ◽  
Contact Analysis ◽  
Finite Element Models ◽  
Elastic Contact ◽  
Gear Teeth ◽  
Calculation Results ◽  
Contact Spots

Running traction mechanism of shearers is adopted as the analysis object in this paper. The finite element models for the elastic contact analysis between the running gears and pin-rails are created. When the gears are running, the variation principles of contact spots, contact force, and internal stress for the gears and pin-rails at the different contact positions are analyzed. The calculation results show that the maximum stress is located at the edges of the gear teeth for the different contact positions. When the teeth are loaded with the repeated large stress, cracks are produced at the tooth edges at first and then are growing. The tooth breakage is produced at last. Gear chamfers using two circulars at the tooth edges can change the location of the maximum stress and the maximum MISES stress can be reduced by 20% or more. Therefore, the fracture problem of gear teeth is solved basically.

Study on the Effect of Ways of Gear Relief on Contact Force of Teeth Face

2011 ◽  
Vol 415-417 ◽  
pp. 66-70
Author(s):  
Yong Ma ◽  
Qi Huang ◽  
Tian Ji ◽  
Zhi Feng Lou
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Contact Analysis ◽  
Finite Element Models ◽  
Contact Method ◽  
Helical Gears ◽  
Profile Modification ◽  
Involute Gears ◽  
Main Basis ◽  
Better Than

An accurate finite element contact analysis of helical gears was done directly under ANSYS, while the integrated elastic deformation of the meshed teeth was extracted directly from the finite element contact analysis results, and considered as the main basis of the amount of tooth profile modification. Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models of two ways of modified gear are built. Under the same modified parameters, contact method is used on the proposed finite element models of gears by software LS-DYNA, and the effect of the two ways of gear relief on contact force on teeth face is analyzed. The results show that the effect of a pair of gears relief is better than one gear relief for linear and conic relief curve, and the effect of one gear relief is better than a pair of gears relief for cubic and sine relief curve. So dynamic simulation on modified involute gears has great significance for reducing contact force of teeth face of gears.

Study on Contact Force of Tooth Profile Modification

2011 ◽  
Vol 328-330 ◽  
pp. 451-456
Author(s):  
Yong Ma ◽  
Qi Huang ◽  
Zhi Feng Lou ◽  
Ke Hong Li
Keyword(s):  
Finite Element ◽  
Dynamic Simulation ◽  
Contact Force ◽  
Equivalent Stress ◽  
Finite Element Models ◽  
Contact Method ◽  
Elastic Contact ◽  
Profile Modification ◽  
Single Tooth ◽  
Contact Impact

Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models are built in UG and a new method of establishing relief gear models is proposed in this paper. Based on the theory of elastic, contact method is used on the proposed finite element models of gears by software LS-DYNA. Total contact force of teeth face, contact force of single tooth and equivalent stress on relief gears in different cases are obtained. The results show that contact impact existing in meshing between teeth of gears is ameliorated, contact force of tooth face and equivalent stress is reduced. The effect of cubic and sine relief curve is the best. So dynamic simulation on relief gears has great significance for reducing contact force between teeth faces of gears.

Wing-Fuselage Lug Stress Prediction Using Finite Element Method

2013 ◽  
Vol 393 ◽  
pp. 317-322
Author(s):  
Abdul Malik Hussein Abdul Jalil ◽  
Wahyu Kuntjoro
Keyword(s):  
Finite Element ◽  
Load Distribution ◽  
Applied Load ◽  
Maximum Stress ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Finite Element Software ◽  
Stress Prediction ◽  
Reaction Forces ◽  
The Individual

This paper describes the methodology to predict the stress level that occurs at the wing-fuselage lugs (joints). The finite element models of the wing, the wing lugs and the fuselage lugs were developed. Finite Element Analyses were performed using NASTRAN finite element software. CQUAD4 and BAR2 elements were used to represent the individual structures of the wing such as the ribs and stringers. The applied load was based on the symmetrical level flight condition. Once the load distribution acting at the wing had been calculated and applied, reaction forces at the nodes representing the wing lugs were obtained and these values applied to the lug models where the maximum stress value acting at the lugs was obtained.

Mechanics Analysis and Optimization of the Reachstacker Spreader

2014 ◽  
Vol 1078 ◽  
pp. 266-270
Author(s):  
Yu Feng Shu ◽  
Yong Feng Zheng
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Maximum Stress ◽  
Element Model ◽  
Static Strength ◽  
Operating Conditions ◽  
Mechanics Analysis ◽  
Calculation Results ◽  
Improvement Measures ◽  
The Finite Element Model

This paper establishes the finite element model of reachstacker spreader, makes static strength calculation under eight typical operating conditions with rated load, based on the calculation results, it points out the weaknesses of spreader and gives some corresponding improvement measures for the drawbacks. Further analysis shows that the maximum stress of improved spreader mechanism has reduced 10.1%, which demonstrates the effectiveness of improvements.

Finite Element Analysis for Nozzle With External Loads

2011 ◽  
Author(s):  
Hak-Sung Lee ◽  
Chang-Hoon Ha ◽  
Tae-Jung Park
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Pressure Vessel ◽  
Maximum Stress ◽  
Structural Integrity ◽  
Finite Element Models ◽  
Pressurized Water ◽  
Dimensional Finite Element ◽  
Maximum Stress Intensity ◽  
External Loads

Various kinds of nozzles are attached to a pressure vessel including Steam Generator (SG) in a pressurized water reactor plant. The downcomer feedwater nozzle on the upper vessel shell and the economizer feedwater nozzle in the lower vessel shell of the SG are representative nozzles which have a non axi-symmetric shape. In most cases, external loads composed with forces and moments are imposed on those nozzles during the plant operation. In order to evaluate structural integrity of junctures between the nozzles and vessels in compliance with the ASME Boiler and Pressure Vessel Code, Section III, it is essential to find the maximum stress intensity resulting from those loads. Welding Research Council (WRC) Bulletin 297 has been used to find the maximum stress intensity since it is not straightforward to calculate the stress intensity with a non axi-symmetric two dimensional finite element model. However, the compatibility of adopting WRC Bulletin 297 to nozzles which have a variety of geometries shall be considered. Moreover, the applicability of the stress intensity resulting from the bulletin should be into consideration when interested lines where stress intensity linearization is to be performed are not exactly consistent with the line defined in the Bulletin. In this study, the nozzles in cylindrical vessel shells are developed as three dimensional finite element models, which are loaded with unit forces and moments. The stress intensities from finite element models are investigated through a comparison of WRC Bulletin 297. In addition, a methodology to apply the stress intensity results from WRC 297 to different lines is proposed.

Research on the Influence of the Stiffening Plates on the Stress of Hold Hoop of Bent Cap

2019 ◽  
Vol 815 ◽  
pp. 223-228
Author(s):  
Qin Tian ◽  
Cheng Hao Hang ◽  
Yun Peng Zou ◽  
Zi Xin Wan
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stress Concentration ◽  
Structural Parameters ◽  
Great Influence ◽  
Finite Element Models ◽  
Finite Element Software ◽  
Bridge Steel ◽  
Calculation Results ◽  
Shell Finite Element

In order to improve the mechanical behaviour of bridge steel hoops, the plate shell finite element models of several steel hoops were established by using the general finite element software ABAQUS. Through changing the structural parameters of the stiffening plates, the influence of the stiffening plates on the mechanical properties of the steel hoops was explored. The calculation results show that the stress distribution at both ends of the steel hoop is uneven and there is a phenomenon of stress concentration. The spacing of stiffening plates has great influence on the mechanical properties of steel hoop. Some measures to improve the mechanical properties of steel hoop are given.

Fatigue Life Calculation of the in-Service Dented Pipeline

2011 ◽  
Vol 467-469 ◽  
pp. 1327-1332 ◽  
Author(s):  
Wu Ying ◽  
Peng Zhang ◽  
Wu Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
Pressure Variation ◽  
Finite Element Models ◽  
Test Results ◽  
Peak Period ◽  
Factors Affecting ◽  
Life Model ◽  
Calculation Results

Dent is one of the important factors affecting pipeline fatigue life, and it will greatly reduce the fatigue life of the pipeline in service. Based on a large number of foreign dented pipeline fatigue test results and fatigue life model, for the typical dent defect, using finite element method, various parameters are changed and finite element models are obtained under different conditions. According to many calculation results, a key ratio of peak period stress and pipeline pressure variation are obtained, which are substituted to the fatigue life model and the example are calculated.

Finite Element Contact Analysis of Locomotive Traction Gears

2012 ◽  
Vol 459 ◽  
pp. 19-24
Author(s):  
Jun Hua Bao ◽  
Wei Dong He
Keyword(s):  
Finite Element ◽  
Optimization Design ◽  
Contact Analysis ◽  
Software System ◽  
Stress Distributions ◽  
Ansys Software ◽  
Element Analysis ◽  
Solid Models ◽  
Calculation Results ◽  
Basic Parameters

The parametric solid models and assemble model are built in Pro/Engineer software system on the base of basic parameters of locomotive traction gears. The dedendum transition curves of teeth are fit by inputting the accurate coordinates of real curve of tooth that machined by gear hob after analyzing the envelopment processing of tooth. Assembling the driving and driven gears in Pro/Engineer system, and then the assemble model is imported into ANSYS software system, the settings of finite element analysis are defined, the finite element contact analysis of the driving and driven gears is done in ANSYS software. The accurate stress distributions of contact stress of teeth surfaces and the bending stress of dedendum of teeth are obtained base on the simulation calculations and post-processing in ANSYS. The calculation results are accurate compared with the real stress condition of teeth, so it can be the base of optimization design of gears for further research.

scholarly journals Strain Hardening From Elastic–Perfectly Plastic to Perfectly Elastic Flattening Single Asperity Contact

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Hamid Ghaednia ◽  
Matthew R. W. Brake ◽  
Michael Berryhill ◽  
Robert L. Jackson
Keyword(s):  
Finite Element ◽  
Contact Force ◽  
Material Model ◽  
Real Contact Area ◽  
Contact Radius ◽  
Elastic Contact ◽  
Elastic Deformations ◽  
Real Contact ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

For elastic contact, an exact analytical solution for the stresses and strains within two contacting bodies has been known since the 1880s. Despite this, there is no similar solution for elastic–plastic contact due to the integral nature of plastic deformations, and the few models that do exist develop approximate solutions for the elastic–perfectly plastic material model. In this work, the full transition from elastic–perfectly plastic to elastic materials in contact is studied using a bilinear material model in a finite element environment for a frictionless dry flattening contact. Even though the contact is considered flattening, elastic deformations are allowed to happen on the flat. The real contact radius is found to converge to the elastic contact limit at a tangent modulus of elasticity around 20%. For the contact force, the results show a different trend in which there is a continual variation in forces across the entire range of material models studied. A new formulation has been developed based on the finite element results to predict the deformations, real contact area, and contact force. A second approach has been introduced to calculate the contact force based on the approximation of the Hertzian solution for the elastic deformations on the flat. The proposed formulation is verified for five different materials sets.

scholarly journals Optimization of Nonlinear Hyperelastic Coefficients for Foot Tissues Using a Magnetic Resonance Imaging Deformation Experiment

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Marc Petre ◽  
Ahmet Erdemir ◽  
Vassilis P. Panoskaltsis ◽  
Thomas A. Spirka ◽  
Peter R. Cavanagh
Keyword(s):  
Magnetic Resonance Imaging ◽  
Finite Element ◽  
Magnetic Resonance ◽  
Soft Tissue ◽  
Internal Stress ◽  
Material Properties ◽  
Accurate Prediction ◽  
Finite Element Models ◽  
Resonance Imaging ◽  
Fat Pad

Accurate prediction of plantar shear stress and internal stress in the soft tissue layers of the foot using finite element models would provide valuable insight into the mechanical etiology of neuropathic foot ulcers. Accurate prediction of the internal stress distribution using finite element models requires that realistic descriptions of the material properties of the soft tissues are incorporated into the model. Our investigation focused on the creation of a novel three-dimensional (3D) finite element model of the forefoot with multiple soft tissue layers (skin, fat pad, and muscle) and the development of an inverse finite element procedure that would allow for the optimization of the nonlinear elastic coefficients used to define the material properties of the skin muscle and fat pad tissue layers of the forefoot based on a Ogden hyperelastic constitutive model. Optimization was achieved by comparing deformations predicted by finite element models to those measured during an experiment in which magnetic resonance imaging (MRI) images were acquired while the plantar surface forefoot was compressed. The optimization procedure was performed for both a model incorporating all three soft tissue layers and one in which all soft tissue layers were modeled as a single layer. The results indicated that the inclusion of multiple tissue layers affected the deformation and stresses predicted by the model. Sensitivity analysis performed on the optimized coefficients indicated that small changes in the coefficient values (±10%) can have rather large impacts on the predicted nominal strain (differences up to 14%) in a given tissue layer.

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