The Study of Finite Element Simulation for Cooling after Heating Process of Rail

2015 ◽  
Vol 667 ◽  
pp. 224-230
Author(s):  
Feng Qin Yu ◽  
Jun Wang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Element Model ◽  
Heating Process ◽  
Air Cooling ◽  
Water Cooling ◽  
Heating And Cooling ◽  
Suitable Heat Treatment ◽  
Interior Stress ◽  
Dimension Stability

Because of the non-uniformity of the section shape of rail and complexity of its temperature changing, the degree of thermal expansion and contraction of section must be different which leads to the interior stress is produced inevitable in it. The residual stress in rail is elastic stress and its maximum value is elastic limit stress. They affect the dimension stability, mechanical property, deformation and etc. And it is the important factor of rail quality. This paper builds a finite element model of temperature field through the MSC.Marc software during the process of heating and cooling of 55Q rail, which simulates the rail stress field of air cooling and water cooling. Our paper conducts the experiments on the rails of same material and condition and also selects the temperature and stress of appointed nodes to analyze them. The results of experiments and simulations are very identical. Simulating the residual stress of air cooling and water cooling, the result is that residual stress of water cooling is bigger than that of air cooling. This consequence gives the reference for planning the suitable heat treatment and improving the service life.

Numerical Simulation of the Effects of Scanning Velocity on the Process of Laser Transformation Hardening on the Inner Wall of Pump Barrel

2012 ◽  
Vol 502 ◽  
pp. 217-221 ◽  
Author(s):  
Zhe Zhang ◽  
Bin Han ◽  
Yong Wang ◽  
Nan Nan Wang
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Element Model ◽  
Mechanical Parameters ◽  
Scanning Velocity ◽  
Hardened Zone ◽  
Heating And Cooling ◽  
Laser Transformation Hardening ◽  
Maximum Heating

This study establishes a 3-D finite element model for the numerical simulation of laser transformation hardening on inner wall of pump barrel through a finite element code-SYSWELD. The change of thermal mechanical parameters with temperature is considered. The temperature field, metallurgy transformation and distribution of residual stress are predicted. The effect of scanning velocity on the temperature, martensite fraction and distribution of residual stress are studied. The results show that peak temperature in the hardened zone reaches to 1067.0°C and the maximum heating and cooling rate of hardened zone are 1.24×104°C/s and 3.68×103°C/s. After treatment, martensite can be obtained as a main phase in the hardened zone whose fraction increases with the decrease of scanning velocity. Compressive stress could be acquired in the hardened zone while the peak of tensile stress exists in the HAZ.

Numerical Simulation of the Effects of Preheating on Electron Beam Additive Manufactured Ti-6Al-4V Build Plate

2016 ◽  
Vol 879 ◽  
pp. 274-278 ◽  
Author(s):  
Jun Cao ◽  
Philip Nash
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Cross Section ◽  
Element Model ◽  
Normal Direction ◽  
Thermal Residual Stresses ◽  
Longitudinal Residual Stress ◽  
Middle Cross Section

In an earlier study, a 3-D thermomechanical coupled finite element model was built and experimentally validated to investigate the evolution of the thermal residual stresses and distortions in electron beam additive manufactured Ti-6Al-4V build plates. In this study, an investigation using this robust and accurate model was focused on an efficient preheating method, in which the electron beam quickly scanned across the substrate to preheat the build plate prior to the deposition. Various preheat times, beam powers, scan rates, scanning paths and cooling times (between the end of current preheat scan/deposition layer and the beginning of the next preheat scan/deposition layer) were examined, and the maximum distortion along the centerline of the substrate and the maximum longitudinal residual stress along the normal direction on the middle cross-section of the build plate were quantitatively compared. The results show that increasing preheat times and beam powers could effectively reduce both distortion and residual stress for multiple layers/passes components.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

scholarly journals X-ray nanodiffraction analysis of stress oscillations in a W thin film on through-silicon via

2016 ◽  
Vol 49 (1) ◽  
pp. 182-187 ◽  
Author(s):  
J. Todt ◽  
H. Hammer ◽  
B. Sartory ◽  
M. Burghammer ◽  
J. Kraft ◽  
...  
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Finite Element ◽  
Diffraction Data ◽  
Element Model ◽  
Stress Distributions ◽  
Through Silicon Via ◽  
X Ray ◽  
Tangential Stresses ◽  
Stress Components

Synchrotron X-ray nanodiffraction is used to analyse residual stress distributions in a 200 nm-thick W film deposited on the scalloped inner wall of a through-silicon via. The diffraction data are evaluated using a novel dedicated methodology which allows the quantification of axial and tangential stress components under the condition that radial stresses are negligible. The results reveal oscillatory axial stresses in the range of ∼445–885 MPa, with a distribution that correlates well with the scallop wavelength and morphology, as well as nearly constant tangential stresses of ∼800 MPa. The discrepancy with larger stress values obtained from a finite-element model, as well as from a blanket W film, is attributed to the morphology and microstructural nature of the W film in the via.

A Fundamental Study of the Interaction of Residual Stress and Applied Loading on Fracture

2010 ◽  
Author(s):  
C. J. Aird ◽  
M. J. Pavier ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Crack Closure ◽  
Applied Load ◽  
Element Model ◽  
Residual Stress Field ◽  
Fundamental Study ◽  
Analytical Expression ◽  
Applied Loading

This paper presents the results of a fundamental finite-element based study of the crack-closure effects associated with combined residual and applied loading. First, an analytical expression for a representative two-dimensional residual stress field is derived. This residual stress field contains a central compressive region surrounded by an equilibrating tensile region. The analytical expression allows the size and shape of the field to be varied along with the magnitude of the residual stress. The residual stress field is then used as a prescribed initial stress field in a finite element model, in addition to a far field applied load. By introducing cracks of increasing length into these models, charts of stress-intensity-factor versus crack length are produced for different relative magnitudes of residual stress and applied load and for different sizes and shape of the residual stress field. These charts provide insight into the way in which crack-tip conditions evolve with crack growth under conditions of combined residual and applied loading and also enable conditions of crack closure and partial closure to be identified.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

Residual Stress Analysis Considering Phase Transformation and Transformation Plasticity for Heat-Treated Large Size Shaft

2016 ◽  
Vol 725 ◽  
pp. 647-652 ◽  
Author(s):  
Yusuke Yanagisawa ◽  
Yasuhiro Kishi ◽  
Katsuhiko Sasaki
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Phase Transformation ◽  
Air Cooling ◽  
Water Cooling ◽  
Stress Distributions ◽  
Transformation Plasticity ◽  
Large Size ◽  
Heat Treated ◽  
Good Agreement

The residual stress distributions of the forgings after both water-cooling and air-cooling were measured experimentally. The residual stress occurring during the heat-treatment was also simulated considering the phase transformation and the transformation plasticity. A comparison of the experiments with the simulations showed a good agreement. These results shows that the transformation plastic strain plays an important role in the heat treatment of large forged shafts.

Research on the Straightening Deformation Process of the Residual Stress of the Numerical Simulation for Different Kinds of Heavy Rail

2012 ◽  
Vol 430-432 ◽  
pp. 492-496
Author(s):  
Yu Yan Liu ◽  
Hao Li ◽  
Lin Chen
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Deformation Process ◽  
Element Model ◽  
Regional Deformation ◽  
Distribution Rule ◽  
Deformation Area ◽  
The Finite Element Model ◽  
Heavy Rail

Through out the establishment of heavy rail entity model and the finite element model of straightening for different kinds of heavy rail after the residual stress in straightening investigated . Analysed U75V、U76CrRE、U71Mn and U75VM the four different kinds in 8+1 level straightening of the seven regional deformation area rail head, rail waist, rail base vertical stress distribution rule.

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