Modeling and Measuring Residual Stress in Autofrettaged Hollow Cylinders Through the Initial Strain Distribution Method

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Matteo Loffredo ◽  
Andrea Bagattini ◽  
Bernardo D. Monelli ◽  
Marco Beghini
Keyword(s):  
Residual Stress ◽  
Influence Function ◽  
Strain Distribution ◽  
Fe Simulation ◽  
Initial Strain ◽  
Experimental Setup ◽  
Fe Model ◽  
Distribution Method ◽  
Plastic Properties ◽  
Hollow Cylinders

The paper presents a method for modeling and measuring the residual stress (RS) field in axisymmetric autofrettaged elements. The method is based on the assumption that an Initial Strain Distribution (ISD), originated by the plastic strain previously induced during the autofrettage process, is the source of RSs. The ISD is the quantity to be evaluated and, after being determined, it can be used, by means of a dedicated finite element (FE) model, to evaluate the RS field in the component or in any part extracted from it. The ISD is obtained by elaborating the relaxed strains produced by cutting the autofrettaged component in incremental steps. The elaboration is based on solving a set of Fredholm's integral equations in which the unknown function is the ISD and the kernel is an Influence Function (IF) correlating the measured relaxed strain to the ISD. After a general discussion of the RS induced by the autofrettage and the effect of the plastic properties of the material under process, the methods for obtaining the relaxed strains by a rational experimental setup and the procedures for obtaining the IFs are presented and discussed. The whole methodology is applied to evaluate the RS field in a hollow cylinder for which the autofrettage was modeled by a FE simulation. The consistency of the method is verified and useful indications for the experimental activities were obtained.

Deforming Mechanisms of Two-Pass Drawing Process of an Aluminum Tube from Circular to Rectangle Section

2008 ◽  
Vol 575-578 ◽  
pp. 549-554 ◽  
Author(s):  
Guo Zheng Quan ◽  
Meng Han Wang ◽  
Jie Zhou ◽  
Ying Tong
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Strain Distribution ◽  
Fe Model ◽  
Drawing Process ◽  
Spring Back ◽  
Dynamics Model ◽  
Aluminum Tube ◽  
Drawing Die ◽  
Simulation Based

The aluminum tube with rectangle section can be produced by two-pass drawing process including non-plug and with-plug drawing. It is an effective method to study the deforming mechanisms by simulation, based on which the section varying of two-pass drawing got schemed and the relevant dies with reasonable dimensions got designed. The dynamics model and elasto-plastic FE model of the non-plug and with-plug drawing were established based on FEM software, then the simulation was performed. The sizing section of drawing die got optimized with angle β=178°, which eliminated instability. The influence of different semi-die angle 2 a on drawing load was researched, and a proper value of 2 a and 1 a was found. The touch boundary and touch-stress distribution of transitional drawing were achieved. Furthermore the residual stress and spring-back strain distribution after final drawing were achieved, which contributes to modifying the dimensions of rectangle sizing section.

scholarly journals The Effects of Shot Distance and Impact Sequence on the Residual Stress Field in Shot Peening Finite Element Model

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 462
Author(s):  
Zhou Wang ◽  
Ming Shi ◽  
Jin Gan ◽  
Xiaoli Wang ◽  
Ying Yang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Shot Peening ◽  
Dynamic Models ◽  
Fe Simulation ◽  
Residual Stress Distribution ◽  
Fe Model ◽  
Residual Stress Field ◽  
The Impact

In order to investigate the effect of shot distance and impact sequence on the residual stress distribution of 42CrMo steel in shot peening (SP) finite element (FE) simulation, 3D dynamic models with order dimple pattern and stochastic dimple pattern were established via ABAQUS/Explicit 6.14, and the simulation results were compared with experiments. The results show that shot overlap has a significant effect on the residual stress distribution of peened parts. Meanwhile, there is a threshold (related to SP parameter) for shot distance in the vertical and horizontal directions. When the shot distance is greater than the threshold in this direction, the residual stress distribution after SP tends to be stable. The impact sequence has almost no effect on the impact of a small number of shots, but this effect will appear when the number of shots increases. It is necessary to avoid shot overlap and continuous impact of adjacent dimples when the FE model is established; on this basis, the distance between shots and the number of layers of the shots can be reduced as much as possible without affecting the residual stress distribution. In addition, the comparison of simulation and experimental results shows that the residual stress evaluation area consistent with the experimental measurement is essential to obtain accurate residual stress distribution in the FE simulation process.

Study on bearing stiffness characteristics with residual stress in carburized layer

2020 ◽  
pp. 095440622096079
Author(s):  
Junshuai Liang ◽  
Ning Li ◽  
Jingyu Zhai ◽  
BaoGang Wen ◽  
Qingkai Han ◽  
...  
Keyword(s):  
Residual Stress ◽  
Contact Stiffness ◽  
Roller Bearing ◽  
High Load ◽  
Axial Stiffness ◽  
Fe Model ◽  
Low Load ◽  
Bearing Stiffness ◽  
Carburized Layer ◽  
Stiffness Characteristics

In this study, a layering method of carburized ring is presented. A finite element (FE) model for analyzing bearing stiffness characteristics is established considering the residual stress in the carburized layer. The residual stress in the carburized layer of a double-row conical roller bearing is tested and the influence of the distribution of residual stress in carburized layer on the bearing stiffness is investigated. Results show that the residual stress in the carburized layer increases the contact stiffness of the bearing by 5% in the low-load zone and 3% in the high-load zone. The radial stiffness of the bearing is increased by 5% in the low-load zone and 3% in the high-load zone. The axial stiffness is increased by 6%, and the angular stiffness increased by 4%. The larger the thickness of the carburized layer, the greater the residual compressive stress in the carburized layer, the deeper the position of the maximum residual stresses in the carburized layer will lead to the greater stiffness of the bearing.

scholarly journals Residual stresses in thermite welded rails: significance of additional forging

2020 ◽  
Vol 64 (7) ◽  
pp. 1195-1212
Author(s):  
B. Lennart Josefson ◽  
R. Bisschop ◽  
M. Messaadi ◽  
J. Hantusch
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welding Process ◽  
Surface Zone ◽  
Fe Model ◽  
Uneven Surface ◽  
Residual Stress Field ◽  
High Dynamic

Abstract The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. In both cases, large tensile residual stresses are found in the rail web at the weld. Additional forging may increase the risk of hot cracking due to an increase in plastic strains within the welded area.

Residual stress determination in surface treated alumina samples applying beam limiting masks

2009 ◽  
Vol 24 (S1) ◽  
pp. S77-S81 ◽  
Author(s):  
Thorsten Manns ◽  
André Rothkirch ◽  
Berthold Scholtes
Keyword(s):  
Residual Stress ◽  
Material Properties ◽  
Ccd Camera ◽  
Sample Surface ◽  
Real Space ◽  
Experimental Setup ◽  
Stress Determination ◽  
Small Gauge ◽  
Position Sensitive ◽  
To Receive

This paper deals with the implementation of a theoretically described method to determine residual stresses in real space directly by means of small gauge volumes. For this purpose, beam limiting masks were designed, manufactured, and investigated in first experiments. Image series taken with a position sensitive CCD camera demonstrate the ability to detect interferences from gauge volumes beneath the sample surface by defined slit geometries. The experiments show that due to the highly absorbing masks the amount of detectable photons is poor, and thus long exposure times are necessary to receive suitable data. For increasing measurement depths (altering masks) a decrease in the intensity can be detected which leads to the assumption that the diffracted photons originate from deeper regions in the material. A model was developed to simulate the diffraction conditions with different mask layouts and material properties. Modeling yields consistent results with experimental data, and thus provides a basis for further improvements of the experimental setup and the realization and assessment of residual stress measurements.

Prediction of Welding Deformation and Residual Stress in a Multiply-Stiffened Plate

2016 ◽  
Author(s):  
Min Guo ◽  
Zhen Chen ◽  
Yu Luo
Keyword(s):  
Residual Stress ◽  
Base Plate ◽  
Welding Parameters ◽  
Fe Model ◽  
Stiffened Plate ◽  
Local Distortion ◽  
Model Combining ◽  
Single Side ◽  
Welding Sequences ◽  
Welding Processes

In this paper, welding induced deformation and residual stress of a multiply-stiffened plate is studied by means of sequentially coupled thermal elasto-plastic finite element method. For the purpose of enhancing calculation efficiency, the FE model combining shell and solid elements is employed in the analysis. A transient moving heat source is used in the numerical analysis to consider important welding parameters such as heat input, welding speed and welding sequences. The welding processes of three stiffeners being attached to a base plate by single-side welds are simulated according to assembly configurations. The influence of three welding sequences and the position of weld foot on distortions and residual stress are discussed. The results demonstrate the different characteristics of residual distortion and stress in the multiply-stiffened plate by different welding sequences. The position of weld foot affects the local distortion of panel between two adjacent stiffeners.

Finite Element Analysis of Metal Flow of Finishing Groove in Hot Continuous Rolling Bar

2012 ◽  
Vol 510 ◽  
pp. 667-672
Author(s):  
Jia Lin Zhou ◽  
Chen Gang Pan ◽  
Xiao Yong Zhang
Keyword(s):  
Strain Distribution ◽  
Metal Flow ◽  
Dimensional Accuracy ◽  
Stress And Strain ◽  
Fe Model ◽  
Element Analysis ◽  
Iron And Steel ◽  
Expansion Angle ◽  
The Stability ◽  
Stress And Strain Distribution

This article established 3D FE model of dual-radius arc finishing groove and tangent expansion angle finishing groove using ANSYS / LS-DYNA software for Wuhan Iron and Steel plant Ф16 hot continuous bar, and analyzed metal flow pattern, stress and strain distribution of two types finishing grooves. The results show that surface stress and strain distribution of dual-radius arc finishing groove have better uniform than them of tangent expansion angle finishing groove, and dual-radius arc finishing groove ensures the stability of the rolled piece in finishing groove, improve the dimensional accuracy and surface quality of rolled finishing product.

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