Analysis of Nonlinear Heat Transfer and Residual Stresses during Multi-Pass Welding of Penetration Assembly

2009 ◽  
Vol 417-418 ◽  
pp. 149-152 ◽  
Author(s):  
Hong Li ◽  
Li Li
Keyword(s):  
Residual Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Butt Welding ◽  
Time Dynamic ◽  
Transient Temperature Field ◽  
Dimensional Finite Element ◽  
Nonlinear Transient ◽  
Girth Welds ◽  
Three Dimensional Finite Element

Welding residual plastic strains and stresses cause errors during the assembly and reduce the strength of the structure. Based on an elastic-plastic-model, a three-dimensional finite element numerical simulation of multi-pass butt welding of a representative penetration assembly is carried out in this paper. The nonlinear transient temperature field and the real-time dynamic stresses field during multi-pass butt welding with girth welds are obtained. In the end, the residual stresses of the complicated stainless steel penetration structure are calculated by FEM software ANSYS.

Modelling of the laser surface nitriding of Ti-6Al-4V alloy—analysis of heat transfer and residual stresses

2001 ◽  
Vol 215 (3) ◽  
pp. 315-340 ◽  
Author(s):  
M Labudovic ◽  
R Kovacevic
Keyword(s):  
Residual Stresses ◽  
High Speed ◽  
Parametric Design ◽  
Three Dimensional ◽  
Laser Surface ◽  
Transient Temperature ◽  
X Ray Diffraction ◽  
Dimensional Finite Element ◽  
On Line ◽  
Three Dimensional Finite Element

A three-dimensional finite element modelling of the laser surface nitriding of Ti-6A1-4V alloy is presented. Design capabilities of ANSYS parametric design language (APDL) were employed for this purpose. The model calculates transient temperature profiles, the dimensions of fusion zone and residual stresses in the laser surface nitrided Ti-6A1-4V alloy. Model simulations are compared with experimental results, acquired on-line using an ultra-high-speed shutter camera which is able to acquire well-contrasted images of the molten pool, and off-line using metallographical and X-ray diffraction analyses which show very good agreement. The results are further discussed to provide directions for reducing the residual stresses, as well as for feedback and process control.

Analysis for Temperature Field and Stress of Concrete Volute Structure

2011 ◽  
Vol 90-93 ◽  
pp. 2418-2422
Author(s):  
Xiao Bing Sun ◽  
Xue Ping Peng
Keyword(s):  
Temperature Field ◽  
Optimization Design ◽  
Thermal Stresses ◽  
Heat Waves ◽  
Water Pressure ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Transient Temperature Field ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Study on temperature field and thermal stresses of a large volume concrete volute structure is important to prevent the concrete structure cracking caused by excessively tensile strains that result from the cold or heat waves and the internal water pressure. By use of the three dimensional finite element method, the displacements and stresses of a concrete volute under the external loads are calculated. The transient temperature field and the thermal stress distribution of the concrete volute caused by the cold or heat waves are obtained, and the thermo-structural coupling stress field analyses for some cases are completed detailly. The calculating results are the basis for the optimization design of the concrete volute structure.

Cyclic and Residual Stresses Generated in the UHMWPE Component of Total Knee Replacements During the Walking Cycle

1999 ◽  
Author(s):  
Raghu N. Natarajan
Keyword(s):  
Residual Stresses ◽  
Failure Modes ◽  
Contact Region ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Element Model ◽  
Clear Understanding ◽  
Dimensional Finite Element ◽  
Total Knee ◽  
Three Dimensional Finite Element

Abstract Fatigue due to cyclic stresses is one of the predominant failure modes seen in retrieved tibial polyethylene components. There is no clear understanding of the influence of knee kinematics on wear seen in retrieved samples. Magnitude, direction and location of the contact load at the tibial surface were taken from the measurement obtained from gait analysis of a patient with a total knee replacement and was input into a three dimensional finite element model of a tibial component. The analyses showed that stress fluctuations and stress reversals occur both on the surface and just below the surface in the posterior region of the component. Residual stresses were produced due to plastic deformation in the posterior contact region of the component.

Effect of Gear-Side Case-Hardening on Residual Stresses of Case-Hardened Gears

2000 ◽  
Author(s):  
Kouitsu Miyachika ◽  
Satoshi Oda ◽  
Hiroshige Fujio
Keyword(s):  
Residual Stresses ◽  
Three Dimensional ◽  
Case Depth ◽  
Case Hardening ◽  
3D Fem ◽  
Face Width ◽  
Dimensional Finite Element ◽  
The Face ◽  
Standard Pressure ◽  
Three Dimensional Finite Element

Abstract This paper presents a study on effects of the case depth, the case-hardened part, the face width, the rim thickness and the standard pressure angle on residual stresses of case-hardened gears. A heat conduction analysis and an elastic-plastic stress analysis for the case-hardening process of spur gears were carried out by the three-dimensional finite-element method (3D-FEM), and then residual stresses were obtained. It was found that the compressive residual stress σ*θ = 30° at Hofer’s critical section of the end of the face width is smaller in magnitude than that of the middle of the face width, and that the absolute value of σ*θ = 30° of the middle of the face width decreases owing to case-hardening the gear-side and the decreasing rate increases with an increasing case depth and a decreasing face width.

scholarly journals Three-dimensional finite element simulation of residual stresses in UIC60 rails during the quenching process

2017 ◽  
Vol 21 (3) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nejad Masoudi ◽  
Mahmoud Shariati ◽  
Khalil Farhangdoost
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Analysis Model ◽  
Element Analysis ◽  
Quenching Process ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The aim of this paper is to develop means to predict accurately the residual stresses due to quenching process of an UIC60 rail. A 3-D non-linear stress analysis model has been applied to estimate stress fields of an UIC60 rail in the quenching process. A cooling mechanism with water spray is simulated applying the elastic-plastic finite element analysis for the rail. The 3-D finite element analysis results of the studies presented in this paper are needed to describe the initial conditions for analyses of how the service conditions may act to change the as-manufactured stress field.

Three Dimensional Finite Element Analyses of Welding Residual Stresses of a Repaired Weld

2018 ◽  
Author(s):  
Mingya Chen ◽  
Weiwei Yu ◽  
Fei Xue ◽  
Francis Ku ◽  
Zhilin Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Fe Model ◽  
Dimensional Finite Element ◽  
Surge Line ◽  
Line Slope ◽  
Three Dimensional Finite Element

The objective of this study is to correct installation non-conformance of a surge line using the excavation and re-weld method which is widely used in nuclear power plants. The surge line with a backslope was not at the required design level after initial installation. In order to solve the problem, a repairing technology is shown as follows: the weld was successively excavated and welded again while the surge line slope was corrected with the help of jacks. Because many of the degradation mechanisms relevant to power plant components can be accelerated by the presence of welding residual stresses (WRS), the WRS caused by the repairing process need to be studied. In this paper, the WRS simulation technique employed in this project is sophisticated. It utilizes a 3-D finite element (FE) model, and simulates the weld sequencing and excavation. Moreover, the WRS simulation performed in this project not only uses the un-axisymmetric model, but also considers the deformation caused by the external jacking loads. The results show that the repairing process is effective, and strain damage induced by the welding repair is also acceptable.

Residual Stresses in Multilayer Ceramic Capacitors: Measurement and Computation

2003 ◽  
Vol 125 (4) ◽  
pp. 506-511 ◽  
Author(s):  
Jaap M. J. den Toonder ◽  
Christian W. Rademaker ◽  
Ching-Li Hu
Keyword(s):  
Residual Stresses ◽  
Computational Study ◽  
Three Dimensional ◽  
Sintering Process ◽  
Multilayer Ceramic Capacitors ◽  
Ceramic Capacitors ◽  
Dimensional Finite Element ◽  
Multilayer Ceramic ◽  
Thermomechanical Reliability ◽  
Three Dimensional Finite Element

In this paper, we present a combined experimental and computational study of the thermomechanical reliability of multilayer ceramic capacitors (MLCC’s). We focus on residual stresses introduced into the components during the cooling down step of the sintering process. The technique of microindentation turned out to be a useful method to measure the stresses locally. The computations were done with three-dimensional finite element simulations. We find that the cooling step introduces compressive in-plane stresses in the ceramic layers. There is reasonably good overall agreement between the residual stresses obtained from the indentation experiments and the numerical simulations. Some discrepancies do exist, though, for measurements on cross-sectioned MLCC’s. Possible reasons for the differences are discussed.

NONLINEAR IMPACT DYNAMIC ANALYSIS AND COMPARISON WITH EXPERIMENTAL DATA FOR THE SKID GEAR

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1403-1408 ◽  
Author(s):  
DONG-HYUN KIM ◽  
YU-SUNG KIM
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Landing Gear ◽  
Gear System ◽  
Dynamic Responses ◽  
Test Results ◽  
Dimensional Finite Element ◽  
Nonlinear Transient ◽  
Skid Landing Gear ◽  
Three Dimensional Finite Element

In this study, nonlinear crash analyses have been conducted for the skid landing gear of helicopter. The realistic configuration of skid landing gear system is considered. Detailed three-dimensional finite element model with variable thickness and material nonlinearity is constructed for required impact design conditions. Advanced computational approach is used to conduct nonlinear transient impact dynamic analyses for different collision models. Characteristics of impact dynamic responses due to the ground crash are practically investigated in detail. It is also shown that the exact consideration of friction effect is very important to accurately predict the crash behavior of the skid type landing gear system. Finally, two typical landing conditions are analyzed and correlated with drop test results.

STRESS–STRAIN EVOLUTION IN CAST IN-738 SUPERALLOY SINGLE FUSION WELDS

2010 ◽  
Vol 02 (04) ◽  
pp. 807-826 ◽  
Author(s):  
E. A. BONIFAZ ◽  
N. L. RICHARDS
Keyword(s):  
Residual Stresses ◽  
Three Dimensional ◽  
Gta Welding ◽  
Plastic Strains ◽  
Nonuniform Temperature ◽  
Constant Heat ◽  
Temperature Changes ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Fusion Welds

A three-dimensional finite element elastic–plastic model was developed to study localized plastic strains and residual stresses that exist in a body that has previously been subjected to nonuniform temperature changes. The mechanical model was used to compute the evolution of plastic strains and residual stresses of welded material. The thermal gradient histories calculated during the GTA welding of cast IN-738LC alloys were imposed as load conditions on structural calculations. It can be clearly seen that at constant heat input, the level of plastic strains and the level of residual (Mises) stresses increase with welding speed. The model predicts highest residual stresses in regions of highest elastic strains, in agreement with conventional phenomenological material models where the macroscopic residual stress is always directly related to the macroscopic elastic strain. The highest residual stresses are located at the fusion line (where coarser dendrite secondary arm spacing exist); and the highest plastic strains are located at centerline (where finer dendrite secondary arm spacing exist). The calculations were performed using ABAQUS® FE code on the basis of a time-increment Lagrangian formulation.

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