Mathematical simulation of three-dimensional nonstationary temperature fields under electron-beam or laser welding by a movable heat source

2009 ◽  
Vol 38 (2) ◽  
pp. 169-176 ◽  
Author(s):  
V. E. Dzhashitov ◽  
V. M. Pankratov ◽  
A. V. Golikov
Keyword(s):  
Electron Beam ◽  
Heat Source ◽  
Laser Welding ◽  
Mathematical Simulation ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Nonstationary Temperature

Temperature Fields Generated by a Circular Heat Source: Solution of a Composite Solid of Two Different Isotropic Semi-Infinite Media

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Michael Emanuel ◽  
Avi Emanuel
Keyword(s):  
Heat Source ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Integral Form ◽  
Heat Fluxes ◽  
Inverse Laplace Transform ◽  
Temperature Fields ◽  
Circular Heat ◽  
Composite Solid ◽  
Infinite Media

Abstract The problem of a three-dimensional (3D) heat flow from a circular heat source (CHS) embedded inside a composite solid of two isotropic but different semi-infinite media is solved for the first time in this paper. This CHS asymmetrical measurement setup is useful when two identical samples are not available for measurement. Two different time-dependent temperature fields are derived for the composite semi-infinite media, as well as their corresponding heat fluxes. The derivation of the 3D solution uses first principles with basic assumptions and employs the Hankel and Laplace transforms. The Laplace inversion theorem is used to find the inverse Laplace transform of the temperature functions, since no tabulated inverse transform functions are available for this case. The solution is exact with no approximations and is given in an integral form, which can easily be evaluated numerically. This solution is a generic one and can be applied to more complex asymmetrical setups, such as the case involving thermal contact resistances.

Study on Welding Deformations of Shipboard of Container Vessel

2011 ◽  
Vol 488-489 ◽  
pp. 218-221
Author(s):  
Hong Li ◽  
Da Lu Qiu ◽  
Guang Lei Li ◽  
Hui Long Ren
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Plastic Strains ◽  
Out Of Plane ◽  
Inherent Strain ◽  
Nonlinear Behaviors ◽  
Plane Deformations

Residual plastic strains of the shipboard are the product of nonlinear behaviors during welding. Deformations of a welded shipboard injure the beauty of appearance of the ship, cause errors during the assembly of the shipboard and reduce the strength of the ship. Residual welding deformations of shipboard of a container vessel are studied in this paper. Nonlinear three dimensional transient temperature fields are analyzed by FEM first. The heat source is modeled as a moving heat flux following a Gaussian distribution. Then, applying the equivalent loads induced by the inherent strain on the shipboard, the final in-plane shrinkage and out-of-plane deformations are calculated. Being compared with the experimental results of deformations, the simulated results show mostly conformity.

Modeling of the Temperature Field during Electron Beam Welding of Aluminum Alloy by a Pre-Defined Keyhole

2007 ◽  
Vol 353-358 ◽  
pp. 2011-2014
Author(s):  
Yan Hong Tian ◽  
Chun Qing Wang ◽  
Dan Yang Zhu
Keyword(s):  
Temperature Field ◽  
Electron Beam ◽  
Heat Source ◽  
Electron Beam Welding ◽  
Three Dimensional ◽  
Source Model ◽  
Transient Temperature ◽  
Al Alloy ◽  
Welding Pool ◽  
Welding Line

The transient temperature field of Al alloy during electron beam welding (EBW) process was simulated using a three-dimensional finite element method. Different from the most previous models which were based on the assumption that the welding pool was solid and neglected the existence of keyhole by meshing the solid as a whole, a dynamic three-dimensional keyhole was applied in this model. The profile of the keyhole was ellipse and its size was determined before simulation based on the results of experiments. Following the heat source, the pre-defined keyhole moved along the welding line. A three-dimensional complex heat source model, including a modified Gaussian distribution source and a uniform source, was used in this study. The result shows that the shape of the keyhole had a direct effect on the temperature distribution and contribution to the special shape of the welding pool in EBW.

Thermofluid Properties of Ti-6Al-4V Melt Pool in Powder-Bed Electron Beam Additive Manufacturing

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
M Shafiqur Rahman ◽  
Paul J. Schilling ◽  
Paul D. Herrington ◽  
Uttam K. Chakravarty
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Heat Source ◽  
Thermal Behavior ◽  
Source Parameters ◽  
Three Dimensional ◽  
Full Density ◽  
Layer By Layer ◽  
Powder Bed ◽  
Melt Pool

Electron beam additive manufacturing (EBAM) is a powder-bed fusion additive manufacturing (AM) technology that can make full density metallic components using a layer-by-layer fabrication method. To build each layer, the EBAM process includes powder spreading, preheating, melting, and solidification. The quality of the build part, process reliability, and energy efficiency depends typically on the thermal behavior, material properties, and heat source parameters involved in the EBAM process. Therefore, characterizing those properties and understanding the correlations among the process parameters are essential to evaluate the performance of the EBAM process. In this study, a three-dimensional computational fluid dynamics (CFD) model with Ti-6Al-4V powder was developed incorporating the temperature-dependent thermal properties and a moving conical volumetric heat source with Gaussian distribution to conduct the simulations of the EBAM process. The melt pool dynamics and its thermal behavior were investigated numerically, and results for temperature profile, melt pool geometry, cooling rate and variation in density, thermal conductivity, specific heat capacity, and enthalpy were obtained for several sets of electron beam specifications. Validation of the model was performed by comparing the simulation results with the experimental results for the size of the melt pool.

Heat Source Model of Lap Laser Welding of Stainless Steel Vehicle

2011 ◽  
Vol 121-126 ◽  
pp. 3347-3351 ◽  
Author(s):  
Hong Xiao Wang ◽  
Chun Sheng Wang ◽  
Chun Yuan Shi ◽  
Zhi Yi Huang
Keyword(s):  
Stainless Steel ◽  
Heat Source ◽  
Laser Welding ◽  
Process Parameters ◽  
Production Efficiency ◽  
Three Dimensional ◽  
Source Model ◽  
Heat Source Model ◽  
Element Analysis ◽  
Welding Temperature

Resistance spot welding (RSW) is being taken place by partial lap laser welding for the poor surface quality and bad airtight due to the pressure of electrodes. The shape of partial lap laser welding is similar to the vase. When the penetration of the joint is in a certain range, there is no welding trace on the outer surface. Laser welding temperature field numerical analysis based on Abaqus finite element analysis software is committed to obtain a suitable range of process parameters to improve production efficiency and automation by determining the joint penetration. To master the laser lap welding of stainless steel weld penetration state, the combination of three-dimensional positive cone + three-dimensional inverted cone + half-ellipsoid heat source model was established simulating stainless steel lap laser weld pool shape and forecasting the range of process parameters .

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

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