Modeling Laser Travel and its Effects on Thermal Stresses in Laser Hardening of Steel

2015 ◽  
Author(s):  
Suhash Ghosh ◽  
Chittaranjan Sahay ◽  
Devdas Shetty
Keyword(s):  
Heat Source ◽  
Thermal Stresses ◽  
Target Material ◽  
Processing Parameters ◽  
Small Time ◽  
Laser Hardening ◽  
Fe Model ◽  
Aisi 4140 ◽  
Moving Plane ◽  
Variable Flux

To achieve a precise and controlled laser process, a thorough analysis of the thermal behavior of the material is necessary. The knowledge of the thermal cycles is important to ascertain suitable processing parameters, thus improving surface properties when the alloys are laser irradiated. In the present paper, a numerical simulation of the laser hardening process has been developed using the finite element (FE) code ABAQUS™ to solve the heat transfer equation inside the treated material (AISI 4140 steel). The thermal analysis is based on Jaeger’s classical moving heat source method by considering the laser beam as a moving plane (band/disc) heat source and the target material is a semi-infinite solid. However, the FE model, used to solve the governing equation, does not directly accommodate the moving nature of heat source. A reasonable approximation is to divide the laser travel on the substrate into many small time/load steps, and apply variable flux and boundary conditions in each time/load step. This approximates the quasi-steady state phenomena over the series of these time steps for the complete laser travel. This paper investigates the effects of the choice of time/load steps on the temperature and thermal stress evolution as well the computing times in the process.

Modeling Laser Travel and its Effects on Temperature Evolution in Laser Hardening of Hypoeutectoid Steel

2014 ◽  
Author(s):  
Suhash Ghosh ◽  
Chittaranjan Sahay
Keyword(s):  
Heat Source ◽  
Target Material ◽  
Processing Parameters ◽  
Small Time ◽  
Laser Hardening ◽  
Temperature Evolution ◽  
Fe Model ◽  
Aisi 4140 ◽  
Moving Plane ◽  
Variable Flux

To achieve a precise and controlled laser process, a thorough analysis of the thermal behavior of the material is necessary. The knowledge of the thermal cycles is important to ascertain suitable processing parameters, thus improving surface properties when the alloys are laser irradiated. In the present paper, a numerical simulation of the laser hardening process has been developed using the finite element (FE) code ABAQUS™ to solve the heat transfer equation inside the treated material (AISI 4140 steel). The thermal analysis is based on Jaeger’s classical moving heat source method by considering the laser beam as a moving plane (band/disc) heat source and the target material is a semi-infinite solid. However, the FE model, used to solve the governing equation, does not directly accommodate the moving nature of heat source. A reasonable approximation is to divide the laser travel on the substrate into many small time/load steps, and apply variable flux and boundary conditions in each time/load step. This approximates the quasi-steady state phenomena over the series of these time steps for the complete laser travel. This paper investigates the effects of the choice of time/load steps on the temperature evolution as well the computing times in the process.

scholarly journals FINITE ELEMENT ANALYSIS OF THE HEAT TRANSFER IN A PISTON

2020 ◽  
Vol 4 (1) ◽  
pp. 45-51
Author(s):  
Aisha Muhammad ◽  
Shanono Ibrahim Haruna
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Numerical Simulations ◽  
Internal Combustion Engines ◽  
Thermal Stresses ◽  
Maximum Temperature ◽  
Cylinder Wall ◽  
Fe Model ◽  
Piston Cylinder ◽  
Piston Head

The gas expansion process that takes place in a piston cylinder assembly have been used in numerous applications. However, the time-dependent process of heat transfer is still not fully apprehended as the expansion processes are complex and difficult due to the unsteady property of the turbulent flow process. Internal combustion Engines(ICE) designs are conducted with the aim of achieving higher efficiency in the thermal characteristics. To optimize these designs, numerical simulations are conducted. However, modelling of the process in terms of heat transfer and combustion is complex and challenging. For a designer to understand, calculate and quantify the thermal stresses and heat losses at different sections of the structure, understanding the piston-cylinder wall is needed. This study carried out a numerical simulations based on Finite Element Method (FEM) to investigatethe stresses in the piston, and temperature after loading. Appropriate boundary conditions were set on different surfaces for FE model. The study includes the effects of the thermal conductivity of the material of piston, cylinder wall, and connecting rod. Results show the maximum Von-misses stress occurs on the piston head with a value of 3486. 1MPa. The maximum temperature of the piston head and cylinder wall stands at 68.252 and 42.704 degree Celsius respectively.

An analytical approach of heat transfer modelling with thermal stresses in circular plate by means of Gaussian heat source and stress function

2021 ◽  
Author(s):  
Sangita Pimpare ◽  
Chandrashekhar Shalik Sutar ◽  
Kamini Chaudhari
Keyword(s):  
Boundary Condition ◽  
Heat Source ◽  
Circular Plate ◽  
Thermal Stresses ◽  
Research Work ◽  
Homogeneous Boundary Condition ◽  
Flux Boundary Condition ◽  
Differential Transform ◽  
The Mathematical Model

Abstract In the proposed research work we have used the Gaussian circular heat source. This heat source is applied with the heat flux boundary condition along the thickness of a circular plate with a nite radius. The research work also deals with the formulation of unsteady-state heat conduction problems along with homogeneous initial and non-homogeneous boundary condition around the temperature distribution in the circular plate. The mathematical model of thermoelasticity with the determination of thermal stresses and displacement has been studied in the present work. The new analytical method, Reduced Differential Transform has been used to obtain the solution. The numerical results are shown graphically with the help of mathematical software SCILAB and results are carried out for the material copper.

scholarly journals Thermal Stress Analysis of 3D Anisotropic Materials Involving Domain Heat Source by the Boundary Element Method

2019 ◽  
Vol 35 (6) ◽  
pp. 839-850
Author(s):  
Y. C. Shiah ◽  
Nguyen Anh Tuan ◽  
M.R. Hematiyan
Keyword(s):  
Boundary Element Method ◽  
Heat Source ◽  
Boundary Element ◽  
Thermal Stresses ◽  
Quadratic Function ◽  
Boundary Integral ◽  
Volume Integral ◽  
Direct Evaluation ◽  
Volume Heat ◽  
Element Method

ABSTRACTIn engineering applications, it is pretty often to have domain heat source involved inside. This article proposes an approach using the boundary element method to study thermal stresses in 3D anisotropic solids when internal domain heat source is involved. As has been well noticed, thermal effect will give rise to a volume integral, where its direct evaluation will need domain discretization. This shall definitely destroy the most distinctive notion of the boundary element method that only boundary discretization is required. The present work presents an analytical transformation of the volume integral in the boundary integral equation due to the presence of internal volume heat source. For simplicity, distribution of the heat source is modeled by a quadratic function. When needed, the formulations can be further extended to treat higher-ordered volume heat sources. Indeed, the present work has completely restored the boundary discretization feature of the boundary element method for treating 3D anisotropic thermoelasticity involving volume heat source.

scholarly journals MATERIAL AND THERMAL ANALYSIS OF LASER SINTERTED PRODUCTS

2013 ◽  
Vol 7 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Radovan Hudák ◽  
Martin Šarik ◽  
Róbert Dadej ◽  
Jozef Živčák ◽  
Daniela Harachová
Keyword(s):  
Thermal Analysis ◽  
Heat Stress ◽  
Thermal Stresses ◽  
Processing Parameters ◽  
Sintering Process ◽  
Input Processing ◽  
Thermal Simulations ◽  
The Impact ◽  
Selection Of

Abstract Thermal analysis of laser processes can be used to predict thermal stresses and consequently deformation in a completed part. Analysis of temperature is also the basic for feedback of laser processing parameters in manufacturing. The quality of laser sintered parts greatly depends on proper selection of the input processing parameters, material properties and support creation. In order to relatively big heat stress in the built part during sintering process, the thermal simulation and thermal analysis, which could help better understand and solve the issue of parts deformations is very important. Main aim of presented work is to prepare input parameters for thermal simulations by the use of RadTherm software (Thermoanalytics Inc., USA), directly during the sintering process and after the process and find out the impact of the heat stress on a final shape and size of the prototype. Subsequently, an annealing process of constructed products after DMLS could be simulated and specified.

scholarly journals Influence of Surface Preparation on the Interface of Al-Cu Joints Produced by Magnetic Pulse Welding

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 997 ◽  
Author(s):  
Omid Emadinia ◽  
Alexandra Martins Ramalho ◽  
Inês Vieira de Oliveira ◽  
Geoffrey A. Taber ◽  
Ana Reis
Keyword(s):  
Tensile Testing ◽  
Dissimilar Materials ◽  
Surface Preparation ◽  
Target Material ◽  
Processing Parameters ◽  
Magnetic Pulse ◽  
Magnetic Pulse Welding ◽  
Surface Conditions ◽  
Comprehensive Evaluations ◽  
Pulse Welding

Magnetic pulse welding can be considered as an advanced joining technique because it does not require any shielding atmosphere and input heat similar to conventional welding techniques. However, it requires comprehensive evaluations for bonding dissimilar materials. In addition to processing parameters, the surface preparation of the components, such as target material, needs to be evaluated. Different surface conditions were tested (machined, sand-blasted, polished, lubricated, chemically attacked, and threaded) using a fixed gap and standoff distance for welding. Microstructural observations and tensile testing revealed that the weld quality is dependent on surface preparation. The formation of waviness microstructure and intermetallic compounds were verified at the interface of some joints. However, these conditions did not guarantee the strength.

Finite Element Simulation of Steel Quench Distortion- Parametric Analysis of Processing Variables

2012 ◽  
Vol 1485 ◽  
pp. 29-34 ◽  
Author(s):  
F. A. García-Pastor ◽  
R.D. López-García ◽  
E. Alfaro-López ◽  
M. J. Castro-Román
Keyword(s):  
Finite Element ◽  
Martensitic Transformation ◽  
Internal Stress ◽  
Thermal Stresses ◽  
Stress Fields ◽  
Leaf Spring ◽  
Internal Stresses ◽  
Processing Temperature ◽  
Fe Model ◽  
Slow Cooling

ABSTRACTSteel quenching from the austenite region is a widely used industrial process to increase strength and hardness through the martensitic transformation. It is well known, however, that it is very likely that macroscopic distortion occurs during the quenching process. This distortion is caused by the rapidly varying internal stress fields, which may change sign between tension and compression several times during quenching. If the maximum internal stress is greater than the yield stress at given processing temperature, plastic deformation will occur and, depending on its magnitude, macroscopic distortion may become apparent.The complex interaction between thermal contraction and the expansion resulting from the martensitic transformation is behind the sign changes in the internal stress fields. Variations in the steel composition and cooling rate will result in a number of different paths, which the internal stresses will follow during processing. Depending on the route followed, the martensitic transformation may hinder the thermal stresses evolution to the point where the stress fields throughout the component may actually be reverted. A different path may support the thermal stresses evolution further increasing their magnitude. The cross-sectional area also affects the internal stresses magnitude, since smaller areas will have further trouble to accommodate stress, thus increasing the distortion. Additionally, the bainitic transformation occurring during relatively slow cooling rates may have an important effect in the final stress field state.A finite-element (FE) model of steel quenching has been developed in the DEFORM 3D simulation environment. This model has taken into account the kinetics of both austenite-bainite and austenite-martensite transformations in a simplified leaf spring geometry. The results are discussed in terms of the optimal processing parameters obtained by the simulation against the limitations in current industrial practice.

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