Three-Dimensional Thermal Analysis for Laser Assisted Milling of Silicon Nitride Ceramics Using FEA

2005 ◽  
Author(s):  
Xinwei Shen ◽  
W. J. Liu ◽  
Shuting Lei
Keyword(s):  
Silicon Nitride ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Operating Parameters ◽  
Beam Diameter ◽  
Transient Temperature Distribution ◽  
Failure Theory ◽  
Ceramic Machining ◽  
Laser Heat Source

Laser assisted machining (LAM) is one promising method for ceramic machining. In this paper, a three-dimensional heat transfer and thermal stress analysis is completed using commercial FEA software (ANSYS) to gain some insights on the thermal aspects for laser assisted milling. The transient temperature distribution was analyzed for a silicon nitride (Si3N4) ceramic workpiece undergoing a translating laser heat source which simulates the heating environment of the slot-milling operation with LAM. The effects of the operating parameters, such as laser power, laser beam diameter, laser preheat time and laser translating speed, were investigated. The thermal stresses induced from the steep temperature change and the effects of the operating parameters on thermal stresses were investigated. Additionally, the maximum-normal stress failure theory for brittle materials were employed to predict the possibility of cracking on ceramic workpiece due to thermal stresses.

A photothermoelastic investigation of transient thermal stresses in wing ribs

1972 ◽  
Vol 7 (2) ◽  
pp. 117-124 ◽  
Author(s):  
E Matsumoto ◽  
S Sumi ◽  
T Sekiya
Keyword(s):  
Temperature Distribution ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Composite Model ◽  
New Technique ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Transient Thermal

The photothermoelastic method of refrigeration has been used to study the problem of a long beam under transient temperature distribution and good correlation with the theoretical values has been obtained. The new technique for three-dimensional photothermoelasticity, which uses a composite model made of photoelastically sensitive and insensitive materials, is suggested for the analysis of idealized wing-rib structures.

A Three-Dimensional Finite Difference Solution for the Thermal Stresses in Railcar Wheels

1969 ◽  
Vol 91 (3) ◽  
pp. 891-896 ◽  
Author(s):  
G. E. Novak ◽  
B. J. Eck
Keyword(s):  
Computer Program ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Radial Temperature ◽  
Closed Form Solutions ◽  
Brake Application ◽  
History Of ◽  
Thin Disks

A numerical solution is presented for both the transient temperature and three-dimensional stress distribution in a railcar wheel resulting from a simulated emergency brake application. A computer program has been written for generating thermoelastic solutions applicable to wheels of arbitrary contour with temperature variations in both axial and radial directions. The results include the effect of shear stresses caused by the axial-radial temperature gradients and the high degree of boundary irregularity associated with this type of problem. The program has been validated by computing thermoelastic solutions for thin disks and long cylinders; the computed values being in good agreement with the closed form solutions. Currently, the computer program is being extended to general stress solutions corresponding to the transient temperature distributions obtained by simulated drag brake applications. When this work is completed, it will be possible to synthesize the thermal history of a railcar wheel and investigate the effects of wheel geometry in relation to thermal fatigue.

Direct observation of three-dimensional transient temperature distribution in SiC Schottky barrier diode under operation by optical-interference contactless thermometry (OICT) imaging

2022 ◽  
Author(s):  
Keiya Fujimoto ◽  
Hiroaki Hanafusa ◽  
Takuma Sato ◽  
Seiichiro HIGASHI
Keyword(s):  
Temperature Distribution ◽  
Schottky Barrier ◽  
Hot Spot ◽  
Local Heating ◽  
Three Dimensional ◽  
Schottky Barrier Diode ◽  
Transient Temperature ◽  
Optical Interference ◽  
Transient Temperature Distribution ◽  
Heating And Cooling

Abstract We have developed optical-interference contactless thermometry (OICT) imaging technique to visualize three-dimensional transient temperature distribution in 4H-SiC Schottky barrier diode (SBD) under operation. When a 1 ms forward pulse bias was applied, clear variation of optical interference fringes induced by self-heating and cooling were observed. Thermal diffusion and optical analysis revealed three-dimensional temperature distribution with high spatial (≤ 10 μm) and temporal (≤ 100 μs) resolutions. A hot spot that signals breakdown of the SBD was successfully captured as an anormal interference, which indicated a local heating to a temperature as high as 805 K at the time of failure.

scholarly journals Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method

2011 ◽  
Vol 32 (3) ◽  
pp. 191-200 ◽  
Author(s):  
sławomir Grądziel
Keyword(s):  
Boundary Condition ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Thermal Boundary Condition ◽  
Transient Temperature ◽  
Inverse Heat Conduction ◽  
Transient Temperature Distribution ◽  
Power Boiler

Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method The following paper presents the method for solving one-dimensional inverse boundary heat conduction problems. The method is used to estimate the unknown thermal boundary condition on inner surface of a thick-walled Y-branch. Solution is based on measured temperature transients at two points inside the element's wall thickness. Y-branch is installed in a fresh steam pipeline in a power plant in Poland. Determination of an unknown boundary condition allows for the calculation of transient temperature distribution in the whole element. Next, stresses caused by non-uniform transient temperature distribution and by steam pressure inside a Y-branch are calculated using the finite element method. The proposed algorithm can be used for thermal-strength state monitoring in similar elements, when it is not possible to determine a 3-D thermal boundary condition. The calculated temperature and stress transients can be used for the calculation of element durability. More accurate temperature and stress monitoring will contribute to a substantial decrease of maximal stresses that occur during transient start-up and shut-down processes.

scholarly journals The Influence of Thermal Residual Stresses on Mechanical Properties of Silicon Nitride-Based Composites

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1092
Author(s):  
Aleksandra Dubiel ◽  
Grzegorz Grabowski ◽  
Marcin Goły ◽  
Stanisław Skrzypek
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Phase Composition ◽  
Silicon Nitride ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Thermal Residual Stresses ◽  
Microstructure Parameters ◽  
Xrd Method

In this work, two kinds of silicon nitride-based composites, namely, those with titanium nitride or silicon carbide additives, were sintered using the hot pressing technique (HP). The phase composition, microstructure, and mechanical and elastic properties of the materials were characterized. Three-dimensional geometric models of the composites were created on the basis of microstructure parameters. Using these models, bulk residual thermal stresses were calculated by the finite element method (FEM). Surface stresses were determined using the XRD method of sin2ψ.

Transient Thermal Stresses on a Finite Disk Due to a Continuous Point Heat Source

1970 ◽  
Vol 92 (2) ◽  
pp. 357-365 ◽  
Author(s):  
T. R. Hsu
Keyword(s):  
Heat Source ◽  
Thermal Stresses ◽  
Circular Disk ◽  
Transient Temperature ◽  
Point Heat Source ◽  
Finite Radius ◽  
Transient Temperature Distribution ◽  
Instantaneous Point ◽  
Continuous Point ◽  
Transient Thermal

This paper contains exact solutions for the transient temperature distribution and the associated quasi-static thermal stresses and deformations which arise in a thin circular disk of finite radius subjected to a continuous point heat source acting on its periphery. It has been proven in this paper that the solutions of this type of problem may be obtained by integrating the time variable of the corresponding solutions in the case of an instantaneous point heat source. The solutions are given in the form of double infinite series and graphical representations of the solutions in dimensionless terms are included. Reference is made to methods of applying the solutions to shapes other than disks. The solutions are pertinent to problems which occur in welding engineering and modern nuclear technology.

Simulation and Experimental Study on Temperature Fields for Laser Assisted Machining of Silicon Nitride

2009 ◽  
Vol 419-420 ◽  
pp. 521-524
Author(s):  
Xue Feng Wu ◽  
Hong Zhi Zhang ◽  
Yang Wang ◽  
Chao Xie
Keyword(s):  
Silicon Nitride ◽  
Laser Heating ◽  
Laser Power ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Model ◽  
Beam Diameter ◽  
Power Laser ◽  
Laser Assisted Machining ◽  
Translational Speed

Laser assisted machining (LAM) is an effective method machining difficult-to-machine materials such as ceramics which uses a high power laser to focally heat a workpiece prior to material removal with a traditional cutting tool. A laser assisted machining experiment system was set up and a transient, three-dimensional heat transfer model was developed for LAM of silicon nitride using Finite Element Method to understand the thermal process of laser heating. The model was based on temperature-dependent thermophysical properties and the heat generated was neglected due to cutting which is assumed to be small compared to the heat generated by laser heating. The experiments were carried out to investigate the effects of operating parameters, such as laser power, laser translational speed, rotational speed, laser beam diameter and preheating time on temperature distribution. An infrared radiation thermometer was used to measure the surface temperature histories and the experimental results were in good agreement with predictions. The laser power and laser translational speed have the greatest influence on the temperature.

An Efficient 2-D Finite Element Procedure for Isothermal Phase Changes

1990 ◽  
Vol 112 (4) ◽  
pp. 352-360 ◽  
Author(s):  
S. Chandrasekar ◽  
S. Wang ◽  
H. T. Y. Yang
Keyword(s):  
Finite Element ◽  
Phase Transformation ◽  
Material Properties ◽  
Thermal Stresses ◽  
Phase Changes ◽  
Transient Temperature ◽  
Two Dimensional ◽  
Transient Temperature Distribution ◽  
Finite Element Procedure ◽  
Transformation Problems

An efficient finite element procedure is developed for the temperature and stress analyses of two-dimensional isothermal phase transformation problems such as solidification, melting, and solid-to-solid transformations, etc. This procedure uses adaptive remeshing along the element boundaries to track the discontinuities in the temperature gradient, the enthalpy, and the material properties, which exists across the phase transformation interface. The thermal stresses and the transient temperature distribution developed during solidification are calculated using this for several example problems. They are compared with the numerical and analytical solutions obtained for these problems by earlier investigators in order to demonstrate the efficiency and accuracy of this method, for the analysis of solidification problems, as well as its limitations.

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