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.

Transient Thermal Stresses in a Circular Cylinder

1961 ◽  
Vol 28 (1) ◽  
pp. 25-34 ◽  
Author(s):  
C. K. Youngdahl ◽  
Eli Sternberg
Keyword(s):  
Exact Solution ◽  
Temperature Distribution ◽  
Cross Sections ◽  
Thermal Stresses ◽  
Transient Temperature ◽  
Definite Integrals ◽  
Transient Temperature Distribution ◽  
Transient Thermal ◽  
Finite Band ◽  
Uniform Change

This paper contains an exact solution for the transient temperature distribution, as well as for the accompanying quasi-static thermal stresses and deformations, which arise in an infinitely long elastic circular shaft if its surface temperature undergoes a sudden uniform change over a finite band between two cross sections and is steadily maintained thereafter. The solution given is in the form of definite integrals and infinite series, whose convergence is discussed. Extensive illustrative numerical results are included.

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.

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.

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.

scholarly journals Mathematical Model of Transient Temperature Distribution and Thermal Stresses in Large Steam Turbine Rotors

1982 ◽  
Author(s):  
J. Sasiadek ◽  
C. K. Kwok
Keyword(s):  
Mathematical Model ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Thermal Stresses ◽  
Transient Temperature ◽  
Load Variation ◽  
Transient Temperature Distribution ◽  
Start Up ◽  
On Line ◽  
Turbine Rotors

The most important problems encountered in power plants are related to cold start-up, hot start-up, daily and seasonal variation in load. These problems are specially critical for high power units above 525°C and 10.5 MN/m2. As a result of higher thermal capacity of the thicker components in larger power units, the temperature gradient and thermal stresses assumed much higher values. It is, therefore, particularly important during transient operation conditions to know the temperature distribution and thermal stresses of rotors. One of the most common concerns is how fast can a turbine be started without significant damage. If the turbine is loaded very rapidly, high temperature gradient and excessive thermal stresses can easily damage the machine. A concept was developed whereby an on-line computer was used to control the start-up and load variation operations of the turbine. The feasibility of such concept depends upon the knowledge of the instantaneous temperature distribution and thermal stresses of the turbine rotors. This paper presents a 2-D mathematical model of the transient temperature distribution as well as thermal stresses of the rotor. The mathematical model was simulated in the computer and ADI method was used for the solution of the governing equations. Discussions will be made of the procedure of coupling this mathematical model with on-line computer for optimum control of start-up and load variation schedule.

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