scholarly journals Axi-Symmetrical Transient Temperature Fields and Quasi-Static Thermal Stresses Initiated by a Laser Pulse in a Homogeneous Massive Body

10.5772/23652 ◽  
2011 ◽  
Author(s):  
Aleksander Yevtushenko ◽  
Kazimierz Rozniakowski ◽  
Malgorzata Rozniakowska-Klosinsk
Keyword(s):  
Laser Pulse ◽  
Thermal Stresses ◽  
Temperature Fields ◽  
Transient Temperature

The Transient Temperature and Thermal Stresses on Metal Material Irradiated by Multi-Pulse Short Power

2011 ◽  
Vol 130-134 ◽  
pp. 873-878
Author(s):  
Guang Ying Xu
Keyword(s):  
Thermal Stress ◽  
Laser Pulse ◽  
Pulse Width ◽  
Thermal Stresses ◽  
Transient Temperature ◽  
Fourier Law ◽  
Pulse Laser Irradiation ◽  
Metal Material ◽  
Laser Pulse Width ◽  
Thermal Stress Field

Based on the non-Fourier law and thermo-elastic theory, the non-Fourier expressions of the temperature field and the thermal stress field of metal material under multi-pulse laser irradiation were deduced. Taken stainless metal and two pulse width (ω=4ps,4fs) as an example, The effects that distributions and variations of transient temperature and thermal stress are influenced by laser pulse width are studied. The results show that the magnitude and frequency of transient temperature and thermal stress are seriously affected by the laser pulse width. More narrower the laser pulse width, faster and higher the local temperature rise; as well as the thermal stresses.

scholarly journals EFFECT OF THE TEMPORAL PROFILE OF THE FRICTION POWER ON THERMAL STRESSES DURING BRAKING

2017 ◽  
Author(s):  
A. A. Yevtushenko ◽  
M. Kuciej ◽  
K. Topczewska
Keyword(s):  
Heat Flow ◽  
Thermal Stresses ◽  
Temperature Fields ◽  
Frictional Heat ◽  
Transient Temperature ◽  
Flow Density ◽  
Temporal Profile ◽  
Friction Element ◽  
Friction Power ◽  
Brake Rotor

In this paper influence of the temporal profile of frictional heat flow density on the distributions of temperature and thermal stresses in a friction element during single braking was investigated. For this purpose a one-dimensional boundary-value heat conduction problem for a half-space body (which simulates a brake rotor) heated on the outer surface by the heat flux with different intensities was formulated and solved by means of Duhamel’s theorem. Solutions were obtained for ten temporal profiles of specific friction power, which are proportional to the intensity of frictional heat flow. Based on received transient temperature fields and Timoshenko’s model of thermal bending of a thick plate with unfixed edges, the analytical distributions of quasi-static thermal stresses in a friction element were found. Achieved solutions allow conducting numerical analysis of the distributions of temperature and thermal stresses in a brake rotor with different time profiles of the specific friction power.

Analysis and Simulation of Thermal Transients and Resultant Stresses and Strains in TAB Packaging

1993 ◽  
Vol 115 (1) ◽  
pp. 34-38 ◽  
Author(s):  
M. A. Jog ◽  
I. M. Cohen ◽  
P. S. Ayyaswamy
Keyword(s):  
Thermal Stresses ◽  
Equivalent Stress ◽  
The Body ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Transfer Coefficients ◽  
Thermal Transients ◽  
Power Cycling ◽  
Accelerated Thermal Cycling

During normal power cycling of the electronic equipment, the differing coefficients of thermal expansion result in differential elongations. Because each level of packaging is subject to mounting constraints, the differential strains result in bending and shear stresses. Repeated duty cycling can cause fatigue at joints, at interfaces between different materials, at interconnection locations, or cause delamination of composite materials. Accelerated Thermal Cycling (ATC) is done to simulate the fatigue failures that may arise because of this power cycling. The current practice is to determine ATC stresses by assuming that the temperatures of various layers are equal and constant. In this study, we have relaxed the isothermal assumption and we provide results for thermal stresses and strains in a first level package. This is accomplished by accurately determining the transient temperature fields in various layers of the package. Temperature variations for different heat transfer coefficients have also been calculated. The results indicate that realistic estimates of thermal stresses and strains are only possible with models that allow for temperature variation in the body of the package. High equivalent stress values are obtained at the chip-heat sink interface and in the bumps connecting the leads to the chip.

Residual Stresses in Strength Mismatched Welded Pipes

2017 ◽  
Author(s):  
Ali Mirzaee-Sisan ◽  
Junkan Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Structural Integrity ◽  
Welding Residual Stress ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Element Analysis ◽  
Girth Welds ◽  
Welded Pipe

It is commonly understood that residual stresses can have significant effects on structural integrity. The extent of such influence varies and is affected by material properties, manufacturing methods and thermal history. Welded components such as pipelines are subject to complex transient temperature fields and associated thermal stresses near the welded regions. These thermal stresses are often high in magnitude and could cause localized yielding around the deposited weld metal. Because of differential thermal expansion/contraction episodes, misfits are introduced into the welded regions which in turn generate residual stresses when the structure has cooled to ambient temperature. This paper is based on a recently completed Joint Industry Project (JIP) led by DNV GL. It briefly reviews published experimental and numerical studies on residual stresses and strength-mismatched girth welds in pipelines. Several Finite Element Analysis (FEA) models of a reeling simulation have been developed including mapping an initial axial residual stress (transverse to the weld) profile onto a seamless girth-welded pipe. The initial welding residual stress distribution used for mapping was measured along the circumference of the girth welds. The predicted residual stresses after reeling simulation was subsequently compared with experimental measurements.

A Method of Analysis of Transient Thermal Stresses in Thermorheologically Simple Viscoelastic Solids

1964 ◽  
Vol 31 (1) ◽  
pp. 47-53 ◽  
Author(s):  
K. C. Valanis ◽  
George Lianis
Keyword(s):  
Thermal Stresses ◽  
Perturbation Technique ◽  
Sufficient Conditions ◽  
Solid Sphere ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Temperature Dependent ◽  
Viscoelastic Solids ◽  
Temperature Dependent Properties ◽  
Transient Thermal

This paper is concerned with a perturbation technique suitable for the stress analysis of viscoelastic solids with temperature-dependent properties in the presence of nonuniform transient temperature fields. The problems of the infinite slab, solid sphere, and infinitely long viscoelastic cylinder are given solutions in the form of infinite series. Sufficient conditions for the convergence of the series are established.

Experimental and Numerical Investigation of Temperature Fields in a Radial Turbine Wheel

2014 ◽  
Author(s):  
Mathias Diefenthal ◽  
Hailu Tadesse ◽  
Christian Rakut ◽  
Manfred Wirsum ◽  
Tom Heuer
Keyword(s):  
Temperature Distribution ◽  
Thermal Stresses ◽  
Commercial Vehicle ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Turbine Wheel ◽  
Numerical Investigations ◽  
Transient Temperature Distribution ◽  
Transient Temperature Field ◽  
Transient Operations

Due to increasing demands on the efficiency of modern Otto and Diesel engines, turbochargers are subjected to higher temperatures. In consequence rotor speed and temperature gradients in transient operations are more severe and therefore thermal and centrifugal stresses increase. To determine the life cycle of turbochargers more precisely, the exact knowledge of the transient temperature distribution in the turbine wheel is essential. To assess these temperature distributions, experimental and numerical investigations on a turbocharger of a commercial vehicle were performed. For this purpose, four thermocouples were applied on the shaft and the turbine wheel. The measured temperatures are used to determine the boundary conditions for the numerical calculations and to validate the results. In the numerical investigations three methods are used to determine and to analyse the transient solid body temperature distribution in respect of the fluid. The methods are compared and evaluated using the measured data. Based on the calculations the transient temperature field is discussed and conclusions concerning to the thermal stresses are drawn.

scholarly journals The use of a solution of the inverse heat conduction problem to monitor thermal stresses

2019 ◽  
Vol 108 ◽  
pp. 01003
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Karol Kaczmarski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Power Plants ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Temperature Fields ◽  
Thick Wall ◽  
Fluid Temperature ◽  
Unsteady Temperature

Thick-wall components of the thermal power unit limit maximum heating and cooling rates during start-up or shut-down of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points respectively for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fastchanging fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using FEM (Finite Element Method) based on experimentally estimated fluid temperature and heat transfer coefficient

Identification of three-dimensional transient temperature fields in thick-walled elements using the inverse method

2018 ◽  
Vol 28 (1) ◽  
pp. 138-150 ◽  
Author(s):  
Magdalena Jaremkiewicz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Inverse Method ◽  
Thermal Stresses ◽  
Computing Time ◽  
Transient Temperature ◽  
Content Type ◽  
Inner Surface ◽  
The Heat Transfer Coefficient

Purpose The purpose of this paper is to propose a method of determining the transient temperature of the inner surface of thick-walled elements. The method can be used to determine thermal stresses in pressure elements. Design/methodology/approach An inverse marching method is proposed to determine the transient temperature of the thick-walled element inner surface with high accuracy. Findings Initially, the inverse method was validated computationally. The comparison between the temperatures obtained from the solution for the direct heat conduction problem and the results obtained by means of the proposed inverse method is very satisfactory. Subsequently, the presented method was validated using experimental data. The results obtained from the inverse calculations also gave good results. Originality/value The advantage of the method is the possibility of determining the heat transfer coefficient at a point on the exposed surface based on the local temperature distribution measured on the insulated outer surface. The heat transfer coefficient determined experimentally can be used to calculate thermal stresses in elements with a complex shape. The proposed method can be used in online computer systems to monitor temperature and thermal stresses in thick-walled pressure components because the computing time is very short.

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.

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