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.

scholarly journals Thermal Stresses Due to Frictional Heating with Time-Dependent Specific Power of Friction

2017 ◽  
Vol 11 (4) ◽  
pp. 280-284 ◽  
Author(s):  
Katarzyna Topczewska
Keyword(s):  
Thermal Stresses ◽  
Frictional Heating ◽  
Subsurface Layer ◽  
Specific Power ◽  
Dimensionless Temperature ◽  
Friction Element ◽  
Friction Power ◽  
Thermal Bending ◽  
The Coefficient Of Friction ◽  
Spatio Temporal

AbstractIn this paper influence of temporal profile of the specific friction power (i.e. the product of the coefficient of friction, sliding velocity and contact pressure) on thermal stresses in a friction element during braking was investigated. Spatio-temporal distributions of thermal stresses were analytically determined for a subsurface layer of the friction element, based on the model of thermal bending of a thick plate with unfixed edges (Timoshenko and Goodier, 1970). To conduct calculations, the fields of dimensionless temperature were used. These fields were received in the article (Topczewska, 2017) as solutions to a one-dimensional boundary-value problem of heat conduction for a semi-space heated on its outer surface by fictional heat flux with three, different time profiles of the friction power.

scholarly journals SOLVING TRANSIENT INVERSE HEAT TRANSFER PROBLEMS IN COMPLEX GEOMETRIES USING PHYSICS-GUIDED NEURAL NETWORKS (PGNN)

2021 ◽  
Vol 2021 (3) ◽  
pp. 4540-4547
Author(s):  
D. Emonts ◽  
◽  
J. Yang ◽  
R. H. Schmitt ◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Input Parameter ◽  
Temperature Fields ◽  
Elastic Behavior ◽  
Transient Temperature ◽  
Complex Geometries ◽  
Inverse Heat Transfer ◽  
Geometric Inspection ◽  
Transfer Problems

Temporally and spatially unstable thermal conditions lead to transient or inhomogeneous thermo-elastic behavior of workpieces during manufacturing or geometric inspection. Temperature monitoring by means of sensors consign transient temperature fields, but do not yield information about the heat flow acting as thermal boundary condition, which is a relevant input parameter for nearly any thermal simulation. Addressing the need for efficient methods, the authors propose an approach to solve inverse heat transfer problems in complex geometries. In the presented study, locally acting heat loads are experimentally investigated based on virtual demonstrators running in FEM. The conducted method shows high potential for transient heat flow modelling in terms of accuracy and computational efficiency.

scholarly journals Numerical analysis of meshing heating of involute spur gear

2021 ◽  
Vol 2133 (1) ◽  
pp. 012033
Author(s):  
Jie Mu ◽  
Yusheng Zhai ◽  
Chengzhi Wang ◽  
Ruiguang Yun ◽  
Jianfeng En ◽  
...  
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Tangential Velocity ◽  
Frictional Heat ◽  
Tooth Surface ◽  
Flow Density ◽  
Heat Flow Density ◽  
Average Heat ◽  
Surface Meshing ◽  
Driving Wheel

Abstract Involute spur gears generate heat due to tooth surface meshing friction. Excessive temperature rising affects transmission accuracy and reduces work reliability.. By establishing the normalized coordinates of the meshing curve and based on the frictional heat generation theory, the mathematical analysis model of the meshing surface heating is studied, the factors affecting the average heat flux density of meshing are explored, and the distribution law of these factors along the normalized coordinate of the meshing is analysed. The analysis shows that the tangential velocity of the meshing point and the half-bandwidth of the time domain contact have the greatest influence on the average heat flow density; the average heat flow density distribution of the driving wheel and the driven wheel are similar. The heat flow density of the driving wheel is greater than that of the driven wheel. Tooth shape modification minimizes tooth surface meshing contact stress, reduces meshing heat generation, controls temperature rise and improves transmission reliability.

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.

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