Analytical Approach to Crack Arrest Tendency Under Cyclic Thermal Stress for an Inner-Surface Circumferential Crack in a Finite-Length Cylinder

2000 ◽  
Vol 123 (2) ◽  
pp. 220-225 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Katsuhiko Watanabe
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Finite Length ◽  
Thermal Stresses ◽  
Structural Parameters ◽  
Crack Arrest ◽  
Coolant Temperature ◽  
Transfer Condition ◽  
Circumferential Crack ◽  
Inner Surface

This paper presents a study of the crack arrest tendency under cyclic thermal stress for an inner-surface circumferential crack in a finite-length cylinder with its edges rotation-restrained, when the inside of the cylinder is cooled from uniform temperature distribution. The effects of structural parameters and heat transfer condition on the maximum transient SIF for the problem were investigated with the formerly developed systematical evaluation methods. Then, a tentative value of threshold stress intensity range ΔKth being assumed as well as Paris law, the evaluation of crack length for crack arrest under cyclic thermal stresses was carried out. Finally, a map to find the crack arrest point for a cylinder with mean radius to wall thickness ratio Rm/W=1 and a specific length H under various heat transfer conditions could be originated. From the map, it was predicted that when the heat transfer coefficient and/or initial wall-coolant temperature differences become large enough, the nondimensional crack arrest length saturates to a specific value and is no longer affected by those conditions.

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.

Modelling of Convective Melt Flow and Interface Shape in Commercial Bridgman-Stockbarger Growth of CdZnTe

2000 ◽  
Author(s):  
Toby D. Rule ◽  
Ben Q. Li ◽  
Kelvin G. Lynn
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Solute Transport ◽  
Latent Heat ◽  
Thermal Stresses ◽  
Radiation Detector ◽  
Time History ◽  
High Quality ◽  
Melt Convection ◽  
The Impact

Abstract CdZnTe single crystals for radiation detector and IR substrate applications must be of high quality and controlled purity. The growth of such crystals from a melt is very difficult due to the low thermal conductivity and high latent heat of the material, and the ease with which dislocations, twins and precipitates are introduced during crystal growth. These defects may be related to solute transport phenomena and thermal stresses associated with the solidification process. As a result, production of high quality material requires excellent thermal control during the entire growth process. A comprehensive model is being developed to account for radiation and conduction within the furnace, thermal coupling between the furnace and growth crucible, and finally the thermal stress fields within the growing crystal which result from the thermal conditions imposed on the crucible. As part of this effort, the present work examines the heat transfer and fluid flow within the crucible, using thermal boundary conditions obtained from experimental measurements. The 2-D axisymetric numerical model uses the deforming finite element method, with allowance made for melt convection, solidification with latent heat release and conjugate heat transfer between the solid material and the melt. Results are presented for several stages of growth, including a time-history of the solid-liquid interface (1365 K isotherm). The impact of melt convection, thermal end conditions and furnace temperature gradient on the growth interface is evaluated. Future work will extend the present model to include radiation exchange within the furnace, and a transient analysis for studying solute transport and thermal stress.

scholarly journals Thermal Elastic-Plastic Stress Analysis of an Aluminium Composite Disc under Linearly Decreasing Thermal Loading

2008 ◽  
Vol 17 (3) ◽  
pp. 096369350801700 ◽  
Author(s):  
Muzaffer Topcu ◽  
Gurkan Altan ◽  
Hasan Callioglu ◽  
Burcin Deda Altan
Keyword(s):  
Thermal Stress ◽  
Stress Analysis ◽  
Tangential Stress ◽  
Outer Surface ◽  
Thermal Stresses ◽  
Stress Component ◽  
Aluminium Composite ◽  
Hardening Material ◽  
Elastic Plastic ◽  
Inner Surface

In this study, an elastic-plastic thermal stress analysis of an orthotropic aluminium metal matrix composite disc with a hole has been investigated analytically for non-linear hardening material behaviour. The aluminium composite disc reinforced curvilinearly by steel fibres is produced under hydraulic press. The mechanical properties of the composite disc are obtained by tests. A computer program is developed to calculate the thermal stresses under a linearly decreasing temperature from inner surface to outer surface. Elastic, elastic-plastic and residual thermal stress distributions are obtained analytically from inner surface to outer surface and they are presented in tables and Fig. s. The elastic-plastic solution is performed for the plastic region expanding around the inner surface. The magnitude of the tangential stress component has been found out in this study to be higher than the magnitude of the radial stress component. Besides, the tangential stress component is compressive at the inner surface and tensile at the outer surface. The magnitude of the tangential residual stress component is the highest at the inner surface of the composite disc.

Thermal Stress Analysis of Nonuniformly Heated Cylindrical Shell and Its Application to a Steam Generator Membrane Wall

1968 ◽  
Vol 90 (1) ◽  
pp. 73-81 ◽  
Author(s):  
P. P. Bijlaard ◽  
R. J. Dohrmann ◽  
J. M. Duke
Keyword(s):  
Heat Transfer ◽  
Cylindrical Shell ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Steam Generator ◽  
Thermal Stresses ◽  
Material Selection ◽  
Longitudinal Axis ◽  
Flow Rates ◽  
Circuit Configuration

A method has been developed which accurately predicts the thermal stresses and deformations in a nonuniformly heated cylindrical shell and has been applied to a steam generator membrane wall. The analysis is based on the theory of thermoelasticity and treats the membrane wall as a repetitive geometry. The tube and membrane are treated separately and are later joined, satisfying continuity. The analysis is also applicable to drums, nozzles, shells, and other cylindrical vessels as long as the temperture is steady and independent of the longitudinal axis of the geometry. Through the use of this method the thermal stresses can readily be calculated and thus assist in the establishment of flow rates, heat input or flux levels, circuit configuration, and material selection. In addition it provides the information to evaluate the effects of the inside heat transfer coefficient and variations in tube and web geometries on the thermal stresses.

Three-Dimensional Surface Heat Transfer Coefficient and Thermal Stress Analysis for Ceramics Tube Dipping into Molten Metal

2010 ◽  
Vol 452-453 ◽  
pp. 233-236 ◽  
Author(s):  
Yasushi Takase ◽  
Wen Bin Li ◽  
Hendra ◽  
Hiroki Ogura ◽  
Yusuke Higashi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Molten Metal ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Surface Heat ◽  
Surface Heat Transfer ◽  
Surface Heat Transfer Coefficient

The low pressure die casting machine has been used in industries because of its low-cost and high efficiency precision forming technique. In the low pressure die casting process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal, by means of a pressurized gas, to rise into a ceramic tube, which connects the die to the furnace. The ceramics tube, called stalk, has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the ceramics tube is dipped into the molten metal. It is important to reduce the risk of fracture that may happen due to the thermal stresses. To calculate the thermal stress, it is necessary to know the surface heat transfer coefficient when the ceramics tube dips into the molten metal. In this paper, therefore, the three-dimensional thermo-fluid analysis is performed to calculate surface heat transfer coefficient correctly. The finite element method is applied to calculate the thermal stresses when the tube is dipped into the crucible with varying dipping speeds and dipping directions. It is found that the thermal stress can be reduced by dipping slowly when the tube is dipped into the molten metal.

An Inverse Method for Determining Thermal Load History Which Reduces Transient Thermal Stress

2006 ◽  
Author(s):  
Takuya Ishizaka ◽  
Shiro Kubo ◽  
Seiji Ioka
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Temperature Distribution ◽  
Thermal Load ◽  
Inverse Method ◽  
Temperature History ◽  
Load History ◽  
Transient Thermal Stress ◽  
Inner Surface ◽  
Transient Thermal

When high temperature fluid flows into a pipe, a temperature distribution in the pipe induces a thermal stress. It is important to reduce the thermal stress for managing and extending the lives of plants. In this problem heat conduction, elastic deformation, heat transfer, liquid flow should be considered, and therefore the problem is of multidisciplinary nature. In this paper an inverse method is proposed for determining the optimum thermal load history which reduces transient thermal stress considering the multidisciplinary physics. As a typical problem, transient thermal stress in a thin pipe during start-up was treated. It was assumed that the inner surface was heated by liquid flow and the outer surface was insulated for simplicity. The multidisciplinary complex problem was decomposed into a heat conduction problem with given internal wall temperature history, thermal stress problem with given temperature distribution, and heat transfer problem with given heat flux on an inner surface. An analytical solution of the temperature distribution of the radial thickness and the thermal hoop stress distribution was obtained. The maximum inner hoop tensile stress was minimized for the case where inner surface temperature Ts(t) was expressed in terms of the 3rd order polynomial function of time t. Finally, from the temperature distributions, the optimum fluid temperature history was obtained for reducing the transient thermal tensile stress.

TRANS2A: An Unconditionally Stable Code for Thermal Transient Stress Analysis in Piping

1981 ◽  
Vol 103 (1) ◽  
pp. 50-58 ◽  
Author(s):  
B. R. Strong ◽  
G. C. Slagis
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
Benchmark Problems ◽  
Solution Stability ◽  
Matrix Formulation ◽  
Difference Matrix ◽  
Water Steam ◽  
Complete Set

A technique for numerical integration of the finite difference (matrix) formulation of the unsteady heat transfer equation has been applied to the thermal stress analysis requirements of ASME B&PV Section III, Article NB-3650. This technique, with its properties of unconditional solution stability, has been incorporated into a new computer program, TRANS2A, which has been designed totally around the needs of the stress analyst. To be of maximum aid to the analyst, in addition to the necessary output of thermal gradients (ΔT2 and ΔT2) and average temperatures (Ta and Tb), TRANS2A provides a complete set of thermal stress histories and tables of thermal stress extrema. Values of the thermal stresses are output at maxima of the thermal gradient terms (with or without adjacent sections), in addition to the extrema of the secondary and secondary plus peak stresses and time of occurrence. Each solution is performed for a set of seven general and three optional stress indices. The process allows a strict and simple data interface to the combined stress analaysis computation without excessive approximations. Data may also be stored so that sections need not require repeated analyses. All computational output, from the detailed heat transfer solution to the stress summaries, may be requested or deleted at the option of the analyst. For generality, TRANS2A includes a complete set of temperature-dependent material properties for all current piping materials and a complete set of fluid properties for water, steam, and sodium. Fluid transient data are input using phase and temperature, and a choice of four flow rate specifications. Accepted heat transfer correlations for laminar and turbulent flow in liquids and gases are included, with smoothing at two-phase excursions. Samples of the TRANS2A benchmark problems are included, with discussions on data interface and sensitivity for erratic fluid transients.

Modeling of Carburization and Thermal Stress Analysis for Ethylene Cracking Furnace Tube

2011 ◽  
Vol 704-705 ◽  
pp. 1136-1140
Author(s):  
Lu Yang Geng ◽  
Jian Ming Gong ◽  
Xiao Yan Qin ◽  
Li Min Shen
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Carbon Concentration ◽  
Thermal Stresses ◽  
Longitudinal Direction ◽  
Heating Process ◽  
Finite Element Code ◽  
Furnace Tube ◽  
The Finite Difference Method ◽  
Ethylene Cracking Furnace

The ethylene cracking furnace tube is one of the most important components of an ethylene cracking furnace. Carburization of furnace tube is one of the most important causes which lead the tube to fail. In this paper, the model that describes diffusion of carbon and the precipitation of carbides was established based on Fick’ law and equilibrium constant method. The finite difference method was adopted to simulate the distribution of carbon concentration. By applying the model, the distribution of carbon concentration along thickness in HP-Nb tubes was predicted for the different service times. According to the temperature distribution of furnace tube, obtained by the analysis of heat transfer, the thermal stresses of the furnace tube with various carburization extents were analyzed by using the finite element code ABAQUS for the actual heating process of an ethylene cracking furnace. The analysis results show that the maximum circumferential thermal stress exists near the inner wall of the carburized tube, which usually causes cracking of the carburized tube along the longitudinal direction.

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