Transient temperature fields and residual stress fields of metallic materials under welding

1991 ◽  
Vol 12 (6) ◽  
pp. 595-599 ◽  
Author(s):  
Yuan Fa-rong ◽  
Sun Hua-dong
Keyword(s):  
Residual Stress ◽  
Temperature Fields ◽  
Stress Fields ◽  
Transient Temperature ◽  
Metallic Materials

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.

Numerical Analysis on Cooling Process of Monocrystal Silicon Rod Manufactured with Czochralski Method

2012 ◽  
Vol 217-219 ◽  
pp. 1425-1428 ◽  
Author(s):  
Xiao Xia Liu ◽  
Li Jun He ◽  
Rui Zhou ◽  
Shao Lin Ma ◽  
Jing Mao
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Numerical Analysis ◽  
Czochralski Method ◽  
Temperature Fields ◽  
Stress Fields ◽  
Finite Element Code ◽  
Cooling Process ◽  
Thermally Induced ◽  
Thermal Stress Field

A numerical analysis was performed to investigate the temperature distribution and thermal stress field in monocrystal silicon rod in the cooling process of manufactured with Czochralski (CZ) method. The thermally-induced residual stress fields of silicon rod under different length of cool-down time conditions were obtained as well as temperature fields, respectively. All simulations were finished by using ANSYS finite element code. It showed that, maximum thermal stress was mainly appeared on rod surface, the influence of length of cool-down time on it was not remarkable, the magnitude of it was far below the critical strength of silicon throughout.

Experimental and Numerical Research on Application of MGC Material for High Temperature Turbine Nozzles

2005 ◽  
Author(s):  
Shu Fujimoto ◽  
Yoji Okita
Keyword(s):  
Gas Flow ◽  
High Strength ◽  
Temperature Fields ◽  
Stress Fields ◽  
Transient Temperature ◽  
Gas Temperature ◽  
Hot Gas ◽  
Numerical Research ◽  
Research On Application ◽  
Resistance Performance

In recent years, a material called MGC (Melt-Growth Composite) has been developed. This material has innovative characteristics such that it can maintain its high strength for up to 1700°C, with an excellent oxidization resistance performance. These characteristics are quite ideal for the gas turbine application. This paper deals with numerical and experimental study on the performance of MGC turbine nozzles conducted in 2003. Firstly the bow stacked solid nozzle has been designed by using numerical analyses under the gas flow condition at 1700°C that is the final target inlet gas temperature of the MGC turbine project (2001–2005). Secondly three MGC nozzles have been manufactured on trial and one of them has been tested in steady hot gas flow at 1500°C that is the target inlet gas temperature in 2003, temperature and stress fields have been evaluated numerically and the design of this MGC turbine nozzle has been validated for the steady gas flow at 1500°C. Furthermore another has been tested under a TRIP condition (TRIP: Emergency engine stop by fuel cutoff) from 1500°C level, transient temperature fields on the nozzle surface have been obtained and temperature and stress fields have been evaluated numerically. This stress analysis shows that quite large stress was generated in the nozzle in the TRIP test and therefore in future newly re-designed shape of MGC turbine nozzles is required.

Die Forging Process Simulation of a Connecting Rod

2011 ◽  
Vol 704-705 ◽  
pp. 302-307
Author(s):  
Lei Xu ◽  
Guang Ze Dai ◽  
Xing Ming Huang ◽  
Jing Han ◽  
Jun Wen Zhao
Keyword(s):  
Reduction Rate ◽  
Temperature Fields ◽  
Stress Fields ◽  
Connecting Rod ◽  
Preheat Temperature ◽  
Forging Process ◽  
Optimum Parameters ◽  
Die Forging ◽  
High Level ◽  
Deform 3D

Numerical simulation of connecting rod die forging processing was performed by finite element method (FEM) software Deform 3D. The changes of the temperature fields, stress fields of the billet and dies, and upper setting force-stroke curve during the die forging were obtained. The simulation results show that (1) the increase of the fillet radius of dies could effectively reduce the stress concentration so that to prevent the die crack arising at high level stress; (2) the optimum parameters of die forging process are 430°C for forging temperature, 200°C for preheat temperature of dies and 80mm/s for reduction rate by comparing both fields of the stress and temperature during different forging process..

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