scholarly journals Tensile Thermal Stress Finite Element Analysis of ITER Axial Composite Insulation Break

Author(s):  
Chang-Chun YANG
Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.


2019 ◽  
Vol 7 (1) ◽  
pp. 1977-1986 ◽  
Author(s):  
Chih-Kuang Lin ◽  
Tsung-Ting Chen ◽  
An-Shin Chen ◽  
Yau-Pin Chyou ◽  
Lieh-Kwang Chiang

2010 ◽  
Vol 452-453 ◽  
pp. 389-392
Author(s):  
Fumitaka Motomura ◽  
Akihide Saimoto

An optimal condition of thermal stress cleaving was investigated by assuming the element-by-element temperature rise situation using finite element method. The obtained thermal stress cleaving condition is found to be optimal for the symmetrical cleaving of a rectangular plate.


Author(s):  
Guo Li ◽  
Jianping Zhao

As one of major components of heat exchanger, tubesheet is of paramount importance to enhance the safety of heat exchanger whether its design is reasonable. As the diversity of the heat exchangers’ operating condition, structures of tubesheets also become very special. A fixed tubesheet heat exchanger with a central pipe whose diameter is greater than other heat exchanger tubes is presented in this paper. A central hole in tubesheet will weaken the stiffness and intensity of the tubesheet and cause local stress concentration along the central hole’s edge. However, there is no design method for this kind of tubesheet with a central hole and it is unable to be calculated using various international standards available. In this paper, finite element analysis code ANSYS is used to simulate the real complex structure, real loads and boundary conditions of the tubesheet so that the design problem can be visualized. The three-dimensional finite element model of the tubesheet is built considering the influence of tube channel, partial shell and heat transfer tube bundle. The different pressure in shell-side and tube-side will cause the mechanical stress. The temperature gradient exists widely and the tubesheet, shell as well as heat transfer tubes can’t transform freely. Therefore, there may exists high thermal stress due to the high temperature difference in shell-side and tube-side. The thermal stress has great impact on the total stress distribution. So the simulation of the temperature field is very important. By means of thermal analysis coupling with structure analysis, the distribution of temperature, stress and deformation is obtained. Through evaluating the stress intensity of the tubesheet, it is found that the dangerous region is located at the edge of the tube distribution region and local stress concentration along the edge of the central hole is not obvious. The result shows that the tubesheet is appropriately designed and the design by finite element analysis method is feasible. This paper provides a solution for this kind of structure’s analysis design in engineering application.


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