scholarly journals Study on the Thermal Stress Reduction Method Using Heat Controlling Agent in Massive Concrete Wall.

2000 ◽  
pp. 121-134
Author(s):  
Kunikazu AZUMA ◽  
Tetsuya HIRONAKA ◽  
Hidetaka UMEHARA
Keyword(s):  
Thermal Stress ◽  
Stress Reduction ◽  
Reduction Method ◽  
Concrete Wall ◽  
Massive Concrete

Development of Stress Reduction Method in the Pipe Welded Zone by Heating

2010 ◽  
Author(s):  
Yuka Fukuda ◽  
Shinobu Okido
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Thermal Stress ◽  
Tensile Stress ◽  
Stress Reduction ◽  
Reduction Method ◽  
Residual Tensile Stress ◽  
Low Carbon ◽  
Inner Surface ◽  
Reduction Methods

Some cases of Stress Corrosion Cracking (SCC) failures in the proximity of welded zone of core internals and pipes in Primary Loop Recirculation, which are made of austenitic stainless steel, were reported in existing boiling water reactors, from the late 1970s to 1980s. As a countermeasure against SCC, low-carbon stainless steel was developed in order to reduce susceptibility to SCC, and used as standard material at that time. However, SCC failures were still observed in the core internals and pipes made of low-carbon stainless steel in recent years. It is well understood that residual tensile stress due to welding largely affects occurrence and growth of SCC in low-carbon stainless steel. Based on these observations, stress reduction methods for the pipe welded zone have already been developed such as Induction Heating Stress Improvement (IHSI) and Heat Sink Welding (HSW). However, these stress reduction methods are applied to only large-bore, thick-wall pipes, because it is difficult to apply these established countermeasures to the small-bore, thin-wall pipes which diameter is 50A and below. Thus stress reduction method for small-bore pipe has not been established. In this study, residual tensile stress reduction method that is applicable to the welded zone of small-bore pipe has been developed. The stress reduction method uses rapid quenching of inner surface of the pipe by cooling water after heating outer surface of the pipe by a heating device. Just after starting to cool the inside of the pipe, the temperature of the inner surface is low and tensile stress is generated. On the other hand, since temperature of outer surface is high, large temperature difference between inside and outside surface of the pipe develop and the high through-wall thermal stress is generated. When the temperature difference between the inner and outer surfaces of the pipe is large, thermal stress exceeds the yield stress on the pipe inner surface, and plastic deformation occurs on the inner surface of the pipe. The residual stress of the inner surface becomes compressive after the heat treatment due to the residual layer of plastic strain. In this study, the effectiveness of this method is shown by comparing the residual stress on the inner surface of the pipe before and after the application of this method by mock-up tests.

scholarly journals IGBT Thermal Stress Reduction Using Advance Control Strategy

Procedia CIRP ◽  
2017 ◽  
Vol 59 ◽  
pp. 274-279 ◽  
Author(s):  
Payam Soulatiantork ◽  
Alireza Alghassi ◽  
Marco Faifer ◽  
Suresh Perinpanayagam
Keyword(s):  
Thermal Stress ◽  
Stress Reduction ◽  
Control Strategy

Thermal-stress reduction for a Czochralski grown single crystal

2006 ◽  
Vol 59 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Huaxiong Huang ◽  
Shuqing Liang
Keyword(s):  
Thermal Stress ◽  
Single Crystal ◽  
Stress Reduction ◽  
Grown Single Crystal

scholarly journals Impact of the disconnection of cable shields on the thermal stress reduction in case of cross-country faults

2017 ◽  
Vol 2017 (1) ◽  
pp. 1188-1192
Author(s):  
Maurizio Della Corte ◽  
Luigi D'orazio ◽  
Andrea Malerba ◽  
Federico Marmeggi
Keyword(s):  
Thermal Stress ◽  
Stress Reduction ◽  
Cross Country

Design of the Thickness of Hot Corner Protection of LNG Storage Tank

2011 ◽  
Vol 347-353 ◽  
pp. 3777-3780
Author(s):  
Xu Dong Cheng ◽  
Xing Ji Zhu ◽  
Wen Shan Peng
Keyword(s):  
Thermal Stress ◽  
Natural Gas ◽  
Thermal Protection ◽  
Pressure Vessels ◽  
Wall Structure ◽  
Concrete Wall ◽  
Theoretical Derivation ◽  
Finite Element Software ◽  
Special Cases ◽  
Liquid Natural Gas

Large LNG storage tanks as liquid natural gas cryogenic pressure vessels, the cold between the tanks and concrete wall is very important. In some special cases, ultra-low temperature liquefied natural gas will enter the second vessel, then the wall will produce thermal stress, at this time the main factor to control the temperature difference between inside and outside the wall is the hot corner protection. This paper introduces the general international structure of tank insulation, and then through the theoretical derivation, gives the insulating layer, hot corner protection and formula for calculating temperature distribution of exterior wall. On this basis, gives the formula for calculating the external thermal stress and thermal protection angle is given control of the thickness of the design equation. Finally, using ADINA finite element software to establish insulation and the wall temperature field model and calculate the heat - wall structure coupled thermal stress, and through the analysis of a project example to verify the correctness of the formula. The results show that in the leakage state, temperature stress of external wall is large, indicating that it is significant to design the thickness of hot corner protection.

scholarly journals Influence of the Saturation Ratio on Concrete Behavior under Triaxial Compressive Loading

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xuan-Dung Vu ◽  
Matthieu Briffaut ◽  
Yann Malecot ◽  
Laurent Daudeville ◽  
Bertrand Ciree
Keyword(s):  
Nuclear Power ◽  
Water Saturation ◽  
Confining Pressure ◽  
Degree Of Saturation ◽  
Triaxial Tests ◽  
Saturation Ratio ◽  
Concrete Wall ◽  
Saturation State ◽  
Massive Concrete ◽  
The Impact

When a concrete structure is subjected to an impact, the material is subjected to high triaxial compressive stresses. Furthermore, the water saturation ratio in massive concrete structures may reach nearly 100% at the core, whereas the material dries quickly on the skin. The impact response of a massive concrete wall may thus depend on the state of water saturation in the material. This paper presents some triaxial tests performed at a maximum confining pressure of 600 MPa on concrete representative of a nuclear power plant containment building. Experimental results show the concrete constitutive behavior and its dependence on the water saturation ratio. It is observed that as the degree of saturation increases, a decrease in the volumetric strains as well as in the shear strength is observed. The coupled PRM constitutive model does not accurately reproduce the response of concrete specimens observed during the test. The differences between experimental and numerical results can be explained by both the influence of the saturation state of concrete and the effect of deviatoric stresses, which are not accurately taken into account. The PRM model was modified in order to improve the numerical prediction of concrete behavior under high stresses at various saturation states.

ACTIVE COOLING AND THERMAL STRESS REDUCTION IN A POROELASTIC HOLLOW SPHERE

1997 ◽  
Vol 20 (3-4) ◽  
pp. 389-405 ◽  
Author(s):  
Tsuyoshi Kodashima ◽  
Michio Kurasbige
Keyword(s):  
Thermal Stress ◽  
Stress Reduction ◽  
Hollow Sphere ◽  
Active Cooling
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