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Vol.7 No.1previous AASP14 (87-88-89-90-91-92-93-94-95-96-97-
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Academic Articles
Regular Paper Vol.7 No.1 (2015) p.1 - p.7
 

Development and Applicability Evaluation of Frequency Response Function of Structures to Fluctuations of Thermal Stratification

 
Kohei SODA1, Masaaki SUZUKI1, Naoto KASAHARA1, Daniel CONSTANDA1, Hiroshi KURIBAYASHI1
 

1 The University of Tokyo, School of Engineering, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

 
Abstract
The oscillation of a thermal stratification layer can induce thermal fatigue damage on structures with nuclear components. To evaluate the thermal stress induced by thermal stratification oscillation, a frequency response function was developed in our previous research. However, this function does not consider the thickness of the stratified layer. Thus, it is difficult to evaluate the stress generated by actual thermal stratified layers having finite thicknesses with sufficient accuracy. To clarify the effects of layer thickness on induced thermal stress, finite element simulations were conducted under various fluid conditions. As a result, it was clarified that the non-dimensional layer thickness Ht*, which is the ratio of layer thickness to layer oscillation length, can explain the thermal stress response mechanism with layer thickness. Based on the clarified mechanisms, the frequency response function was improved. Applicability of the proposed function to a closed branch pipe of a Light Water Reactor (LWR) and the upper plenum of a pressure vessel of a Fast Breeder Reactor (FBR) was validated through comparison with finite element simulations.
 
Keywords
Thermal Stress, Thermal Fatigue, Thermal Stratification Oscillation, Frequency Response Function, Finite Element Simulation, Temperature Attenuation
 
Full Paper: PDF EJAM Vol7.No.1 pp.1-7 "Development and Applicability Evaluation of Frequency Response Function of Structures to Fluctuations of Thermal Stratification"
Article Information
Article history:
Received 20 November 2014
Accepted 24 December 2014