Investigation of Thermal Fatigue Evaluation Method for Cast Iron

2013 ◽  
Author(s):  
Yutaka Sasaki ◽  
Noriaki Katori
Keyword(s):  
Cast Iron ◽  
Thermal Fatigue ◽  
Evaluation Method ◽  
Fatigue Evaluation

Thermal Fatigue Evaluation Method of Pipes by Equivalent Stress Amplitude

2012 ◽  
Author(s):  
Takafumi Suzuki ◽  
Naoto Kasahara
Keyword(s):  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Evaluation Method ◽  
Stress Amplitude ◽  
Equivalent Stress ◽  
Safety Margin ◽  
Evaluation Procedure ◽  
Fatigue Evaluation ◽  
High Cycle Thermal Fatigue ◽  
Equivalent Stress Amplitude

In recent years, reports have increased which are about failure cases caused by high cycle thermal fatigue both at light water reactors and fast breeder reactors. One of the biggest reasons of the cases is a turbulent mixing at a Tee-junction, where hot and cold temperature fluids are mixed, in a coolant system. In order to prevent thermal fatigue failures at Tee-junctions, The Japan Society of Mechanical Engineers (JSME) published the guideline S017-2003 (or JSME guideline) which is an evaluation method of high cycle thermal fatigue damage at a nuclear piping. It has some limitations in terms of its inconstant safety margin and its complexity in evaluation procedure, however. In order to solve these limitations, this paper proposes a new evaluation method of thermal fatigue damage with use of the “equivalent stress amplitude” which represents random temperature fluctuation effects on thermal fatigue damage. Because this new method makes methodology of evaluation clear and concise, it will contribute to improving the guideline for thermal fatigue evaluation.

Thermal Fatigue Evaluation Model of a Microelectronic Chip in Terms of Interfacial Singularity

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Xiaoguang Huang ◽  
Zhiqiang Wang
Keyword(s):  
Thermal Fatigue ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Thermomechanical Properties ◽  
Fatigue Tests ◽  
Strain Intensity ◽  
Intensity Factors ◽  
Singular Stress ◽  
Stress Strain ◽  
Fatigue Evaluation

Abstract Thermal fatigue failure of microelectronic chip often initiates from the interface between solder and substrate, and the service life of the chip is largely dependent on the singular stress–strain at this interface. To provide a reasonable life evaluation method, three thermal fatigue evaluation models, including strain-based and stress–strain based, have been established in terms of the interfacial singular fields. Thermal fatigue lives of different chips under different thermal cycles are obtained by thermal fatigue tests, and the stress and strain intensity factors and singular orders at the solder/substrate interface are computed at the same conditions, to determine the material constants in the established models. The thermal fatigue lives predicted are in acceptable agreement with the experimental results. What is more, the application of these thermal fatigue models demonstrates a fact that the thermal fatigue of the microelectronic chips can be evaluated uniformly no matter what the shapes, dimensions of the chip, and the thermomechanical properties of the solders are, as long as the relevant stress–strain intensity factors and singular orders are obtained.

scholarly journals Research on Strength Test Technology and Fatigue Evaluation Method of Bogie Frame and Body Bolster

2021 ◽  
Vol 1972 (1) ◽  
pp. 012038
Author(s):  
Cao Yu ◽  
Lu Chong ◽  
Li Zihua ◽  
Song Jie ◽  
Ding Xiebin
Keyword(s):  
Evaluation Method ◽  
Strength Test ◽  
Bogie Frame ◽  
Test Technology ◽  
Fatigue Evaluation

Development of 2012 Edition of JSME Code for Design and Construction of Fast Reactors: (4) Creep–Fatigue Evaluation Method for Modified 9Cr–1Mo Steel

2013 ◽  
Author(s):  
Shigeru Takaya ◽  
Yuji Nagae ◽  
Tai Asayama
Keyword(s):  
Evaluation Method ◽  
Time To Failure ◽  
Test Results ◽  
Fast Reactors ◽  
Material Test ◽  
Creep Fatigue ◽  
Summation Rule ◽  
Fatigue Evaluation ◽  
Failure Life ◽  
Design And Construction

This paper describes a creep–fatigue evaluation method for modified 9Cr–1Mo steel, which has been newly included in the 2012 edition of the JSME code for design and construction of fast reactors. In this method, creep and fatigue damages are evaluated on the basis of Miner’s rule and the time fraction rule, respectively, and the linear summation rule is employed as the failure criterion. Investigations using material test results are conducted, which show that the time fraction approach can conservatively predict failure life if margins on the initial stress of relaxation and the stress relaxation rate are embedded. In addition, the conservatism of prediction tends to increase with time to failure. Comparison with the modified ductility exhaustion method, which is known to have good failure life predictability in material test results, shows that the time fraction approach predicts failure lives to be shorter in long-term strain hold conditions, where material test data is hardly obtained. These results confirm that the creep–fatigue evaluation method in the code has implicit conservatism.

scholarly journals Muscle fatigue evaluation method of driver at long time driving based on blood lactate level increase

2020 ◽  
Vol 86 (889) ◽  
pp. 19-00433-19-00433
Author(s):  
Takumi YAMAKAWA ◽  
Soichiro HAYAKAWA ◽  
Katsuhiro ASANO ◽  
Shigeyoshi TSUTSUMI ◽  
Ryojun IKEURA
Keyword(s):  
Muscle Fatigue ◽  
Blood Lactate ◽  
Lactate Level ◽  
Evaluation Method ◽  
Blood Lactate Level ◽  
Level Increase ◽  
Long Time ◽  
Fatigue Evaluation
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