Induction of preset thermally stressed states in thermal fatigue tests: Choice of testing conditions and geometry of specimens

1997 ◽  
Vol 29 (4) ◽  
pp. 369-379
Author(s):  
G. N. Tretyachenko ◽  
B. S. Karpinos ◽  
V. G. Barilo ◽  
N. G. Solovyeva
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests ◽  
Testing Conditions ◽  
Thermally Stressed

Thermal Fatigue Characteristics of Heat-Resisting Stainless Steel for Automotive Exhaust

2007 ◽  
Vol 539-543 ◽  
pp. 4944-4949 ◽  
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung
Keyword(s):  
Thermal Fatigue ◽  
Stainless Steels ◽  
Fatigue Property ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Automotive Exhaust ◽  
Load Relaxation ◽  
Temperature Ranges ◽  
Fatigue Characteristics ◽  
Efficiency And Reliability

Thermal fatigue is a complex phenomenon encountered in materials exposed to cyclically varying temperatures in the presence or absence of external load. Continually increasing working temperature and growing need for greater efficiency and reliability of automotive exhaust require immediate investigation into the thermal fatigue properties especially of high temperature stainless steels. In this study, thermal fatigue properties of 304 and 429EM stainless steels have been evaluated in the temperature ranges of 200-800oC and 200-900oC. Systematic methods for control of temperatures within the predetermined range and measurement of load applied to specimens as a function of temperature during thermal cycles have been established. Thermal fatigue tests were conducted under fully constrained condition, where both ends of specimens were completely fixed. Thermal fatigue property of STS 304 was superior to that of STS 429EM. Load relaxation behavior at the temperatures of thermal cycle was closely related with the thermal fatigue property.

Thermal-fatigue tests of restraned combustor-cooling tubes

1967 ◽  
Vol 7 (6) ◽  
pp. 256-264 ◽  
Author(s):  
L. R. Avery ◽  
G. S. Carayanis ◽  
G. L. Michky
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests

Thermal fatigue tests with actively cooled divertor mock-ups for ITER

1998 ◽  
Vol 39-40 ◽  
pp. 551-557 ◽  
Author(s):  
M. Rödig ◽  
R. Duwe ◽  
C. Ibbott ◽  
D. Jacobson ◽  
G. Le Marois ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests

Thermal fatigue tests of a W-Cu duplex structure for a divertor application

1989 ◽  
Vol 9 ◽  
pp. 277-282 ◽  
Author(s):  
K. Kitamura ◽  
Y. Shibutani ◽  
M. Shibui ◽  
K. Nagata ◽  
T. Araki ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests ◽  
Duplex Structure

Microstructure Change of Bionic Units on Vermicular Cast Iron Processed by Laser in Thermal Fatigue Tests

2012 ◽  
Vol 562-564 ◽  
pp. 156-159
Author(s):  
Yan Liu ◽  
Hong Zhou ◽  
Chun Yan Yang ◽  
Chao Meng ◽  
Chuan Wei Wang ◽  
...  
Keyword(s):  
Cast Iron ◽  
Failure Mode ◽  
Fatigue Failure ◽  
Thermal Fatigue ◽  
Fatigue Tests ◽  
Layer By Layer ◽  
Microstructure Change

This paper focuses on the microstructure change of bionic units, processed by the bionic laser, on vermicular cast iron, during the thermal fatigue tests. The results show that the microstructure of bionic units is uneven, and the thermal fatigue first occurs in the region with coarser microstructure on the surface of bionic units; the thermal fatigue failure mode of the bionic units is oxidizing, fracturing and peeling layer by layer.

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.

Spectra Thermal Fatigue Tests Under Frequency Controlled Fluid Temperature Variation: Superposed Sinusoidal Temperature Fluctuation Tests

2008 ◽  
Author(s):  
Nobuchika Kawasaki ◽  
Hideki Takasho ◽  
Sumio Kobayashi ◽  
Shinichi Hasebe ◽  
Naoto Kasahara
Keyword(s):  
Fatigue Strength ◽  
Crack Initiation ◽  
Thermal Fatigue ◽  
Test Piece ◽  
Fatigue Tests ◽  
Fluid Temperature ◽  
Test Pieces ◽  
Temperature Waves ◽  
Temperature Ranges ◽  
Sinusoidal Temperature

To clarify frequency-dependent attenuation effects of fluid temperature fluctuation on fatigue strength, thermal fatigue strength tests subjected to superposed sinusoidal temperature fluctuations were performed by the SPECTRA test facility. Fluid temperature waves were generated by superposition of sinusoidal waves, where frequencies were 0.05, 0.2, and 0.5Hz. Two types of superposed waves were selected for the tests, dual and triple ones. The dual one was obtained by superposing two sinusoidal waves whose temperature ranges and frequencies are respectively 200 centigrade and 0.05Hz and 60 centigrade and 0.5Hz at the inlet of test piece. The triple one was the superposition of three sinusoidal waves whose temperature ranges and frequencies are respectively, 150 centigrade and 0.2Hz, 75 centigrade and 0.05Hz and 50 centigrade and 0.5Hz at the inlet of test piece. The longest periods were 20 seconds for both types of waves and it is the fundamental cycle for the thermal fatigue tests. For the dual case, 73,810 cycles fatigue test was performed while for the triple one 116,640 cycles were performed. After these fatigue tests, cylindrical test pieces were cut away from the test loop, and cracks were observed on the inner surface of the test pieces. For the dual wave case, crack initiation occurred from 400 to 600mm position from the inlet of test piece. For the triple wave case, crack initiation occurred from 400 to 600mm position from the inlet of test piece. The corresponded fluid temperature range to crack initiation is from 205 to 220 centigrade for the dual one and from 195 to 215 centigrade for the triple one. Fatigue lives at crack initiation positions were evaluated based on the test conditions. Adopting power spectrum density functions and frequency transfer functions, fatigue lives were predicted within a factor 3 as predicted for single sinusoidal temperature waves in the other tests. To confirm advantages of these functions, fatigue life estimations were compared with those obtained without using these functions. Based on the compared results, these functions are necessary to predict accurate fatigue lives.

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