Effect of the loading cycle asymmetry on the cyclic cracking resistance characteristics of heat-resisting steels

1987 ◽  
Vol 19 (11) ◽  
pp. 1473-1478 ◽  
Author(s):  
V. V. Pokrovskii ◽  
V. G. Kaplunenko ◽  
Yu. I. Zvezdin ◽  
B. T. Timofeev
Keyword(s):  
Cracking Resistance ◽  
Cycle Asymmetry ◽  
Loading Cycle

Effect of loading-cycle asymmetry on the crack resistance of structural alloys

1982 ◽  
Vol 14 (11) ◽  
pp. 1456-1461
Author(s):  
P. V. Yasnii ◽  
V. V. Pokrovskii ◽  
V. T. Kaplunenko ◽  
M. V. Avanesov ◽  
B. T. Timofeev ◽  
...  
Keyword(s):  
Crack Resistance ◽  
Cycle Asymmetry ◽  
Loading Cycle

Effect of loading cycle asymmetry, stress concentration, and fretting corrosion on the fatigue resistance of alloy D16T

1990 ◽  
Vol 22 (5) ◽  
pp. 678-684
Author(s):  
V. I. Dragan ◽  
S. M. Semenyuk ◽  
E. I. Mitchenko ◽  
V. O. Merkulov
Keyword(s):  
Stress Concentration ◽  
Fatigue Resistance ◽  
Fretting Corrosion ◽  
Cycle Asymmetry ◽  
Alloy D16t ◽  
Loading Cycle

Influence of crack closure and loading cycle asymmetry on kinetic fatigue failure curves at normal and low temperatures

1987 ◽  
Vol 23 (3) ◽  
pp. 285-289
Author(s):  
O. P. Ostash ◽  
V. T. Zhmur-Klimenko ◽  
E. M. Kostyk ◽  
A. B. Kunovskii
Keyword(s):  
Crack Closure ◽  
Fatigue Failure ◽  
Low Temperatures ◽  
Cycle Asymmetry ◽  
Loading Cycle

Influence of temperature and loading cycle asymmetry on the crack resistance characteristics of heat-resistant steels

1983 ◽  
Vol 15 (8) ◽  
pp. 1035-1046
Author(s):  
V. T. Troshchenko ◽  
V. V. Pokrovskii ◽  
P. V. Yasnii ◽  
Yu. S. Skorenko ◽  
M. Klesnil ◽  
...  
Keyword(s):  
Crack Resistance ◽  
Cycle Asymmetry ◽  
Influence Of Temperature ◽  
Loading Cycle ◽  
Heat Resistant ◽  
Heat Resistant Steels

Features of the kinetics of cyclic elastoplastic deformation diagrams at dwells in cycles and superimposition of variable stresses on them

2020 ◽  
Vol 86 (12) ◽  
pp. 46-53
Author(s):  
M. M. Gadenin
Keyword(s):  
Experimental Data ◽  
Elastoplastic Deformation ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Loading Cycle ◽  
Additional Variable ◽  
Dynamic Creep ◽  
Variable Stresses ◽  
Kinetics Of ◽  
Deformation Diagrams

The goal of the study is determination of the regularities of changes in cyclic strains and related deformation diagrams attributed to the existence of time dwells in the loading modes and imposition of additional variable stresses on them. Analysis of the obtained experimental data on the kinetics of cyclic elastoplastic deformation diagrams and their parameters revealed that in contrast to regular cyclic loading (equal in stresses), additional deformations of static and dynamic creep are developed. The results of the studys are especially relevant for assessing the cyclic strength of unique extremely loaded objects of technology, including nuclear power equipment, units of aviation and space systems, etc. The experiments were carried out on the samples of austenitic stainless steel under low-cycle loading and high temperatures of testing. Static and dynamic creep deformations arising under those loading conditions promote an increase in the range of cyclic plastic strain in each loading cycle and also stimulate an increase in the range of elastoplastic strain due to active cyclic deformation. At the same time the existence of dwells on extrema of stresses in cycles without imposition of additional variable stresses on them most strongly affects the growth of plastic strain ranges in cycles. Imposition of additional variable stresses on dwells also results in the development of creep strains, but their growth turns out to be somewhat less than in the presence of dwells without stresses imposed. The diagrams of cyclic deformation obtained in the experiments are approximated by power dependences, their kinetics being described in terms of the number of loading cycles using corresponding temperature-time functions. At the same time, it is shown that increase in the cyclic plastic deformation for cycles with dwells and imposition of additional variable stresses on them decreases low cycle fatigue life compared to regular loading without dwells at the same stress amplitudes, moreover, the higher the values of static and dynamic creep, the greater decrease in low-cycle fatigue life. This conclusion results from experimental data and analysis of conditions of damage accumulation for the considered forms of the loading cycle using the deformation criterion of reaching the limit state leading to fracture.

scholarly journals Effect of Intermetallic Compound Bridging on the Cracking Resistance of Sn2.3Ag Microbumps with Different UBM Structures under Thermal Cycling

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1065
Author(s):  
Chun-Chieh Mo ◽  
Dinh-Phuc Tran ◽  
Jing-Ye Juang ◽  
Chih Chen
Keyword(s):  
Electron Microscope ◽  
Intermetallic Compound ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Crack Formation ◽  
Thermal Cycling Test ◽  
Under Bump Metallization ◽  
Reflow Time ◽  
Cracking Resistance ◽  
Scanning Electron

In this study, the effect of intermetallic compound (IMC) bridging on the cracking resistance of microbumps with two different under bump metallization (UBM) systems, Cu/solder/Cu and Cu/solder/Ni, under a thermal cycling test (TCT) is investigated. The height of the Sn2.3Ag solders was ~10 µm, which resembles that of the most commonly used microbumps. We adjusted the reflow time to control the IMC bridging level. The samples with different bridging levels were tested under a TCT (−55–125 °C). After 1000 and 2000 TCT cycles (30 min/cycle), the samples were then polished and characterized using a scanning electron microscope (SEM). Before IMC bridging, various cracks in both systems were observed at the IMC/solder interfaces after the 1000-cycle tests. The cracks propagated as cyclic shapes from the sides to the center and became more severe as the thermal cycle was increased. With IMC bridging, we could not observe any further failure in all the samples even when the thermal cycle was up to 2000. We discovered that IMC bridging effectively suppressed crack formation in microbumps under TCTs.

scholarly journals Fatigue Cracking Resistance of Engineered Cementitious Composites (ECC) under Working Condition of Orthotropic Steel Bridge Decks Pavement

2019 ◽  
Vol 9 (17) ◽  
pp. 3577 ◽  
Author(s):  
Yanjing Zhao ◽  
Jiwang Jiang ◽  
Fujian Ni ◽  
Lan Zhou
Keyword(s):  
Digital Image ◽  
Working Condition ◽  
Fatigue Cracking ◽  
Surface Strain ◽  
Internal Crack ◽  
Cementitious Composites ◽  
Cracking Resistance ◽  
Engineered Cementitious Composites ◽  
Crack Distribution ◽  
Scb Test

In order to investigate the fatigue cracking resistance of engineered cementitious composites (ECC) used in in total life pavement, the semi-circular bending (SCB) test and improved three-point bending fatigue test (ITBF) were utilized in this study. The digital image correlation (DIC) method was also utilized to track the surface strain fields of specimens during the SCB test. X-ray computed tomography (CT) and digital image processing (DIP) technologies were applied to measure the internal-crack distribution of the ITBF specimen. The results of the SCB test showed that the fatigue cracking damage process of ECC can be divided into three stages and that the cracking stable propagating stages occupied the main part, which indicates that ECC has excellent ductility and toughness and could work very well with existing cracks. The ITBF results showed that the fatigue cracking resistance of ECC was better than epoxy asphalt concrete (EAC). In addition, the internal-crack distribution along the depth direction of the ITBF specimen could be presented well by the image pixel statistical (IPS) method based on CT scanning of image slices. It could be found that multiple cracks propagate simultaneously in ECC, instead of a single crack, under the OSBD pavement working condition.

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