An investigation into the kinetics of low-cycle fatigue strength of steel in hydrogen and vacuum

1974 ◽  
Vol 8 (3) ◽  
pp. 326-331
Author(s):  
A. N. Romaniv ◽  
Yu. V. Zima ◽  
V. I. Tkachev ◽  
R. I. Kripyakevich
Keyword(s):  
Fatigue Strength ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Kinetics Of

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.

Consideration of the cross sectional form of pipe bends when calculating their low-cycle fatigue strength

1973 ◽  
Vol 5 (10) ◽  
pp. 1287-1291 ◽  
Author(s):  
V. A. Nakhalov ◽  
R. Z. Shron ◽  
R. Kh. Baraz ◽  
R. K. Balashova
Keyword(s):  
Fatigue Strength ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Cross Sectional ◽  
The Cross

Assessment of low cycle fatigue strength of notched components

2006 ◽  
Vol 27 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Henrikas Medekshas ◽  
Valentina Balina
Keyword(s):  
Fatigue Strength ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Notched Components
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