The retardation effect of static torsion on fatigue crack growth in strip steel

2020 ◽  
Vol 43 (8) ◽  
pp. 1800-1813
Author(s):  
Yun‐chao Lu ◽  
Te Chen ◽  
Feng‐peng Yang ◽  
Tian Lan
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Retardation Effect ◽  
Strip Steel ◽  
Static Torsion

Experimental and Analytical Studies on the Effect of Excessive Loading on Fatigue Crack Propagation in Piping Materials

2009 ◽  
Author(s):  
Yoshihito Yamaguchi ◽  
Jinya Katsuyama ◽  
Kunio Onizawa ◽  
Hideharu Sugino ◽  
Yinsheng Li ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Large Scale ◽  
Fatigue Cracks ◽  
Plastic Region ◽  
Retardation Effect ◽  
Seismic Motion ◽  
Loading Patterns ◽  
Piping Systems

The seismic regulatory guide was revised in September 2006 and the Niigata-ken Chuetsu-oki earthquake, whose magnitude was beyond the design base seismic motion, occurred in July 2007. Due to these events, attention is being drawn to the evaluation of the effects of large scale earthquakes for some piping systems in which SCC and/or fatigue cracks may potentially occur. Many papers have been already published about the retardation effect that excessive loading has on fatigue crack growth. The retardation effect is treated qualitatively in regard to the plastic strain generated by excessive loading. In this work, crack growth after excessive loading is evaluated for carbon steel and austenitic stainless steel. Some cyclic excessive loading patterns such as stepwise increases or decreases were applied to fatigue crack growth experiments. The FEM analyses were conducted to evaluate the plastic region size during these loading conditions. PFM analyses were performed to evaluate the extent to which the retardation of crack growth influences the probability of failure.

scholarly journals Effect of Underload Cycles on Oxide-Induced Crack Closure Development in Cr-Mo Low-Alloy Steel

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2530
Author(s):  
Pavel Pokorný ◽  
Tomáš Vojtek ◽  
Michal Jambor ◽  
Luboš Náhlík ◽  
Pavel Hutař
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Closure ◽  
Retardation Effect ◽  
Crack Open ◽  
Small Load ◽  
Closure Level ◽  
Oxide Debris

Underload cycles with small load amplitudes below the fatigue crack growth threshold are dominantly considered as insignificant cycles without any influence on fatigue lifespan of engineering structural components. However, this paper shows that in some cases these underload cycles can retard the consequent crack propagation quite significantly. This phenomenon is a consequence of oxide-induced crack closure development during cyclic loading below the threshold. The experimentally described effect of fatigue crack growth retardation was supported by measurement of the width and the thickness of the oxide debris layer using the EDS technique and localized FIB cuts, respectively. Both the retardation effect and the amount of oxide debris were larger for higher number and larger amplitudes of the applied underload cycles. Crack closure measurement revealed a gradual increase of the closure level during underload cycling. Specimens tested in low air humidity, as well as specimens left with the crack open for the same time as that needed for application of the underload cycles, revealed no retardation effect. The results can improve our understanding of environmental effects on fatigue crack propagation and understanding the differences between the results of laboratory testing and the fatigue lives of components in service.

Fatigue Crack Growth Retardation in Titanium Alloy

2017 ◽  
Author(s):  
Sachin Biradar ◽  
Jyoti Shankar Jha ◽  
Sushil Mishra ◽  
Asim Tewari
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Growth Retardation ◽  
Retardation Effect ◽  
Number Of Cycles ◽  
Crack Growth Retardation

The gas turbine components undergo fatigue load spectrum of variable amplitude loading. In this study, fatigue crack growth rate after multiple cycles of tensile overload has been investigated in Ti-2.77Sn-0.48Cu-1.15Fe-6.61V alloy. The overload at the crack tip produces the plastic zone at the vicinity, which retards the crack growth. Crack growth retardation effect has been studied at 15% and 25% overload percentages to observe its retardation effect. The multiple overloads applied after fixed interval of cycles produces a plastic region around the crack. After reloading the specimen further with constant loading, the crack growth rate is retarded thus causing increase in the fatigue life, which is observed in the graph of crack length vs number of cycles. The microstructure study has been carried out using Scanning Electron Microscope (SEM) and Electron Back Scatter Diffraction (EBSD), which gives qualitative information of strain to characterize the fatigue crack growth. The slope of crack length vs number of cycles before and after tensile peak overload was compared to evaluate the retardation effect at varying overload percentages.

Investigation on Evaluation Method Based on J Integral for Retardation of Crack Growth Due to Excessive Loading Beyond Small Scale Yielding Condition

2010 ◽  
Author(s):  
Yoshihito Yamaguchi ◽  
Jinya Katsuyama ◽  
Kunio Onizawa ◽  
Hideharu Sugino ◽  
Yinsheng Li
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Evaluation Method ◽  
Plastic Zone Size ◽  
Retardation Effect ◽  
Small Scale ◽  
J Integral ◽  
Small Scale Yielding ◽  
Scale Yielding

Niigata-ken Chuetsu-Oki earthquake occurred in July 2007, whose magnitude was beyond the assumed one provided in seismic design. Therefore it becomes an important issue to evaluate the effect of excessive loading, in particular, for the components with existing crack. Fatigue crack growth rate is usually expressed by Paris’s law using the range of stress intensity factor (ΔK). However, applicability of the model to loading conditions beyond the small scale yielding remains as an issue since ΔK is inappropriate in such a high loading level. In this study, the fatigue crack growth behaviors after applying the excessive loads were investigated using austenitic stainless steel and carbon steel. Instead of ΔK, J-integral value for crack growth evaluation due to cyclic loading has been applied based on the experimental data to treat the excessive loading beyond small scale yielding. The finite element method (FEM) analyses were conducted to evaluate the stress distribution and plastic zone size for the excessive loading condition. The modified Wheeler model using J-integral range, ΔJ, has been proposed for the prediction of retardation effect on crack growth after excessive loading. It was indicated that retardation effect by excessive loading beyond small-scale yielding could be quantitatively evaluated using the J-Wheeler model.

scholarly journals Numerical Modeling of Plasticity-Induced Fatigue Crack Growth Retardation Due to Deflection in the Near-Tip Area

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 541
Author(s):  
Jesús Toribio ◽  
Juan-Carlos Matos ◽  
Beatriz González
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Retardation Effect ◽  
Fatigue Crack Propagation Rate ◽  
Kinked Crack ◽  
Number Of Cycles

This article studies the retardation effect in plasticity-induced fatigue crack growth rate for a low-medium strength steel, due to the appearance of microdeflections in the crack path. To this end, the finite element method was used to model the crack with its kinked tip under several stress intensity factor (SIF) ranges. The results allowed a calculation (after a small number of cycles) of the fatigue crack propagation rate for the multiaxial and uniaxial fatigue configurations at the microscopic level. It was observed that the retardation effect rose with an increase in the initial kinked crack tip angle, an increase in the initial projected kinked crack tip length, and with a decrease in the SIF range.

A discrete dislocation analysis of fatigue crack growth

2001 ◽  
Vol 11 (PR5) ◽  
pp. Pr5-69-Pr5-75
Author(s):  
V. S. Deshpande ◽  
H. H.M. Cleveringa ◽  
E. Van der Giessen ◽  
A. Needleman
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Discrete Dislocation
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