The Effect of Material Heterogeneity and Random Loading on the Mechanics of Fatigue Crack Growth

1986 ◽  
Vol 108 (3) ◽  
pp. 268-275
Author(s):  
T. S. Srivatsan ◽  
M. Sambandham ◽  
A. T. Bharucha-Reid
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Material Constant ◽  
Random Variable ◽  
Present Theory ◽  
Nickel Steel ◽  
Random Loading

This paper reviews the experimental work on the influence of variable amplitude or random loads on the mechanics and micromechanisms of fatigue crack growth. Implications are discussed in terms of the crack driving force, local plasticity, crack closure, crack blunting, and microstructure. Due to heterogeneity in the material’s microstructure, the crack growth rate varies with crack tip position. Using the weakest link theory, an expression for crack growth rate is obtained as the expectation of a random variable. This expression is used to predict the crack growth rates for aluminum alloys, a titanium alloy, and a nickel steel in the midrange region. It is observed using the present theory that the crack growth rate obeys the power law for small ΔK and that the power is a function of a material constant.

scholarly journals Estimation of Fatigue Crack Growth Rate for 7% Nickel Steel under Room and Cryogenic Temperatures Using Damage-Coupled Finite Element Analysis

Metals ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 603-627 ◽  
Author(s):  
Seul-Kee Kim ◽  
Chi-Seung Lee ◽  
Jeong-Hyeon Kim ◽  
Myung-Hyun Kim ◽  
Byeong-Jae Noh ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Growth Rate ◽  
Finite Element ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Nickel Steel ◽  
Cryogenic Temperatures ◽  
Element Analysis

scholarly journals Study on the Influence of the Gurson–Tvergaard–Needleman Damage Model on the Fatigue Crack Growth Rate

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1183
Author(s):  
Edmundo R. Sérgio ◽  
Fernando V. Antunes ◽  
Diogo M. Neto ◽  
Micael F. Borges
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Plastic Strain ◽  
Crack Growth ◽  
Damage Model ◽  
Crack Tip ◽  
Strength Parameter ◽  
Stress Intensity Factor Range

The fatigue crack growth (FCG) process is usually accessed through the stress intensity factor range, ΔK, which has some limitations. The cumulative plastic strain at the crack tip has provided results in good agreement with the experimental observations. Also, it allows understanding the crack tip phenomena leading to FCG. Plastic deformation inevitably leads to micro-porosity occurrence and damage accumulation, which can be evaluated with a damage model, such as Gurson–Tvergaard–Needleman (GTN). This study aims to access the influence of the GTN parameters, related to growth and nucleation of micro-voids, on the predicted crack growth rate. The results show the connection between the porosity values and the crack closure level. Although the effect of the porosity on the plastic strain, the predicted effect of the initial porosity on the predicted crack growth rate is small. The sensitivity analysis identified the nucleation amplitude and Tvergaard’s loss of strength parameter as the main factors, whose variation leads to larger changes in the crack growth rate.

Influence of reactor water of nominal parameters on fatigue crack growth rate in 15Kh2NMFA steel

1985 ◽  
Vol 21 (2) ◽  
pp. 130-133
Author(s):  
V. I. Pokhmurskii ◽  
A. S. Zubchenko ◽  
A. A. Popov ◽  
I. P. Gnyp ◽  
V. M. Timonin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Reactor Water ◽  
15Kh2nmfa Steel

Effect of Hardness and Tensile Mean Stress on Fatigue Crack Growth in Beryllium Copper

1969 ◽  
Vol 11 (3) ◽  
pp. 343-349 ◽  
Author(s):  
L. P. Pook
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mean Stress ◽  
Growth Data ◽  
Beryllium Copper

Some fatigue crack growth data have been obtained for age-hardened beryllium copper. The fatigue crack growth rate was found to be very dependent on the hardness and tensile mean stress. This dependence is believed to be associated with the intense residual stresses surrounding Preston-Guinier zones.

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