The Influence of Residual Stress on Fatigue Cracking

1990 ◽  
Vol 112 (3) ◽  
pp. 199-203 ◽  
Author(s):  
A. Okamoto ◽  
H. Nakamura

The influence of residual stress on fatigue crack growth was experimentally and analytically investigated for surface cracks. Fatigue tests were performed on straight pipes of low-carbon steel with a circumferential inner surface crack in laboratory air environment. Some of the test pipes had been subjected to special heat treatments so as to have compressive or tensile residual stresses along inner surface. The results show that the compressive residual stress remarkably suppresses the surface crack growth, while the tensile residual stress does not accelerate the crack growth very much. The crack growth analyses were conducted by the application of power relationship between ΔK and da/dN. The stress intensity factors due to the nonlinear stress field were calculated by the weight function method. The analyses resulted in a confirmation of the behavior of the crack growth observed in the experiments.

1986 ◽  
Vol 94 (3) ◽  
pp. 241-247 ◽  
Author(s):  
H. Nakamura ◽  
E. Matsushima ◽  
A. Okamoto ◽  
T. Umemoto

2021 ◽  
Vol 11 (1) ◽  
pp. 329-338 ◽  
Author(s):  
E. Surojo ◽  
J. Anindito ◽  
F. Paundra ◽  
A. R. Prabowo ◽  
E. P. Budiana ◽  
...  

Abstract Underwater wet welding (UWW) is widely used in repair of offshore constructions and underwater pipelines by the shielded metal arc welding (SMAW) method. They are subjected the dynamic load due to sea water flow. In this condition, they can experience the fatigue failure. This study was aimed to determine the effect of water flow speed (0 m/s, 1 m/s, and 2 m/s) and water depth (2.5 m and 5 m) on the crack growth rate of underwater wet welded low carbon steel SS400. Underwater wet welding processes were conducted using E6013 electrode (RB26) with a diameter of 4 mm, type of negative electrode polarity and constant electric current and welding speed of 90 A and 1.5 mm/s respectively. In air welding process was also conducted for comparison. Compared to in air welded joint, underwater wet welded joints have more weld defects including porosity, incomplete penetration and irregular surface. Fatigue crack growth rate of underwater wet welded joints will decrease as water depth increases and water flow rate decreases. It is represented by Paris's constant, where specimens in air welding, 2.5 m and 5 m water depth have average Paris's constant of 8.16, 7.54 and 5.56 respectively. The increasing water depth will cause the formation of Acicular Ferrite structure which has high fatigue crack resistance. The higher the water flow rate, the higher the welding defects, thereby reducing the fatigue crack resistance.


1999 ◽  
Vol 122 (1) ◽  
pp. 141-145 ◽  
Author(s):  
M. Chiarelli ◽  
A. Lanciotti ◽  
M. Sacchi

The paper describes the results of a research programme, carried out at the Department of Aerospace Engineering of the University of Pisa, for the assessment of the influence of plasma cutting on the physical and mechanical properties of Fe510 D1, a low carbon steel widely used in carpentry. The activity started by observing that several industries rework plasma cut edges, particularly in the case of fatigue structures, in spite of the good quality of the plasma cut edges in a fully automatic process. Obviously, reworking is very expensive and time-consuming. Comparative fatigue tests demonstrated that the fatigue resistance of plasma cut specimens in Fe510 steel was fully comparable to that of milled specimens, as the consequence of the beneficial residual stresses which formed in the plasma cut edges. [S0094-4289(00)02201-5]


1992 ◽  
Vol 114 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Y. Nagase ◽  
S. Suzuki

Fatigue behavior of plain specimens of low carbon steel subjected to small tensile prestrain is investigated through rotating bending tests and the mechanism of the decrease of fatigue limit due to the prestrain is discussed. It is found that 3 percent prestraining causes the acceleration of both slip and crack initiations, and increases the growth rate of a small surface crack of less than 0.3 mm. It also decreases the fatigue limit. If prestrained material is aged, the fatigue limit increases. These effects of the small prestrain are explained based on the unpinning of locked dislocations due to the prestrain.


Author(s):  
Masana Kato ◽  
Gang Deng ◽  
Masashi Yamanaka ◽  
Ryoji Yamamoto ◽  
Noboru Ono ◽  
...  

Abstract The surface fatigue failures of the traction drive rollers are different to that of gears and bearings because of the high traction force, skew and small slip ratio. In this research, fatigue tests of traction rollers were performed in different slip ratios and skew angles. The effects of running conditions on the fatigue lives of traction drive rollers are clarified and explained based on the surface crack growth and wear situations. Although a higher slip ratio will make a lower fatigue life, the fatigue strength will increase inversley under the skew conditions, because of the differences in mechanical and tribological condition for surface crack growth and the severe surface wear, which diminishes the surface crack length. For evaluation of the effects of such as slip ratio and skew on the fatigue strength of traction rollers, a new method is put forward in which the relationship between the surface temperature index and fatigue life is used instead of S-N curve.


2019 ◽  
Vol 173 ◽  
pp. 80-85 ◽  
Author(s):  
Shohei Ueki ◽  
Takuya Matsumura ◽  
Yoji Mine ◽  
Shigekazu Morito ◽  
Kazuki Takashima

Author(s):  
P. Dong ◽  
G. Rawls

Detailed residual stress analysis was performed for a multi-pass butt weld, representing the middle butt-girth weld of a storage tank. The analysis procedures addressed welding parameters, joint detail, weld pass deposition sequence, and temperature-dependent properties. The predicted residual stresses were then considered in stress intensity factor calculations using a three-dimensional finite element alternating model (FEAM) for investigating crack growth behavior for both small elliptical surface and through-wall cracks. Two crack orientations were considered: one is parallel to the vessel girth weld and the other is perpendicular to the girth weld. Since the longitudinal (parallel to weld) and transverse (perpendicular to weld) residual stresses exhibit drastically different distributions, a different crack growth behavior is predicted. For a small surface crack parallel to the weld, the crack tends to grow more quickly at the surface along the weld rather than into the thickness. The self-equilibrating nature of the transverse residual stress distribution suggests that a through-wall crack parallel to crack cannot be fully developed solely due to residual stress actions. For a crack that is perpendicular to the weld, a small surface crack exhibit a rapid increase in K at the deepest position, suggesting that a small surface crack has the propensity to become a through-wall crack. Once the through crack is fully developed, a significant re-distribution in longitudinal residual stress can be seen. As a result, in the absence of external loads there exists a limiting crack length beyond which further crack growth is deemed unlikely.


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