Growth Behavior and Crack Distribution Characteristics of Small Surface Cracks of Age-Hardened Al-Alloy 2017-T4.

1996 ◽  
Vol 45 (6) ◽  
pp. 675-679
Author(s):  
Masahiro GOTO ◽  
Norio KAWAGOISHI
Keyword(s):  
Growth Behavior ◽  
Al Alloy ◽  
Distribution Characteristics ◽  
Surface Cracks ◽  
Small Surface ◽  
Crack Distribution

scholarly journals Growth behavior of small surface cracks in coarse and ultrafine grained copper

2009 ◽  
Author(s):  
M. Goto ◽  
S. Z. Han ◽  
Y. Ando ◽  
N. Kawagoishi ◽  
N. Teshima ◽  
...  
Keyword(s):  
Growth Behavior ◽  
Surface Cracks ◽  
Small Surface ◽  
Ultrafine Grained

A study on observation and growth behavior of small surface cracks by remote measurement system

KSME Journal ◽  
1996 ◽  
Vol 10 (4) ◽  
pp. 396-404 ◽  
Author(s):  
Seung Hoon Nahm ◽  
Hae Moo Lee ◽  
Chang Min Suh
Keyword(s):  
Measurement System ◽  
Growth Behavior ◽  
Remote Measurement ◽  
Surface Cracks ◽  
Small Surface

Investigation of surface fatigue microcrack growth behavior of cast Mg–Al alloy

2004 ◽  
Vol 364 (1-2) ◽  
pp. 11-16 ◽  
Author(s):  
Xi-Shu Wang ◽  
Xiao Lu ◽  
Dong-Hui Wang
Keyword(s):  
Growth Behavior ◽  
Al Alloy ◽  
Surface Fatigue ◽  
Microcrack Growth

scholarly journals Influence of Pre-Stress Magnitude on Fatigue Crack Growth Behavior of Al-Alloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1267
Author(s):  
Chunguo Zhang ◽  
Weizhen Song ◽  
Qitao Wang ◽  
Wen Liu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Shot Peening ◽  
Fatigue Property ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Al Alloy ◽  
Fatigue Crack Growth Behavior

From tensile overload to shot peening, there have been many attempts to extend the fatigue properties of metals. A key challenge with the cold work processes is that it is hard to avoid generation of harmful effects (e.g., the increase of surface roughness caused by shot peening). Pre-stress has a positive effect on improving the fatigue property of metals, and it is expected to strength Al-alloy without introducing adverse factors. Four pre-stresses ranged from 120 to 183 MPa were incorporated in four cracked extended-compact tension specimens by application of different load based on the measured stress–strain curve. Fatigue crack growth behavior and fractured characteristic of the pre-stressed specimens were investigated systematically and were compared with those of an as-received specimen. The results show that the pre-stress ranged from 120 to 183 MPa significantly improved the fatigue resistance of Al-alloy by comparison with that of the as-received specimen. With increasing pre-stress, the fatigue life first increases, then decrease, and the specimen with pre-stress of 158 MPa has the longest fatigue life. For the manner of pre-stress, no adverse factor was observed for increasing fatigue property, and the induced pre-stress reduced gradually till to disappear during subsequent fatigue cycling.

EXPERIMENTAL STUDY ON UNSATURATED DOUBLE-POROSITY SOIL PHENOMENA UNDER VIBRATION EFFECT

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Loke Kok Foong ◽  
Norhan Abd Rahman ◽  
Ramli Nazir
Keyword(s):  
Water Content ◽  
Soil Sample ◽  
Soil Structure ◽  
Double Porosity ◽  
Dominant Factor ◽  
Response Analysis ◽  
Surface Cracks ◽  
Ground Acceleration ◽  
Small Surface ◽  
Vibration Effect

A physical experiment approach was conducted to observe the deformation of double-porosity soil under vibration effect. The double-porosity soil characteristic was created using kaolin soil. An experiment on a soil sample fitted with accelerometer was conducted on a vibratory table to obtain peak ground acceleration and peak surface acceleration. After the vibration process, the deformable double-porosity soil was verified through field emission scanning electron microscopy tests. As seen in the microscope images, large surface cracks were observed due to the weakness of aggregated kaolin soil structure with its 25% water content. However, the 30% water content soil had small surface cracks due to its stronger soil structure. It was found that the deformable double-porosity soil had more fractured pores compared to the intact soil sample. From the acceleration response analysis, it was seen that both samples had amplification and dis-amplification shaking. In conclusion, the fractured double-porosity, as expected, has high permeability become a dominant factor in fluid migration. Meanwhile, the unconstrained soil and large fracture structure fabric showed significantly different porosity. The percentage of water content plays an important role in the structure of fractured double-porosity soil. 

scholarly journals Crack Growth Behavior in a Residual Stress Field for Vessel Type Structures

2003 ◽  
Author(s):  
P. Dong ◽  
G. Rawls
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Crack Growth ◽  
Surface Crack ◽  
Growth Behavior ◽  
Welding Parameters ◽  
Crack Growth Behavior ◽  
Butt Weld ◽  
Small Surface ◽  
Longitudinal Residual Stress

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.

scholarly journals Crack Growth Behavior of Al Alloy 7075-T6 under Ultrasonic Fatigue

2008 ◽  
Vol 2 (11) ◽  
pp. 1399-1409 ◽  
Author(s):  
Qiang CHEN ◽  
Norio KAWAGOISHI ◽  
Masahiro OKI ◽  
Masahiro GOTO ◽  
Qingyuan WANG
Keyword(s):  
Crack Growth ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Al Alloy ◽  
Ultrasonic Fatigue

107 Crack Growth Behavior of Al Alloy under Ultrasonic Fatigue

2005 ◽  
Vol 2005 (0) ◽  
pp. 13-14
Author(s):  
Norio KAWAGOISHI ◽  
Masahiro OKI ◽  
Masahiro GOTO ◽  
Qiang Chen ◽  
Qingyuan WANG
Keyword(s):  
Crack Growth ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Al Alloy ◽  
Ultrasonic Fatigue
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