scholarly journals Effects of Shot-Peening and Stress Ratio on the Fatigue Crack Propagation of AL 7475-T7351 Specimens

2018 ◽  
Vol 8 (3) ◽  
pp. 375 ◽  
Author(s):  
Natália Ferreira ◽  
Pedro Antunes ◽  
José Ferreira ◽  
José D. M. Costa ◽  
Carlos Capela
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Shot Peening ◽  
Stress Ratio

scholarly journals Effects of Shot-Peening and Stress Ratio on the Fatigue Crack Propagation of AL 7475-T7351 Specimens

2018 ◽  
Author(s):  
Natália Ferreira ◽  
Pedro Antunes ◽  
José A. M. Ferreira ◽  
José D. M. Costa ◽  
Carlos Capela
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Shot Peening ◽  
Stress Ratio ◽  
Stress Ratios ◽  
Crack Growth Rates ◽  
Hardness Values

Shot peening is an attractive technique for fatigue enhanced performance of metallic components, because it promotes crack initiation retardation and later crack growth. Engineering design based on fatigue crack propagation predictions applying the principles of fracture mechanics is commonly used in aluminum structures for aerospace engineering. The main purpose of present work was to analyze the effect of shot peening on the fatigue crack propagation of the 7475 aluminum alloy, under both constant amplitude loading and periodical overload blocks. The tests were performed on 4 and 8 mm thickness specimen's with stress ratios of 0.05 and 0.4. The analysis of the shot-peened surface showed a small increase of the micro-hardness values, due to the plastic deformations imposed by shot peening. The beneficial effect of surface peening on fatigue crack growth rates is quite limited to an increasing near the threshold. The specimens’ thickness has only marginal influence on the crack propagation, in opposite to the stress ratio. Periodic overload blocks of 300 cycles promotes a reduction of the fatigue crack growth rate for both intervals of 7,500 and 15,000 cycles.

scholarly journals Effects of Crack Size, Stress Ratio and Hydrogen on the Near Threshold Fatigue Crack Propagation of High Strength Steel

2005 ◽  
Vol 54 (12) ◽  
pp. 1237-1243 ◽  
Author(s):  
Kazutoshi YANAGIHARA ◽  
Satoshi OHYANAGI ◽  
Masanobu KUBOTA ◽  
Chu SAKAE ◽  
Yoshiyuki KONDO
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
High Strength Steel ◽  
Stress Ratio ◽  
High Strength ◽  
Crack Size ◽  
Near Threshold

Effects of stress ratio on fatigue crack propagation properties of submicron-thick free-standing copper films

2013 ◽  
Vol 61 (16) ◽  
pp. 6310-6327 ◽  
Author(s):  
Toshiyuki Kondo ◽  
Takahiro Imaoka ◽  
Hiroyuki Hirakata ◽  
Masayuki Sakihara ◽  
Kohji Minoshima
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Ratio ◽  
Copper Films ◽  
Free Standing ◽  
Effects Of Stress ◽  
Propagation Properties

Detecting Overload from Strain Information during Fatigue Crack Propagation under Negative Stress Ratio

2004 ◽  
Vol 32 (1) ◽  
pp. 11853 ◽  
Author(s):  
Chobin Makabe ◽  
Anindito Purnowidodo ◽  
Toshiyasu Sueyoshi ◽  
Takao Utsunomiya
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Ratio

Fundamental Research on Fatigue Properties of Closed-Packed Hexagonal Lattice Metal under Biaxial Stress

2007 ◽  
Vol 561-565 ◽  
pp. 167-170
Author(s):  
Yasumi Ito ◽  
Akira Shimamoto ◽  
Tetsuya Nemoto ◽  
Kazuharu Koide ◽  
Akira Inamori ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Magnesium Alloy ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Assisted Living ◽  
Stress Ratio ◽  
Hexagonal Lattice ◽  
Medical Implants ◽  
Biaxial Load ◽  
Joint Prostheses

Assisted living instruments and medical implants, such as wheelchairs and joint prostheses are usually subjected to biaxial or three-axial stresses instead of uniaxial stress. So, authors already developed a servo biaxial fatigue-testing machine, and clarified about the performance evaluation. Moreover, closed-packed hexagonal lattice metal, such as magnesium and titanium, is frequently used for assisted living instruments or medical implants. In this research, fatigue crack propagation tests of magnesium alloy AZ31B and pure titanium TP340C were conducted under conditions of biaxial and uniaxial loading by using a cruciform specimen in a bi-axial fatigue machine, in order to investigate the effect of non-singular stress cycling on the fatigue crack growth properties ⊿K-da/dN. From these comprehensive experiments, in the magnesium alloy, the re-markable effect was found in the specific biaxial load stress ratio on ⊿K-da/dN relation. When biaxial load stress ratio was 0.5, it turned out that the fatigue crack propagation rate of a magnesium alloy becomes very slow. On the other hand, in the titanium, it was confirmed that there is a little influence of a biaxial load stress ratio on ⊿KⅠ -da/dN relation.

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