Study on displacement field near fatigue crack wake measured using DIC

2019 ◽  
Vol 2019.68 (0) ◽  
pp. 126
Author(s):  
Hayato NONOYAMA ◽  
Toshifumi KAKIUCHI ◽  
Bing YANG ◽  
M. Neil JAMES ◽  
Yoshihiko UEMATSU
Keyword(s):  
Fatigue Crack ◽  
Displacement Field ◽  
Crack Wake

Temperature Dependence of Fatigue Crack Growth in Low-Carbon Steel Under Gaseous Hydrogen

2019 ◽  
Author(s):  
Osamu Takakuwa ◽  
Yuhei Ogawa ◽  
Saburo Okazaki ◽  
Hisao Matsunaga ◽  
Saburo Matsuoka
Keyword(s):  
Fatigue Crack ◽  
Carbon Steel ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Carbon Steel ◽  
Gaseous Hydrogen ◽  
Low Carbon ◽  
Hydrogen Environment ◽  
Crack Wake ◽  
Higher Temperature

Abstract In order to elucidate the temperature dependence of hydrogen-assisted fatigue crack growth (HAFCG), the fatigue crack growth (FCG) test was performed on low-carbon steel JIS-SM490B according to ASTM E647 using compact tension (CT) specimen under 0.7 MPa (≈ 0.1 ksi) hydrogen-gas at room temperature (RT: 298 K (≈ 77 °F)) and 423 K (≈ 302 °F) at stress intensity factor range of ΔK = 30 MPa m1/2 (≈ 27 ksi in1/2). Electron backscatter diffraction (EBSD) observation was performed on the mid-thick section of CT specimen in order to investigate change in plasticity around the crack wake in gaseous hydrogen environment and how it changes due to temperature elevation. The obtained results showed the higher temperature, the lower intense of HAFCG as reported in our previous article. Plasticity around the crack wake became less in gaseous hydrogen environment, especially tested at 298 K. The propensity of the results obtained at higher temperature (423 K) can be separated into two cases: (i) intense plasticity occurs like tested in air, (ii) crack propagates straighter accompanying less plasticity like tested in gaseous hydrogen environment at 298 K. This implies macroscopic FCG rate is determined by combination of microscopic FCG rate in the case (i) and case (ii).

Fatigue crack propagation of AZ61 magnesium alloy under controlled humidity and visualization of hydrogen diffusion along the crack wake

2014 ◽  
Vol 59 ◽  
pp. 234-243 ◽  
Author(s):  
Yoshihiko Uematsu ◽  
Toshifumi Kakiuchi ◽  
Masaki Nakajima ◽  
Yuki Nakamura ◽  
Satoshi Miyazaki ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Magnesium Alloy ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Hydrogen Diffusion ◽  
Crack Wake ◽  
Az61 Magnesium Alloy

Effect of Interface Damage on Fatigue Crack Growth for SiC Fiber-Reinforced Ti-15-3 Matrix Composite

2000 ◽  
Author(s):  
Yoshihisa Tanaka ◽  
Yu-Fu Liu ◽  
Chitoshi Masuda
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Crack Opening Displacement ◽  
Test Temperature ◽  
Wear Behavior ◽  
Crack Opening ◽  
Opening Displacement ◽  
Crack Wake

Abstract The fatigue crack growth behavior in SiC (SCS-6) fiber reinforced Ti-15-3 matrix alloy composite subjected to a constant tension-tension loading mode was studied using single edge specimen in 2 × 10−3 Pa vacuum at 293 and 823K, with a frequency of 2 Hz, and a stress ratio of R = 0.1. Direct measurement of the fatigue crack length, and the crack opening displacement along the crack wake during the test were carried out by scanning electron microscope (SEM). The increase in the test temperature was found to lead to a decrease in the fatigue crack growth rate. The degradation of bridging fibers in the crack wake was severe for T = 293K, and this behavior was dependent of the test temperature. Fine particle-like debris was found on the fracture surface in the region of crack propagation in specimens tested at T = 823K. This is thought to be caused by the interface wear behavior. The crack opening displacement along the crack wake tested at T = 823K decreased with increasing crack length, and this tendency is dependent on the applied stress range. The associated increase in the crack tip shielding is explained on the basis of the crack closure due to the matrix relaxation by fatigue creep and the interface wear behavior.

scholarly journals Interpretation of hydrogen-assisted fatigue crack propagation in BCC iron based on dislocation structure evolution around the crack wake

2018 ◽  
Vol 156 ◽  
pp. 245-253 ◽  
Author(s):  
Domas Birenis ◽  
Yuhei Ogawa ◽  
Hisao Matsunaga ◽  
Osamu Takakuwa ◽  
Junichiro Yamabe ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Dislocation Structure ◽  
Structure Evolution ◽  
Crack Wake ◽  
Bcc Iron ◽  
Iron Based
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