2713 Unsteady hydrogen diffusion analysis around the crack tip on cyclic loading

2007 ◽  
Vol 2007.20 (0) ◽  
pp. 615-616
Author(s):  
Hirokazu KOTAKE ◽  
Ryosuke MATSUMOTO ◽  
Shinya TAKETOMI ◽  
Noriyuki MIYAZAKI
Keyword(s):  
Cyclic Loading ◽  
Hydrogen Diffusion ◽  
Crack Tip ◽  
Diffusion Analysis

303 Hydrogen Diffusion Analysis in Materials with a Notch under Cyclic Loading

2010 ◽  
Vol 2010.63 (0) ◽  
pp. 85-86
Author(s):  
Hiroshi Kanayama ◽  
Masao Ogino ◽  
Hiroshi Notsu ◽  
Toshihiro Setojima
Keyword(s):  
Cyclic Loading ◽  
Hydrogen Diffusion ◽  
Diffusion Analysis

Flow Controllability of Hydrogen Diffusion Driven by Local Stress Field for Steel under Cyclic Loading Condition

2012 ◽  
Vol 326-328 ◽  
pp. 626-631 ◽  
Author(s):  
Toshihito Ohmi ◽  
A.Toshimitsu Yokobori Jr. ◽  
Kenichi Takei
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Hydrogen Embrittlement ◽  
Loading Condition ◽  
Hydrogen Diffusion ◽  
Local Stress ◽  
Cyclic Loading Condition ◽  
Diffusion Analysis ◽  
Concentration Behavior ◽  
Local Stress Field

The hydrogen diffuses and accumulates at the stress concentration area like a crack tip and it causes hydrogen embrittlement. To clarify the mechanism of hydrogen embrittlement, it is important to obtain the hydrogen concentration behavior. However, experimental detection is not feasible due to the high diffusivity of hydrogen and numerical analyses have been preceded. In this paper, by using a finite element and finite difference coupled method at which the diffusion analysis is performed by FDM coupled with the stress analysis by FEM, the analyses of hydrogen diffusion were conducted under cyclic loading conditions.

Transient hydrogen diffusion analyses coupled with crack-tip plasticity under cyclic loading

2008 ◽  
Vol 85 (8) ◽  
pp. 540-549 ◽  
Author(s):  
Hirokazu Kotake ◽  
Ryosuke Matsumoto ◽  
Shinya Taketomi ◽  
Noriyuki Miyazaki
Keyword(s):  
Cyclic Loading ◽  
Hydrogen Diffusion ◽  
Crack Tip ◽  
Crack Tip Plasticity

Effects of Dynamic Strain-Aging and Cyclic Loading on Fracture Behavior of Ferritic Steels

2002 ◽  
Author(s):  
K. Linga Murty ◽  
Chang-Sung Seok
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Strain Aging ◽  
Crack Tip ◽  
Load Ratio ◽  
Seismic Loading ◽  
Dynamic Strain ◽  
Ferritic Steels ◽  
Bend Tests ◽  
Point Bend

Ferritic steels commonly used for pressure vessels and reactor supports in light water reactors (LWRs) exhibit dynamic strain aging (DSA) resulting in decreased ductility and toughness. In addition, recent work indicated decreased toughness during reverse-cyclic loading that has implications on reliability of these structures under seismic loading conditions. We summarize some of our recent work on these aspects along with synergistic effects, of interstitial impurity atoms (IIAs) and radiation induced point defects, that result in interesting beneficial effects of radiation exposure at appropriate temperature and strain-rate conditions. Radiation-defect interactions were investigated on pure iron, Si-killed mild steel, A533B, A516, A588 and other reactor support and vessel steels. In all cases, DSA is seen to result in decreased ductility accompanied by increased work-hardening parameter. In addition to mechanical property tests, fracture toughness is investigated on both A533B and A516 steels. While dips in fracture toughness are observed in A533B steel in the DSA region, A516 steel exhibited at best a plateau. The reasons could lie in the applied strain-rates; while J1c tests were performed on A533B steel using 3-point bend tests on Charpy type specimens, CT specimens were used for A516 steel. However, tensile and 3-point bend tests on similar grade A516 steel of different vintage did exhibit distinct drop in the energy to fracture. Load-displacement curves during J1c tests on CT specimens did show load drops in the DSA regime. The effect of load ratio (R) on J versus load-line displacement curves for A516 steel is investigated from +1 to −1 at a fixed normalized incremental plastic displacement of 0.1 (R = 1 corresponds to monotonic loading). We note that J-values are significantly reduced with decreasing load ratio. The work-hardening characteristics on the fracture surfaces were studied following monotonic and cyclic loading fracture tests along with the stress-field analyses. From the hardness and the ball-indentation tests, it was shown that decreased load ratio (R) leads to more strain hardening at the crack tip resulting in decreased fracture toughness. From the stress field analysis near the crack tip of a compact tension fracture toughness test specimen, a cycle of tensile and compressive loads is seen to result in tensile residual stresses (which did not exist at the crack tip before). These results are important to evaluations of flawed-structures under seismic loading conditions, i.e. Leak-Before-Break (LBB) and in-service flaw evaluation criteria where seismic loading is addressed. In addition, studies on fast vs total (thermal+fast) neutron spectra revealed unexpected results due to the influence of radiation exposure on source hardening component of the yield stress; grain-size of pure iron plays a significant role in these effects.

Crack Tip Growth Rate Model for Cyclic Loading

1984 ◽  
pp. 229-237 ◽  
Author(s):  
F. Ellyin ◽  
C. O. A. Fakinlede
Keyword(s):  
Growth Rate ◽  
Cyclic Loading ◽  
Tip Growth ◽  
Crack Tip ◽  
Rate Model

Crack tip fields at crack initiation and growth under monotonic and large amplitude cyclic loading: Experimental and FE analyses

2020 ◽  
Vol 141 ◽  
pp. 105889
Author(s):  
Jin-Ha Hwang ◽  
Hune-Tae Kim ◽  
Yun-Jae Kim ◽  
Hyun-Suk Nam ◽  
Jin-Weon Kim
Keyword(s):  
Cyclic Loading ◽  
Crack Initiation ◽  
Large Amplitude ◽  
Crack Tip ◽  
Crack Tip Fields
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