IHSI Effectiveness for Crack Propagation Observed at Hamaoka PLR Piping

2020 ◽  
Author(s):  
Hideki Yuya ◽  
Kouji Yamada ◽  
Takao Sasayama
Keyword(s):  
Heat Stress ◽  
Crack Growth ◽  
Growth Retardation ◽  
Ultrasonic Testing ◽  
Induction Heat ◽  
Primary Loop ◽  
Metallurgical Investigation ◽  
Weld Joints ◽  
Plant Construction ◽  
Crack Growth Retardation

Abstract Indications of Ultrasonic Testing (UT) of 4 weld joints in Primary Loop Recirculation (PLR) piping in Hamaoka unit-2 had been identified during the 20th outage (2004). Metallurgical investigation after cutting from 2 weld joins had been conducted because of its accessibility etc. The 4 weld joins had been welded at the plant construction (1978), operated and IHSI (Induction Heat Stress Improvement) had been performed during the 1st outage (1979). 25 years passed by until the metallurgical investigation. As a result of the investigation, crack growth retardation by the IHSI was confirmed since crack tip was round and plastically deformed.

Estimation of fatigue crack growth retardation due to crack branching

2004 ◽  
Vol 29 (4) ◽  
pp. 446-452 ◽  
Author(s):  
D.G. Pavlou ◽  
N.V. Vlachakis ◽  
M.G. Pavlou ◽  
V.N. Vlachakis
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Retardation ◽  
Crack Branching ◽  
Crack Growth Retardation

The Effect of Crack Growth Retardation when Comparing Constant Amplitude to Variable Amplitude Loading in an Aluminium Alloy

2014 ◽  
Vol 891-892 ◽  
pp. 948-954 ◽  
Author(s):  
Madeleine Burchill ◽  
Simon A. Barter ◽  
Michael Jones
Keyword(s):  
Growth Rate ◽  
Fatigue Life ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Growth Retardation ◽  
Crack Front ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Growth Increments ◽  
Crack Growth Retardation

It has often been observed that the growth of short fatigue cracks under variable amplitude (VA) cyclic loading is not well predicted when utilising standard constant amplitude (CA) crack growth rate/stress intensity data (da/dN v DK). This paper outlines a coupon fatigue test program and analyses, investigating a possible cause of crack growth retardation from CA-only testing. Various test loading spectra were developed with sub-blocks of VA and CA cycles, then using quantitative fractography (QF) the sub-block crack growth increments were measured. Comparison of these results found that, after establishing a consistent uniform crack front using a VA load sequence, the average crack growth rate then progressively slowed down with the number of subsequent CA load cycles applied. Further fractographic investigation of the fracture surface at the end of each CA and VA sub-block crack growth, identified significant crack front morphology differences. Thus it is postulated that a variation or deviation from an efficient crack path is a driver of local retardation in short crack growth during CA loading. This may be a source of error in analytical predictions of crack growth under VA spectra loading that may need to be considered in addition to other potential effects such asless closure whilst cracks are small. For aircraft designers, using solely CA data for fatigue life predictions this may result in non-conservative estimates of total crack fatigue life, producing unexpected failures or an increased maintenance burden.

Constraint corrected cycle-by-cycle analysis of crack growth retardation under variable amplitude fatigue loading

2019 ◽  
Vol 125 ◽  
pp. 199-209 ◽  
Author(s):  
Jie Zhang ◽  
Louis Muys ◽  
Steven De Tender ◽  
Nahuel Micone ◽  
Stijn Hertelé ◽  
...  
Keyword(s):  
Crack Growth ◽  
Growth Retardation ◽  
Fatigue Loading ◽  
Variable Amplitude ◽  
Variable Amplitude Fatigue ◽  
Crack Growth Retardation
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