<title>Durability patch: application of passive damping to high-cycle fatigue cracking on aircraft</title>

The United States Nuclear Regulatory Commission (USNRC) has approved several extended power uprates (EPU) for Boiling Water Reactors (BWRs). In some of the BWRs, operating at the higher EPU power levels and flow rates led to high-cycle fatigue damage of Steam Dryers, including the generation of loose parts. Since those failures occurred, all BWR owners proposing EPUs have been required by the USNRC to ensure that the steam dryers would not experience high-cycle fatigue cracking. This paper provides an overview of BWR steam dryer design; the fatigue failures that occurred at the Quad Cities (QC) nuclear power plants and their root causes; a brief history of BWR EPUs; and a discussion of steam dryer modifications/replacements, alternating stress mechanisms on steam dryers, and structural integrity evaluation methods (static and alternating stress).

Download Full-text

The effect of cubic-texture on fatigue cracking in a metastable β titanium alloy subjected to high-cycle fatigue

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2020.105872 ◽

2020 ◽

Vol 141 ◽

pp. 105872

Author(s):

Zhihong Wu ◽

Hongchao Kou ◽

Nana Chen ◽

Zhixin Zhang ◽

Fengming Qiang ◽

...

Keyword(s):

Titanium Alloy ◽

High Cycle Fatigue ◽

Fatigue Cracking ◽

Cycle Fatigue

Download Full-text

Initiation and Early-Stage Growth of Internal Fatigue Cracking Under Very-High-Cycle Fatigue Regime at High Temperature

Metallurgical and Materials Transactions A ◽

10.1007/s11661-020-05633-3 ◽

2020 ◽

Vol 51 (4) ◽

pp. 1575-1592 ◽

Cited By ~ 2

Author(s):

Z. Zhao ◽

F. Zhang ◽

C. Dong ◽

X. Yang ◽

B. Chen

Keyword(s):

High Temperature ◽

High Cycle Fatigue ◽

Early Stage ◽

Fatigue Cracking ◽

Cycle Fatigue ◽

Very High Cycle Fatigue ◽

Very High

Download Full-text

Cumulative Energy of Fatigue Cracking under Variable Amplitude Loading on the Example of C45 Steel

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.224.51 ◽

2014 ◽

Vol 224 ◽

pp. 51-56

Author(s):

Bogdan Ligaj

Keyword(s):

High Cycle Fatigue ◽

Stress Amplitude ◽

Fatigue Cracking ◽

Relative Difference ◽

Fatigue Tests ◽

Cycle Fatigue ◽

Constant Amplitude ◽

Cumulative Energy ◽

Variable Amplitude Loading ◽

Variable Amplitude

The article presents the results of low and high cycle fatigue tests of C45 steel for constant and variable amplitude loading in the stress and energy based approach. Values of the cumulated energy of plastic strain ΣΔWpl for programmed loading (at selected levels of stress amplitude Sa) were found to meet reliability criteria for results obtained in the condition of constant amplitude loading. (R= -1). It was also found that the results obtained in the energy based approach are characterised by a smaller range of relative difference changes (δ(N) = 0,77 to 1,17) than the results obtained in the stress based approach (δ(N) = 0,15 to 1,94). At stress level Sa = 428 MPa, (corresponding to yield point of C45 steel) value δ(N) is similar for the stress based approach and energy based approach.

Download Full-text

Analysis on a Gas Turbine Sealing Disk Structure and Material Strength

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.492.60 ◽

2014 ◽

Vol 492 ◽

pp. 60-70

Author(s):

Ben Wu Liu ◽

Jian Jun Wang ◽

Hui Yi Yuan

Keyword(s):

Gas Turbine ◽

High Cycle Fatigue ◽

Fatigue Cracking ◽

Structure Design ◽

Material Strength ◽

Cycle Fatigue ◽

Weak Point ◽

Manufacturing Defects ◽

Disk Structure ◽

Gas Turbine Compressor

To study the cause for fatigue cracking failure at pressure-balanced holes of a gas turbine compressor sealing disk, the damage impression, fractography and material composition of the damaged section were studied. Some manufacturing defects at the pressure-balanced hole edge were found, and the cracks at pressure-balanced holes are caused by high cycle fatigue (HCF). Stress analysis on the sealing disks of two types of different materials under assembly conditions and different structure dimensions were performed. The analysis results revealed that the high radial stress of pressure-balanced holes is the weak point of the original sealing disk design, and the manufacturing defects will prompt the cracking failure of holes. The studied work is valuable for performing similar fatigue failure analysis and new sealing disk structure design improvement.

Download Full-text