Microcrack initiation mechanism of a duplex stainless steel under very high cycle fatigue loading condition: The significance of load partitioning and micro residual stresses

2020 ◽  
Vol 199 ◽  
pp. 278-287
Author(s):  
Hongwang Fu ◽  
Benjamin Dönges ◽  
Ulrich Krupp ◽  
Ullrich Pietsch ◽  
Claus-Peter Fritzen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Loading Condition ◽  
High Cycle Fatigue ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Initiation Mechanism ◽  
Very High Cycle Fatigue ◽  
Microcrack Initiation ◽  
Very High

High-cycle and very-high-cycle fatigue behavior of a stainless steel for air-conditioning compressor valve plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xu Jia ◽  
Yang Ou Xiang ◽  
Hu Yuan Pei ◽  
Song Wei
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Air Conditioning ◽  
High Cycle Fatigue ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Content Type ◽  
Very High Cycle Fatigue ◽  
Load Characteristics ◽  
Very High

PurposeThe investigations could guide the structural design and fatigue life prediction of air-conditioning compressor valve plates.Design/methodology/approachThe High-Cycle Fatigue (HCF) and Very-High-Cycle Fatigue (VHCF) behaviors of stainless steel used for air-conditioning compressor valve plates were investigated. Monotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure.FindingsThe crack initiation can be observed as the arc-shaped cracks at both sides of specimens and Y-shaped crack bifurcation in the specimens. Moreover, the middle section and the cracks at both ends are not connected to the surface of the specimen. The stress-life results of the materials under two directions (vertical and horizontal) were provided to examine the difference in fatigue strength.Originality/valueMonotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure. Based on the experimental data, the results indicate that specimens under cyclic loading conditions could demonstrate better mechanical performance than static loadings.

PSBs and Non-Propagation of Small Surface and Interior Cracks in Polycrystalline Copper

2013 ◽  
Vol 592-593 ◽  
pp. 777-780 ◽  
Author(s):  
Stefanie E. Stanzl-Tschegg ◽  
Bernd M. Schönbauer
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Lower Stress ◽  
Small Surface ◽  
Loading Method ◽  
Very High Cycle Fatigue ◽  
Small Cracks ◽  
Number Of Cycles ◽  
Very High

PSB formation and its relevance for an eventual fatigue limit of polycrystalline electrolytic copper was studied in the very-high cycle fatigue regime with the ultrasound fatigue loading method. PSBs are formed at much lower stress/strain amplitudes than reported in earlier literature, if a high enough number of cycles is applied. Fatigue fracture takes place at approximately 50% higher amplitudes than needed for PSB formation, which is likewise in contrast to former literature results. Non-propagation of small cracks, originating from intrusions or PSB-induced non-propagating grain-boundary cracks are made responsible for this different material response.

scholarly journals Very High Cycle Fatigue Crack Initiation Mechanism in Nugget Zone of AA 7075 Friction Stir Welded Joint

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Chao He ◽  
Kazuhiro Kitamura ◽  
Kun Yang ◽  
Yong-jie Liu ◽  
Qing-yuan Wang ◽  
...  
Keyword(s):  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Welded Joint ◽  
Cycle Fatigue ◽  
Nugget Zone ◽  
Initiation Mechanism ◽  
Friction Stir ◽  
Very High Cycle Fatigue ◽  
Aa 7075 ◽  
Very High

Very high cycle fatigue behavior of nugget zone in AA 7075 friction stir welded joint was experimentally investigated using ultrasonic fatigue testing system (20 kHz) to clarify the crack initiation mechanism. It was found that the fatigue strength of nugget zone decreased continuously even beyond 107 cycles with no traditional fatigue limits. Fatigue cracks initiated from the welding defects located at the bottom side of the friction stir weld. Moreover, a special semicircular zone could be characterized around the crack initiation site, of which the stress intensity factor approximately equaled the threshold of fatigue crack propagation rate. Finally, a simplified model was proposed to estimate the fatigue life by correlating the welding defect size and applied stress. The predicted results are in good agreement with the experimental results.

Sign in / Sign up

Export Citation Format

Share Document