scholarly journals Low-Cycle Fatigue Fracture Phenomenon of Bended Copper Pipes under Internal Pressure

2012 ◽  
Vol 61 (6) ◽  
pp. 550-555
Author(s):  
Yoichi TAMIYA
Keyword(s):  
Internal Pressure ◽  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue

Ultra-low Cycle Fatigue Fracture of High-Strength Steel Q460C and Its Weld

2018 ◽  
Vol 30 (11) ◽  
pp. 04018280 ◽  
Author(s):  
Fei Yin ◽  
Lu Yang ◽  
Liang Zong ◽  
Xiyue Liu ◽  
Yuanqing Wang
Keyword(s):  
Fatigue Fracture ◽  
High Strength Steel ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Cycle Fatigue

The Revised Universal Slope Method to Predict the Low-Cycle Fatigue Lives of Elbow and Tee Pipes

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Hiun Nagamori ◽  
Koji Takahashi
Keyword(s):  
Experimental Data ◽  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Experimental Studies ◽  
High Accuracy ◽  
Universal Method ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Slope Method ◽  
Stress States

The stress states of elbow and tee pipes are complex and different from those of straight pipes. The low-cycle fatigue lives of elbows and tees cannot be predicted by Manson's universal slope method; however, a revised universal method proposed by Takahashi et al. was able to predict with high accuracy the low-cycle fatigue lives of elbows under combined cyclic bending and internal pressure. The objective of this study was to confirm the validity of the revised universal slope method for the prediction of low-cycle fatigue behaviors of elbows and tees of various shapes and dimensions under conditions of in-plane bending and internal pressure. Finite element analysis (FEA) was carried out to simulate the low-cycle fatigue behaviors observed in previous experimental studies of elbows and tees. The low-cycle fatigue behaviors, such as the area of crack initiation, the direction of crack growth, and the fatigue lives, obtained by the analysis were compared with previously obtained experimental data. Based on this comparison, the revised universal slope method was found to accurately predict the low-cycle fatigue behaviors of elbows and tees under internal pressure conditions regardless of differences in shape and dimensions.

Investigation on Fatigue Damage of the Al5Zn2Mg High Strength Aluminum Alloy

2013 ◽  
Vol 721 ◽  
pp. 12-15 ◽  
Author(s):  
Xian Liang Sun ◽  
Ai Qin Tian ◽  
Wen Bin Chen ◽  
San San Ding ◽  
Shang Lei Yang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Grain Boundary ◽  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Alloy Sample ◽  
Cycle Fatigue ◽  
High Strength Aluminum Alloy ◽  
Propagation Zone

The fatigue fracture and the microstructure of Al5Zn2Mg high strength aluminum alloy were observed by OM, SEM and TEM, and the low cycle fatigue properties were tested and analyzed. The results of experimentation show that the low cycle fatigue life of Al5Zn2Mg high strength aluminum alloy is 9.28×104 cycle in R=0.1, f=8Hz, and σmax=0.75σb. The tensile strength is 444MPa. The fatigue fracture is composed of the initiation zone, the propagation zone, and the sudden fracture zone, which is characteristic of a mixed-type fatigue fracture. The fatigue crack initiates in the surface of Al5Zn2Mg aluminum alloy sample, while there is no fatigue striation in fatigue crack propagation zone. The η′(MgZn2) transitional strengthening phases are precipitated in Al5Zn2Mg aluminum alloy, and mostly distributed in grain boundary. The diameter of η′ strengthening phase is fine, about is 10nm. There is none precipitated zone in width nearby the grain boundary

Extremely - low cycle fatigue fracture of Q235 steel at different stress triaxialities

2020 ◽  
Vol 169 ◽  
pp. 106060
Author(s):  
Zeshen Li ◽  
Jinjun Xu ◽  
Cristoforo Demartino ◽  
Keshi Zhang
Keyword(s):  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Q235 Steel

Analysis on Low Cycle Fatigue Life and Fatigue Fracture Surface Morphology of TC25 Titanium Alloy

2016 ◽  
Vol 697 ◽  
pp. 652-657
Author(s):  
Rong Guo Zhao ◽  
Yi Yan ◽  
Yong Zhou Jiang ◽  
Xi Yan Luo ◽  
Qi Bang Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Fracture Surface ◽  
Crack Growth ◽  
Fatigue Fracture ◽  
Low Cycle Fatigue ◽  
Observation System ◽  
Cycle Fatigue ◽  
Stress Strain

At room temperature, the low cycle fatigue tests for smooth specimens of TC25 titanium alloy under various stress ranges are operated at a CSS280I-20w Electro Hydraulic Servo Universal Testing Machine with a microscopic observation system, and the low cycle fatigue lifetimes are measured. Based upon the analysis of stress-strain hysteresis loop of low cycle fatigue of TC25 titanium alloy, a simplified Manson-Coffin formula is derived according to both the experimental characteristics and the stress-strain constitutive model, the fatigue lifetimes are plotted against stress ranges, and a stress-fatigue life curve for TC25 titanium alloy is obtained by the linear regression analysis method. Finally, the fracture surface morphologies of TC25 specimens are investigated using a JSM-6360 Scanning Electron Microscopy, and the fatigue fracture mechanisms of low cycle fatigue are studied. It shows that the plastic deformations are mainly formed at the accelerated fracture stage, and various shear lips can be observed on the fracture surfaces, which demonstrates that the shear stress results in the final rupture of TC25 titanium alloy. During the fracture of low cycle fatigue, the cleavage nucleation leads to the formation of fatigue crack initiation region, the fatigue crack growth exhibits a mixed transgranular and intergranular crack growth mode, and in the final rupture region, the fracture surface of low cycle fatigue of TC25 titanium alloy appears as a typical semi-brittle fracture mode.

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