Fatigue crack deflection and fracture surface contact: Micromechanical models

1985 ◽  
Vol 16 (2) ◽  
pp. 249-260 ◽  
Author(s):  
S. Suresh
Keyword(s):  
Fatigue Crack ◽  
Fracture Surface ◽  
Crack Deflection ◽  
Surface Contact ◽  
Micromechanical Models

scholarly journals The influence of fracture surface contact in fatigue crack propagation of material having texture under Mode II loading

2018 ◽  
Vol 13 ◽  
pp. 1088-1092
Author(s):  
Taro Suemasu ◽  
Motomichi Koyama ◽  
Shigeru Hamada ◽  
Masaharu Ueda ◽  
Hiroshi Noguchi
Keyword(s):  
Fatigue Crack ◽  
Fracture Surface ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Mode Ii ◽  
Surface Contact ◽  
Mode Ii Loading

Experimental–computational estimation of rough fracture surface contact stresses

1998 ◽  
Vol 249 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
D.A Mendelsohn ◽  
T.S Gross ◽  
R.U Goulet ◽  
M Zhouc
Keyword(s):  
Fracture Surface ◽  
Contact Stresses ◽  
Computational Estimation ◽  
Rough Fracture ◽  
Surface Contact

Estimation of Applied Stress at Fatigue Cracks of a Single Crystal Superalloy

2020 ◽  
Author(s):  
Daisuke Kobayashi ◽  
Katsuhiro Takama ◽  
Tomihiko Ikeda
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Fracture Surface ◽  
Single Crystal ◽  
Crack Growth ◽  
Applied Stress ◽  
Fatigue Crack Growth Rate ◽  
Single Crystal Superalloy

Abstract Needless to say, it is important to estimate the stress applied to a material when conducting failure analysis. In recent years, a material assessment method using electron back-scatter diffraction (EBSD) has been developed. It has been reported that a characteristic misorientation distribution corresponding to the fracture mode is seen in cross-sectional EBSD observation near the fracture surface of a Ni-based superalloy. Furthermore, the authors discovered EBSD striations on the crack cross-section, which is formed with each fatigue crack growth during a turbine shut-down process. This was discovered in misorientation analysis on a single-crystal superalloy blade used in a commercial land-based gas turbine. Since Ni-based superalloys have high deformation resistance, they do not undergo enough ductile deformation to form striations at the crack tip on the fracture surface during fatigue crack growth, and, as a result, striations corresponding to cyclic loadings are rarely observed in fractography. Even in such a Ni-based superalloy with brittle crack growth, the fatigue crack growth rate and the applied stress can be estimated by measuring EBSD striation spacing in misorientation analysis. However, a practical problem in assessment is that the resolution limit fixed with field emission scanning electron microscopes (FE-SEM) determine the range in which crack growth rate can be assessed. Hence, it is difficult to clearly discriminate the EBSD striations when the fatigue crack growth rate is too low, such as in the low stress intensity factor range (ΔK) region. The applied stress can be calculated from ΔK. Therefore, in this paper, in order to estimate the applied stress during fatigue crack growth, we focused on estimating ΔK by measuring the plastic zone size along the crack growth.

Effect of Partial Crack Surface Contact on Fatigue Crack Growth in Residual Stress Fields

1989 ◽  
pp. 84-89 ◽  
Author(s):  
Akira Todoroki ◽  
Hideo Kobayashi ◽  
Haruo Nakamura
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Surface ◽  
Stress Fields ◽  
Surface Contact

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.

312 The Study on Small Fatigue Crack Deflection Mechanism in α-Brass focusing on the Relative between Crack Front Geometry and Slip Surface

2012 ◽  
Vol 2012.50 (0) ◽  
pp. 31201-31202
Author(s):  
Kenta Banba ◽  
Hiroyuki Akebono ◽  
Masahiko Kato ◽  
Atsushi Sugeta
Keyword(s):  
Fatigue Crack ◽  
Crack Front ◽  
Slip Surface ◽  
Crack Deflection ◽  
Small Fatigue Crack
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