On the Influence of Strain-Path in Multiaxial Fatigue Failure

1987 ◽  
Vol 109 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Han C. Wu ◽  
C. C. Yang
Keyword(s):  
Crack Initiation ◽  
Strain Path ◽  
Path Dependence ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Crack Initiation And Propagation ◽  
Torsional Fatigue ◽  
Initiation And Propagation ◽  
Strain Paths ◽  
Tubular Specimens

A set of strain-controlled experiments has been performed on tubular specimens of annealed stainless steel. The strain-paths are designed to highlight the characteristics of path-dependence in the axial-torsional fatigue tests. Fatigue life, directions of crack initiation, and propagation are the subjects of interest in this investigation. They have been observed to be strongly influenced by the strain-path. For all the specimens tested, crack initiation was in the tensile mode.

Study on Micro-Mechanism of Crack Initiation and Propagation Induced by Inclusion in Ultra-High Strength Steel

2007 ◽  
Vol 353-358 ◽  
pp. 1185-1190 ◽  
Author(s):  
Yan Ping Zeng ◽  
Hong Mei Fan ◽  
Xi Shu Wang ◽  
Xi Shan Xie
Keyword(s):  
Crack Initiation ◽  
High Strength Steel ◽  
Harmful Effect ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Ultra High Strength Steel

Specially designed SEM in-situ tensile and fatigue tests have been conducted to trace the entire process of crack initiation and propagation till fracture in an ultra-high strength steel MA250. TiN is a typical inclusion and its average size is in the range of 8~10μm in MA250 steel. The micro-mechanism of the effect of TiN inclusion on crack initiation and propagation at tensile and fatigue tests both have been studied in detail. Experimental results show the harmful effect of TiN on tensile and fatigue properties both. This work is helpful to establish the practical life prediction model for the characteristic inclusion parameters in ultra-high strength steel components. It also enlightens us to eliminate TiN in the further development of ultra-high strength steels.

Three Dimensional Fractography of Extruded Age-Hardened Al Alloys Subjected to Fatigue Tests

2018 ◽  
Vol 940 ◽  
pp. 89-93
Author(s):  
Yuzo Nakamura ◽  
Ryuichi Iwamoto ◽  
Yuta Kurigeno ◽  
Hiroki Kamibayashi ◽  
Kohji Kariya ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Crack Initiation ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Al Alloys ◽  
Metal Fatigue ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
The Difference ◽  
Insight Into

Observation of fracture surface in metal fatigue is one of the most significant procedures to get insight into the cause and mechanism of crack initiation and propagation. In the present study, age-hardened 2017-T4 and 7075-T6 Al alloys having the extrusion texture were fatigue tested in low and high humidities, and their fracture surfaces were examined using a three dimensional (3D) surface analyzer. In addition to the microscopic observations conducted, it is shown that these 3D analyses provide important information on the difference in crack propagation depending on the stress level and environment.

Evaluation of multiaxial fatigue life prediction criteria for Ni-based superalloy GH4169

2017 ◽  
Vol 232 (10) ◽  
pp. 1823-1837 ◽  
Author(s):  
ZR Wu ◽  
X Li ◽  
L Fang ◽  
YD Song
Keyword(s):  
Life Prediction ◽  
Equivalent Strain ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Maximum Shear Strain ◽  
Torsional Fatigue ◽  
Prediction Criteria ◽  
Satisfactory Prediction ◽  
Tubular Specimens ◽  
Song Parameter

Fatigue tests under multiaxial loading were conducted on Ni-based superalloy GH4169 tubular specimens. The microstructures of fracture surfaces under different loading paths were compared. Several multiaxial fatigue criteria were reviewed and evaluated with multiaxial fatigue test data. The criteria of equivalent strain, maximum shear strain and Kandil–Brown–Miller provided unsatisfactory results for GH4169. Fatemi–Socie and Wu–Hu–Song parameters showed better life prediction abilities for this material. Minor modification has been introduced in Wu–Hu–Song parameter. The material constants of modified Wu–Hu–Song criterion are only dependent on torsional fatigue tests. The satisfactory prediction results based on modified Wu–Hu–Song model were obtained for GH4169.

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