Fatigue of Alumina Under Cyclic Torsion Loading

2009 ◽  
Vol 11 (7) ◽  
pp. 586-589 ◽  
Author(s):  
Thomas Schwind ◽  
Eberhard Kerscher ◽  
Karl-Heinz Lang
Keyword(s):  
Cyclic Torsion

Improved fatigue properties of ultrafine-grained copper under cyclic torsion loading

2013 ◽  
Vol 61 (15) ◽  
pp. 5857-5868 ◽  
Author(s):  
R.H. Li ◽  
Z.J. Zhang ◽  
P. Zhang ◽  
Z.F. Zhang
Keyword(s):  
Fatigue Properties ◽  
Cyclic Torsion ◽  
Ultrafine Grained

Fatigue Behavior of Circumferentially Notched Round Bars of Austenitic Stainless Steel Under Torsional and Axial Loads

2010 ◽  
Author(s):  
Masao Itatani ◽  
Keisuke Tanaka ◽  
Isao Ohkawa ◽  
Takehisa Yamada ◽  
Toshiyuki Saito
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Static Tension ◽  
Cyclic Torsion ◽  
Cyclic Tension ◽  
Crack Initiation Life

Fatigue tests of smooth and notched round bars of austenitic stainless steels SUS316NG and SUS316L were conducted under cyclic tension and cyclic torsion with and without static tension. Fatigue strength under fully reversed (R=−1) cyclic tension once increased with increasing stress concentration factor up to Kt=1.5, but it decreased from Kt=1.5 to 2.5. Fatigue life increased with increasing stress concentration under pure cyclic torsion, while it decreased with increasing stress concentration under cyclic torsion with static tension. From the measurement of fatigue crack initiation and propagation lives using electric potential drop method, it was found that the crack initiation life decreased with increasing stress concentration and the crack propagation life increased with increasing stress concentration under pure cyclic torsion. Under cyclic torsion with static tension, the crack initiation life also decreased with increasing stress concentration but the crack propagation life decreased or not changed with increasing stress concentration then the total fatigue life of sharper notched specimen decreased. It was also found that the fatigue life of smooth specimen under cyclic torsion with static tension was longer than that under pure cyclic torsion. This behavior could be explained based on the cyclic strain hardening under non-proportional loading and the difference in crack path with and without static tension.

Machine for testing the strength of structural materials under cyclic torsion at high temperatures

1974 ◽  
Vol 6 (6) ◽  
pp. 746-748
Author(s):  
V. N. Rudenko ◽  
A. S. Spivakov ◽  
A. F. Bezverbnyi
Keyword(s):  
High Temperatures ◽  
Structural Materials ◽  
Cyclic Torsion

scholarly journals Mechanism of formation of spiral grain in Aesculus stems: dissymmetry of deformation of stems caused by cyclic torsion

2015 ◽  
Vol 46 (3) ◽  
pp. 501-522 ◽  
Author(s):  
W. Pyszyński
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Secondary Cell Wall ◽  
Aesculus Hippocastanum ◽  
Mechanism Of Formation ◽  
Spiral Grain ◽  
Cyclic Torsion ◽  
The Right

The reversibility of deformation of young (3-10-year-old) <i>Aesculus hippocastanum</i> stems was investigated after subjecting them to alternate torsion to the right and left as well as the orientation of the microfibrillar helix in the main S<sub>2</sub> layer of the secondary cell wall in fibres. The studies demonstrated that residual torsions to the right are larger than to the left. The orientation of the fibrillar helix is always Z-wise. The dissymmetry of the mechanical properties of the stem may be responsible for the formation of Z (right-oriented) spiral grain in the stem of a tree undergoing torsions in various directions under the action of winds

scholarly journals The Prospects for Mechanical Ratcheting of Bulk Metallic Glasses

2003 ◽  
Vol 806 ◽  
Author(s):  
Wendelin J. Wright ◽  
R. H. Dauskardt ◽  
W. D. Nix
Keyword(s):  
Plastic Strain ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Tensile Axis ◽  
Uniaxial Stress ◽  
Temperature Deformation ◽  
Steel Alloys ◽  
Cyclic Torsion ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

ABSTRACTThe major mechanical shortcoming of metallic glasses is their limited ductility at room temperature. Monolithic metallic glasses sustain only a few percent plastic strain when subjected to uniaxial compression and essentially no plastic strain under tension. Here we describe a room temperature deformation process that may have the potential to overcome the limited ductility of monolithic metallic glasses and achieve large plastic strains. By subjecting a metallic glass sample to cyclic torsion, the glass is brought to the yield surface; the superposition of a small uniaxial stress (much smaller than the yield stress) should then produce increments in plastic strain along the tensile axis. This accumulation of strain during cyclic loading, commonly known as ratcheting, has been extensively investigated in stainless and carbon steel alloys, but has not been previously studied in metallic glasses. We have successfully demonstrated the application of this ratcheting technique of cyclic torsion with superimposed tension for polycrystalline Ti–6Al–4V. Our stability analyses indicate that the plastic deformation of materials exhibiting elastic–perfectly plastic constitutive behavior such as metallic glasses should be stable under cyclic torsion, however, results obtained thus far are inconclusive.

Ductile Crack Propagation Simulation of a Cylinder With a Through-Wall Circumferential Flaw Under Excessive Cyclic Torsion Loading

2014 ◽  
Author(s):  
Kiminobu Hojo ◽  
Daigo Watanabe ◽  
Shinichi Kawabata ◽  
Yasufumi Ametani
Keyword(s):  
Cyclic Loading ◽  
Crack Growth ◽  
Rotation Angle ◽  
Fe Analysis ◽  
The Other ◽  
J Integral ◽  
Ductile Crack ◽  
Elastic Plastic ◽  
Cyclic Torsion ◽  
Ductile Crack Growth

A lot of applications of elastic plastic FE analysis to flawed structural fracture behaviors of mode I have been investigated. On the other hand the analysis method has not been established for the case of the excessive cyclic torsion loading with mode II or III fracture. The authors tried simulating the fracture behavior of a cylinder-shaped specimen with a through-walled circumferential flaw subjected to excessive monotonic or cyclic loading by using elastic plastic FE analysis. Chaboche constitutive equation of the used FE code Abaqus was applied to estimate the elastic plastic cyclic behavior. As a result in the case of monotonic loading without crack extension, the relation of torque-rotation angle of the experiment was estimated well by the simulation. Also J-integral by the Abaqus’ function agreed with a simplified J-equation using the calculated torque-rotation angle relation. On the other hand under load controlled cyclic loading associated with ductile crack growth, the calculated torque-rotation angle relation did not agree with the experimental one because of high sensitivity of the used stress-strain curve. J-integral from Abaqus code did not increase regardless of the accumulated crack growth and plastic zone. Several simplified ΔJ calculations tried to explain the experimental ductile crack growth and it seemed that da/dN-ΔJ relation follows the Paris’ law. From these examinations an estimation procedure of the structures under excessive cyclic loading was proposed.

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