Experimental results generated under multiaxial fatigue loading

2009 ◽  
pp. 280-563
Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 116
Author(s):  
František Fojtík ◽  
Jan Papuga ◽  
Martin Fusek ◽  
Radim Halama

The paper describes results of fatigue strength estimates by selected multiaxial fatigue strength criteria in the region of high-cycle fatigue, and compares them with own experimental results obtained on hollow specimens made from ČSN 41 1523 structural steel. The specimens were loaded by various combinations of load channels comprising push–pull, torsion, bending and inner and outer pressures. The prediction methods were validated on fatigue strengths at seven different numbers of cycles spanning from 100,000 to 10,000,000 cycles. No substantial deviation of results based on the selected lifetime was observed. The PCRN method and the QCP method provide best results compared with other assessed methods. The results of the MMP criterion that allows users to evaluate the multiaxial fatigue loading quickly are also of interest because the method provides results only slightly worse than the two best performing solutions.


2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Zengliang Gao ◽  
Tianwen Zhao ◽  
Xiaogui Wang ◽  
Yanyao Jiang

Uniaxial, torsion, and axial-torsion fatigue experiments were conducted on a pressure vessel steel, 16MnR, in ambient air. The uniaxial experiments were conducted using solid cylindrical specimens. Axial-torsion experiments employed thin-walled tubular specimens subjected to proportional and nonproportional loading. The true fracture stress and strain were obtained by testing solid shafts under monotonic torsion. Experimental results reveal that the material under investigation does not display significant nonproportional hardening. The material was found to display shear cracking under pure shear loading but tensile cracking under tension-compression loading. Two critical plane multiaxial fatigue criteria, namely, the Fatemi–Socie criterion and the Jiang criterion, were evaluated based on the experimental results. The Fatemi–Socie criterion combines the maximum shear strain amplitude with a consideration of the normal stress on the critical plane. The Jiang criterion makes use of the plastic strain energy on a material plane as the major contributor to the fatigue damage. Both criteria were found to correlate well with the experiments in terms of fatigue life. The predicted cracking directions by the criteria were less satisfactory when comparing with the experimentally observed cracking behavior under different loading conditions.


2019 ◽  
Vol 300 ◽  
pp. 13004
Author(s):  
Namiq Zuhair Faruq ◽  
Luca Susmel

The present paper deals with the formulation and implementation of a novel fatigue lifetime estimation technique suitable for designing notched components against multiaxial fatigue. This fatigue assessment procedure was devised by combining the Modified Manson-Coffin Curve Method and the Shear Strain-Maximum Variance Method with the elasto-plastic Point Method. The accuracy of the approach being proposed was checked against a large number of experimental results that were generated by testing notched cylindrical samples of medium-carbon steel En8. These tests were run under proportional/non-proportional constant/variable amplitude biaxial loading, with the effect of non-zero mean stresses and different frequencies between the axial and torsional stress/strain components being also investigated. The results from this validation exercise demonstrate that the novel multiaxial fatigue assessment methodology being proposed is highly accurate, with its systematic usage resulting in predictions falling within an error factor of 2. This remarkable level of accuracy is very promising especially in light of the fact that this approach can be applied by directly post-processing the results from elasto-plastic Finite Element (FE) models solved using commercial codes.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1587 ◽  
Author(s):  
Krzysztof Kluger ◽  
Aleksander Karolczuk ◽  
Szymon Derda

This study presents the life-dependent material parameters concept as applied to several well-known fatigue models for the purpose of life prediction under multiaxial and non-zero mean loading. The necessity of replacing the fixed material parameters with life-dependent parameters is demonstrated. The aim of the research here is verification of the life-dependent material parameters concept when applied to multiaxial fatigue loading with non-zero mean stress. The verification is performed with new experimental fatigue test results on a 7075-T651 aluminium alloy and S355 steel subjected to multiaxial cyclic bending and torsion loading under stress ratios equal to R = −0.5 and 0.0, respectively. The received results exhibit the significant effect of the non-zero mean value of shear stress on the fatigue life of S355 steel. The prediction of fatigue life was improved when using the life-dependent material parameters compared to the fixed material parameters.


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