Multiaxial fatigue assessment of welded connections in railway steel bridge under constant and variable amplitude loading

2018 ◽  
Vol 14 (1) ◽  
pp. 21-33 ◽  
Author(s):  
K.R. Praveen ◽  
S.S. Mishra ◽  
Prasad Babu ◽  
Andrea Spagnoli ◽  
Andrea Carpinteri
Keyword(s):  
Multiaxial Fatigue ◽  
Steel Bridge ◽  
Variable Amplitude Loading ◽  
Fatigue Assessment ◽  
Variable Amplitude

Fatigue assessment of metallic components under uniaxial and multiaxial variable amplitude loading

2018 ◽  
Vol 41 (6) ◽  
pp. 1306-1317 ◽  
Author(s):  
A. Carpinteri ◽  
S. Vantadori ◽  
T. Łagoda ◽  
A. Karolczuk ◽  
M. Kurek ◽  
...  
Keyword(s):  
Variable Amplitude Loading ◽  
Fatigue Assessment ◽  
Variable Amplitude

scholarly journals The elasto-plastic Point Method to estimate fatigue lifetime of notched metallic materials under variable amplitude multiaxial fatigue loading

2019 ◽  
Vol 300 ◽  
pp. 13004
Author(s):  
Namiq Zuhair Faruq ◽  
Luca Susmel
Keyword(s):  
Biaxial Loading ◽  
Fatigue Loading ◽  
Medium Carbon Steel ◽  
Multiaxial Fatigue ◽  
Point Method ◽  
Assessment Procedure ◽  
Fatigue Lifetime ◽  
Fatigue Assessment ◽  
Variable Amplitude ◽  
Strain Components

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.

Comparison of multiaxial fatigue damage models under variable amplitude loading

2012 ◽  
Vol 26 (11) ◽  
pp. 3439-3446 ◽  
Author(s):  
Hong Chen ◽  
De-Guang Shang ◽  
Yu-Jie Tian ◽  
Jian-Zhong Liu
Keyword(s):  
Fatigue Damage ◽  
Multiaxial Fatigue ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Damage Models

A New Multiaxial Fatigue Testing Method for Variable-Amplitude Loading and Stress Ratio

2003 ◽  
Author(s):  
Tommy J. George ◽  
M.-H. Herman Shen ◽  
Theodore Nicholas ◽  
Charles J. Cross
Keyword(s):  
Fatigue Test ◽  
Fatigue Testing ◽  
Low Cost ◽  
Design Procedure ◽  
Element Model ◽  
Multiaxial Fatigue ◽  
Biaxial Stress ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Stress Ratios

A new vibration-based multiaxial fatigue testing methodology for assessing high cycle turbine engine material fatigue strength at various stress ratios is presented. The idea is to accumulate fatigue energy on a base-excited plate specimen at high frequency resonant modes and to complete a fatigue test in a much more efficient way at very low cost. The methodology consists of: (1) a topological design procedure, incorporating a finite element model, to characterize the shape of the specimens for ensuring the required stress state/pattern, (2) a vibration feedback empirical procedure for achieving the high cycle fatigue experiments with variable-amplitude loading, and finally (3) a yielding procedure for achieving various uniaxial stress ratios. The performance of the methodology is demonstrated by the experimental results from mild steel, 6061-T6 aluminum, and Ti-6Al-4V plate specimens subjected to fully reversed bending for both uniaxial and biaxial stress states. Results are compared with those produced using traditional fatigue test machines.

Multiaxial Fatigue Under Variable Amplitude Loads

1999 ◽  
Vol 121 (3) ◽  
pp. 286-293 ◽  
Author(s):  
K. S. Kim ◽  
J. C. Park ◽  
J. W. Lee
Keyword(s):  
Shear Strain ◽  
Strain Range ◽  
Multiaxial Fatigue ◽  
Test Material ◽  
Computation Method ◽  
Strain History ◽  
Maximum Shear Strain ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Rainflow Cycle Counting

Multiaxial fatigue under variable amplitude loading is investigated using Kandil et al.’s parameter, rainflow cycle counting on the shear strain history, and the Miner-Palmgren damage rule. Fatigue data are obtained on tubular specimens of S45C steel under proportional and nonproportional tension-torsion loading. The approaches using the maximum shear strain range (Δγmax) plane and the maximum damage (Dmax) plane as the critical plane are investigated. The damage is computed for each reversal or for each cycle. The results show that both Δγmax and Dmax approaches yield acceptable fatigue lives irrespective of the damage computation method. Damage computation for each reversal tends to shift fatigue life toward the nonconservative side for some nonproportional loading. It is concluded that the overall procedure used in this study is viable for multiaxial life prediction under variable amplitude loading for the test material.

scholarly journals Integral treatment of butt joints for the fatigue life assessment in the low cycle fatigue regime

2020 ◽  
Author(s):  
Benjamin Möller
Keyword(s):  
Fatigue Life ◽  
Life Assessment ◽  
Cyclic Behavior ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Butt Joints ◽  
Variable Amplitude Loading ◽  
Fatigue Assessment ◽  
Variable Amplitude ◽  
Integral Treatment

Abstract The framework for a fatigue assessment of welded joints under service loading conditions of crane structures from the low cycle to the high cycle fatigue regime includes the consideration of elastic-plastic material behavior, variable amplitude loading, and acceptable calculation times. Therefore, an integral treatment of butt joints has been developed for fatigue life estimation. The butt weld is considered in its entirety, so that it can be described by its cyclic behavior. The evaluation of the cyclic stress-strain behavior and tri-linear strain-life curves of butt joints for different high-strength, fine-grained structural steels, derived by strain-controlled fatigue tests, is the basis for this description. This procedure is not limited to conventionally applied gas metal arc welding only, but also the fatigue assessment of laser beam welding is possible, for example. Cyclic transient effects have been analyzed and a distinctive cyclic softening is described by linearization of Ramberg-Osgood parameters, depending on the damage content of each cycle derived from constant amplitude, strain-controlled tests. On the basis of the cyclic behavior in combination with memory and Masing behavior, a simulation of the stress-strain paths of investigated butt welds, under constant and variable amplitude loading, has been performed. Damage parameters are used to accumulate the damage cycle by cycle in order to derive the fatigue lifetime. Finally, calculated fatigue lives were compared with experimentally determined lives, showing the impact of this procedure.

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