A strategy for fatigue life estimation under variable amplitude loading in consideration of load sequence based on damage mechanics

2016 ◽  
Author(s):  
Yahui Li ◽  
Yunxia Chen
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Load Sequence

scholarly journals A Review on Fatigue Life Prediction Methods for Metals

2016 ◽  
Vol 2016 ◽  
pp. 1-26 ◽  
Author(s):  
E. Santecchia ◽  
A. M. S. Hamouda ◽  
F. Musharavati ◽  
E. Zalnezhad ◽  
M. Cabibbo ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Model ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Fatigue Life Prediction ◽  
Continuum Damage ◽  
Metallic Materials ◽  
Variable Amplitude Loading ◽  
Variable Amplitude

Metallic materials are extensively used in engineering structures and fatigue failure is one of the most common failure modes of metal structures. Fatigue phenomena occur when a material is subjected to fluctuating stresses and strains, which lead to failure due to damage accumulation. Different methods, including the Palmgren-Miner linear damage rule- (LDR-) based, multiaxial and variable amplitude loading, stochastic-based, energy-based, and continuum damage mechanics methods, forecast fatigue life. This paper reviews fatigue life prediction techniques for metallic materials. An ideal fatigue life prediction model should include the main features of those already established methods, and its implementation in simulation systems could help engineers and scientists in different applications. In conclusion, LDR-based, multiaxial and variable amplitude loading, stochastic-based, continuum damage mechanics, and energy-based methods are easy, realistic, microstructure dependent, well timed, and damage connected, respectively, for the ideal prediction model.

Identification of Variable Amplitude Fatigue Loading Based on Bivariate Probability Mass Functions

2019 ◽  
Author(s):  
Hewenxuan Li ◽  
David Chelidze
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Temporal Dynamics ◽  
Variable Amplitude ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Time Histories ◽  
Probability Mass ◽  
Bivariate Probability ◽  
Mass Functions

Abstract Fatigue life estimation under variable amplitude (VA) loading remains one of the major unresolved engineering problems. When engineering structures experience VA loading, the corresponding load at the crack front will be highly non-stationary. Under such conditions, the load interaction effects greatly affect fatigue crack propagation rate and can cause significant variation in the corresponding fatigue life. Existing characterization methods focus on single overload effect and their extensions to sequence of overloads which does not reflect the irregularity of the realistic loading. In this paper, numerical simulations were used to compare the fatigue life under various synthetic load time histories. The resulting time to failure estimation, concerning statistically and spectrally identical deterministic loads and their stochastic surrogates, exhibits drastic difference which reflects the corresponding differences in the temporal structure of the loads, which are not differentiated by their linear characteristics. This indicates that the temporal dynamics of the load time histories have considerable influence on fatigue crack propagation and fracture. In order to differentiate temporal dynamics of the synthetic loading, new bivariate probability mass functions (BPMFs) are proposed. They can capture and preserve the underlying temporal dynamics of locally non-stationary variable amplitude load-time histories with identical linear statistics. And qualitative explanations of the potential of this proposed method for fatigue life estimation under VA loading are discussed.

scholarly journals Influence of Selected Multiaxial Stress Paths on Fatigue Estimation under Variable Amplitude Loading

2021 ◽  
Author(s):  
Jan Papuga ◽  
Matúš Margetin ◽  
Vladimír Chmelko
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Multiaxial Loading ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Shift Effect ◽  
Fatigue Estimation

The paper discusses solutions used for estimating fatigue life under variable amplitude multiaxial loading in the high-cycle fatigue domain. Various concurring effects are treated, and their proposed solutions are commented upon. The focus is on the categories of the phase shift effect and of cycle counting. It is concluded that the available experimental data are not sufficient to substantiate a clear decision to follow a definite algorithm. An example of own new experimental data is provided, and the fatigue life estimation run to highlight some more points open for discussion.

An Experimental Investigation Into Fatigue Characterization of Oil Platform Risers Under Variable Amplitude Loading

2007 ◽  
Author(s):  
Mohammad Iranpour ◽  
Farid Taheri
Keyword(s):  
Fatigue Life ◽  
Time History ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Deep Waters ◽  
Fatigue Life Estimation ◽  
Induced Stresses ◽  
Offshore Industry ◽  
The Many

One of the many design challenges in offshore industry is the fatigue life estimation of risers due to the loading that is generated by vortex induced vibration (VIV). In deep waters, where the long risers are subjected to sever VIV-induced stresses and may encounter multi-modal vibration, the VIV-induced stresses could be the most significant contributor to the overall damage of the structure. The variable amplitude nature of the stress-time history often creates significant errors in the estimated fatigue life of the structure. The irregularities in the loading scenario could also create a considerable degree of plasticity at the crack tip, thus leading to. variability in material response. The uncertainties in the estimated fatigue damage under such a variable amplitude loading has resulted in the use of large safety factors by industry for establishing the fatigue life of the risers.

Predicting Fatigue Crack Growth and Fatigue Life Under Variable Amplitude Loading

2010 ◽  
Vol 2010 (2) ◽  
pp. 37-51
Author(s):  
Michal Jasztal ◽  
Dorota Kocanda ◽  
Henryk Tomaszek
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Probabilistic Approach ◽  
Alloy Sheet ◽  
Load Spectrum ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Fatigue Life Estimation

Predicting Fatigue Crack Growth and Fatigue Life Under Variable Amplitude Loading A probabilistic approach to the description of fatigue crack growth and fatigue life estimation of a component subjected to variable amplitude loading is presented in the paper. The core of the model is a differential equation originated from the Paris formula. In order to consider the influence of overload-underload cycles existing in an exploitive load spectrum on crack growth rate for an aeronautical aluminum alloy sheet, the modified Willenborg retardation model was applied.

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