scholarly journals A Review of the Loading Sequence Effects on the Fatigue Life Behaviour of Metallic Materials

2016 ◽  
Vol 9 (5) ◽  
pp. 189-200 ◽  
Author(s):  
K. A. Zakaria ◽  
◽  
S. Abdullah ◽  
M. J. Ghazali ◽  
◽  
...  
Keyword(s):  
Fatigue Life ◽  
Metallic Materials ◽  
Sequence Effects ◽  
Loading Sequence

scholarly journals Fatigue Design of Steel Bridge Deck Asphalt Pavement Based on Nonlinear Damage Accumulation Theory

2021 ◽  
Vol 11 (12) ◽  
pp. 5668
Author(s):  
Xunqian Xu ◽  
Yu Li ◽  
Wei Huang ◽  
Dakai Chen ◽  
Chen Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Bridge Deck ◽  
Asphalt Pavement ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Steel Bridge ◽  
Fatigue Design ◽  
Sequence Effects ◽  
Loading Sequence

Based on the nonlinear damage theory, this paper aims to explore the fatigue performance of steel bridge deck asphalt pavement under multistage fatigue load. Manson–Halford cumulative damage model and the modified model were introduced to describe loading sequence effects, and interactions between multiple loads were represented in stress ratio. The fatigue life prediction method of steel bridge deck asphalt pavement was put forward, considering loading sequence effects and load interactions. The fatigue design of steel bridge deck asphalt pavement was investigated with the fatigue life prediction model. The effects of different load levels and loading sequence on the fatigue design parameters stress ratio of steel bridge deck asphalt pavement were studied. The design results were compared with experimental results, and the prediction results were based on traditional Miner’s theory. The analysis results showed that the fatigue life prediction method based on the nonlinear cumulative damage theory can effectively design and analyze the fatigue characteristics of asphalt pavement of steel bridge deck with high accuracy and reliability. The fatigue life prediction model of steel bridge deck asphalt pavement can well reflect loading sequence effects and load interactions. In addition, the design model has relatively few parameters; therefore, it can be applied to practical engineering design.

A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

2006 ◽  
Vol 514-516 ◽  
pp. 804-809
Author(s):  
S. Gao ◽  
Ewald Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Die Material ◽  
Multi Level ◽  
Loading Sequence ◽  
Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

Fatigue Life Prediction for Variable Strain at a Mixing Tee by Use of Effective Strain Amplitude

2020 ◽  
Author(s):  
Koji Miyoshi ◽  
Masayuki Kamaya
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Hot Spot ◽  
Effective Strain ◽  
Single Overload ◽  
Loading Sequence

Abstract Mixing flow causes fluid temperature fluctuations near the pipe walls and may result in fatigue crack initiation. The authors have previously reported the loading sequence effect on thermal fatigue in a mixing tee. The fatigue damage around the hot spot, which was heated by the hot jet flow from the branch pipe, obtained by Miner’s rule was less than 1.0. Since the strain around the hot spot had waveforms with periodic overload, the loading sequence with periodic overload caused reduction of the fatigue life around the hot spot. In this study, the effect of a single overload on the fatigue crack growth rate was investigated in order to clarify the reduction of the fatigue life at the mixing tee due to strain with periodic overload. In addition, the prediction method of the fatigue life for the variable thermal strain at the mixing tee was discussed. It was shown the crack growth rate increased after an overload for both cases of tensile and compressive overloads. The effective strain amplitude increased after the application of a single overload. The fatigue life curve was modified by considering the increment of the effective strain range. The fatigue damage recalculated using the modified fatigue life curve was larger than 1.0 except in a few cases. The fatigue life could be assessed conservatively for variable strain at the mixing tee using the developed fatigue curve and Miner’s rule.

Loading sequence effects on dragload and downdrag for pile foundation

2010 ◽  
Vol 16 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Gangqiang Kong ◽  
Qing Yang ◽  
Maotian Luan
Keyword(s):  
Pile Foundation ◽  
Sequence Effects ◽  
Loading 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.

The Effect of Manufacturing Defects on the Fatigue Behaviour of Ti-6Al-4V Specimens Fabricated Using Selective Laser Melting

2014 ◽  
Vol 891-892 ◽  
pp. 1519-1524 ◽  
Author(s):  
Qian Chu Liu ◽  
Joe Elambasseril ◽  
Shou Jin Sun ◽  
Martin Leary ◽  
Milan Brandt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Selective Laser Melting ◽  
Fatigue Crack Initiation ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Metallic Materials ◽  
Laser Melting ◽  
Manufacturing Defects ◽  
Materials Properties

Additive Manufacturing (AM) technologies are considered revolutionary because they could fundamentally change the way products are designed. Selective Laser Melting (SLM) is a metal based AM process with significant and growing potential for the manufacture of aerospace components. Traditionally a material needs to be listed in the Metallic Materials Properties Development and Standardization (MMPDS) handbook if it is to be considered certified. However, this requires a considerable amount of test data to be generated on the materials mechanical properties. Therefore, the MMPDS certification process does not lend itself easily to the certification of AM components as the final component can have similar mechanical properties to wrought alloys combined with the defects associated with traditional casting and welding technologies. These defects can substantially decrease the fatigue life of a fabricated component. The primary purpose of this investigation was to study the fatigue behaviour of as-built Ti-6Al-4V (Ti64) samples. Fatigue tests were performed on the Ti-6Al-4V specimens built using SLM with a variety of layer thicknesses and build (vertical or horizontal) directions. Fractography revealed the presence of a range of manufacturing defects located at or near the surface of the specimens. The experimental results indicated that Lack-of-Fusion (LOF) defects were primarily responsible for fatigue crack initiation. The reduction in fatigue life appeared to be affected by the location, size and shape of the LOF defect.

Sign in / Sign up

Export Citation Format

Share Document