Prediction of Residual Fatigue Life of Bolts Based on Metal Magnetic Memory

2018 ◽  
Author(s):  
Changhang Xu ◽  
Jinxiu Cui
Keyword(s):  
Fatigue Life ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Residual Fatigue Life ◽  
Residual Fatigue

Integrity assessment and determination of residual fatigue life of vital parts of bucket-wheel excavator operating under dynamic loads

2019 ◽  
Vol 105 ◽  
pp. 182-195 ◽  
Author(s):  
Dušan Arsić ◽  
Nebojša Gnjatović ◽  
Simon Sedmak ◽  
Aleksandra Arsić ◽  
Milan Uhričik
Keyword(s):  
Fatigue Life ◽  
Dynamic Loads ◽  
Integrity Assessment ◽  
Residual Fatigue Life ◽  
Residual Fatigue

scholarly journals Effect of Pre-Corrosion Pits on Residual Fatigue Life for 42CrMo Steel

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2130 ◽  
Author(s):  
Dezheng Liu ◽  
Yan Li ◽  
Xiangdong Xie ◽  
Jing Zhao
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Research Work ◽  
Residual Fatigue Life ◽  
42Crmo Steel ◽  
Regression Formula ◽  
Residual Fatigue ◽  
Corrosion Pits

The effect of pre-corrosion pits on residual fatigue life for the 42CrMo steel (American grade: AISI 4140) is investigated using the accelerated pre-corrosion specimen in the saline environment. Different pre-corroded times are used for the specimens, and fatigue tests with different loads are then carried out on specimens. The pre-corrosion fatigue life is studied, and the fatigue fracture surfaces are examined by a surface profiler and a scanning electron microscope (SEM) to identify the crack nucleation sites and to determine the size and geometry of corrosion pits. Moreover, the stress intensity factor varying with corrosion pits in different size parameters is analyzed based on finite element (FE) software ABAQUS to derive the regression formula of the stress intensity factor. Subsequently, by integrating the regression formula with the Paris formula, the residual fatigue life is predicted and compared with experimental results, and the relationship of the stress intensity factor, pit depth, and residual fatigue life are given under different corrosion degrees. The fatigue life predicted by the coupled formula agrees well with experiment results. It is observed from the SEM images that higher stress amplitude and longer pre-corroded time can significantly decrease the residual fatigue life of the steel. Additionally, the research work has brought about the discovery that the rate of crack extension accelerates when the crack length increases. The research in this paper also demonstrates that the corrosion pit size can be used as a damage index to assess the residual fatigue life.

Effects of Variable Loading on Residual Fatigue Life of the Railway Wheelset

2013 ◽  
Vol 577-578 ◽  
pp. 121-124 ◽  
Author(s):  
Pavel Pokorný ◽  
Luboš Náhlík ◽  
M. Ševčík ◽  
Pavel Hutař
Keyword(s):  
Growth Rate ◽  
Fatigue Life ◽  
Life Time ◽  
Interaction Effects ◽  
Classical Approach ◽  
Variable Loading ◽  
Know How ◽  
Residual Fatigue Life ◽  
Residual Fatigue ◽  
Account Interaction

The paper deals with the effects of variable loading on residual fatigue life of the railway wheelset. The railway wheelsets can include some cracks created during manufacturing process or during previous operation. Therefore, it is important to know how the existing cracks will behave during further service of the train. The experiments show that the fatigue crack growth rate depends not only on size of the load amplitudes in a loading spectrum, but it depends also on the sequence of load amplitudes. Taking into account interaction effects of overloading cycles requires use a method that calculates increments of crack length in each cycle, i.e. cycle-by-cycle. One of such methods represents generalized Willenborg model. This model was used for residual fatigue life time estimations of railway wheelset and results obtained were compared with classical approach, which did not take into account interaction effects. Results obtained can be used for establishing of service intervals of railway wheelsets.

Effect of single and multiple overloading on the residual fatigue life of a structural steel

2003 ◽  
Vol 26 (2) ◽  
pp. 115-121 ◽  
Author(s):  
M. S. RAMOS ◽  
M. V. PEREIRA ◽  
F. A. DARWISH ◽  
S. H. MOTTA ◽  
M. A. CARNEIRO
Keyword(s):  
Fatigue Life ◽  
Structural Steel ◽  
Residual Fatigue Life ◽  
Residual Fatigue
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