scholarly journals Numerical Modeling of Plasticity-Induced Fatigue Crack Growth Retardation Due to Deflection in the Near-Tip Area

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 541
Author(s):  
Jesús Toribio ◽  
Juan-Carlos Matos ◽  
Beatriz González
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Retardation Effect ◽  
Fatigue Crack Propagation Rate ◽  
Kinked Crack ◽  
Number Of Cycles

This article studies the retardation effect in plasticity-induced fatigue crack growth rate for a low-medium strength steel, due to the appearance of microdeflections in the crack path. To this end, the finite element method was used to model the crack with its kinked tip under several stress intensity factor (SIF) ranges. The results allowed a calculation (after a small number of cycles) of the fatigue crack propagation rate for the multiaxial and uniaxial fatigue configurations at the microscopic level. It was observed that the retardation effect rose with an increase in the initial kinked crack tip angle, an increase in the initial projected kinked crack tip length, and with a decrease in the SIF range.

Fatigue Crack Propagation Rate in EUROFER 97 Estimated Using Small Specimens

2010 ◽  
Vol 452-453 ◽  
pp. 325-328 ◽  
Author(s):  
Pavel Hutař ◽  
Luboš Náhlík ◽  
Martin Ševčík ◽  
Stanislav Seitl ◽  
Tomáš Kruml ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Propagation Rate ◽  
Fatigue Curve ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Growth Data ◽  
Element Analysis ◽  
Eurofer 97

The proposed paper describes fatigue damage evolution in Eurofer 97 reduced activation ferritic-martensitic steel. The short crack growth study was performed on small cylindrical specimens using an MTS 880 servohydraulic machine at constant strain amplitude. Based on the fatigue crack growth data obtained and corresponding 3D finite element analysis Paris law region of the fatigue curve were estimated. The results obtained were compared with standard determination of the fatigue crack growth rate according to ASTM using CT specimens. The presented results can help to transfer experimental data measured on small specimens to large structures and vice versa.

Effect of the Fracture Toughness of Materials (Kc) on Fatigue Crack Propagation Rate

2012 ◽  
Vol 594-597 ◽  
pp. 1005-1008 ◽  
Author(s):  
Li Xiong Gu ◽  
Zhong Yong Xu ◽  
Zhi Fang Liu
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Test Results

In this paper, the fracture toughness of materials, , effects on fatigue crack propagation that can be quantified using the dynamical coefficient mechanics (DCM) model. And we can not only change the material with high value, but also should take other methods into consideration to decrease the fatigue crack growth (FCG) rate when replacing material can’t obviously decrease the FCG rate, which were examined objectively by the test results from literature.

scholarly journals A Model for Fatigue Crack Growth in the Paris Regime under the Variability of Cyclic Hardening and Elastic Properties

2017 ◽  
Vol 2017 (9) ◽  
pp. 117-135
Author(s):  
Tayeb Kebir ◽  
Mohamed Benguediab ◽  
Abdellatif Imad
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Propagation Rate ◽  
Cyclic Hardening ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Paris Law ◽  
Final Failure ◽  
Cyclic Plastic Deformation

AbstractOver the last 60 years, several models have been developed governing different zones of fatigue crack growth from the threshold zone to final failure. The best known model is the Paris law and a number of its based on mechanical, metallurgical and loading parameters governing the propagation of cracks. This paper presents an analytical model developed to predict the fatigue crack propagation rate in the Paris regime, for different material properties, yield strength (σy), Young’s modulus (E) and cyclic hardening parameters (K’, n’) and their influence by variability. The cyclic plastic deformation at a crack tip or any other cyclic hardening rule may be used to reach this objective, for to investigate this influence, these properties of the model are calibrated using available experimental data in the literature. This FCGR model was validated on Al-alloys specimens under constant amplitude load and shows good agreement with the experimental results.

Effect of Constraint on Fatigue Crack Propagation in Notched Plates

2010 ◽  
Author(s):  
Xin Wang
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Rate Model ◽  
Propagation Law ◽  
Crack Tip Constraint

It has been observed that the loss of crack tip constraint leads to enhanced resistance to both cleavage and ductile tearing. Recent developments on constraint-based fracture mechanics have enabled the practical assessment of defective components including the constraint effect. In fatigue analyses, it is common practice to use the Paris crack propagation law, which is based on the stress intensity factor alone. Although in recent years several research attempts have been made to investigate the effect of constraint on fatigue, how to quantify the effect of crack tip constraint on the fatigue crack propagation rate is still an open issue. In this paper, the effect of crack tip constraint on the fatigue crack propagation of small cracks at notched plates is investigated. A fatigue crack propagation rate model developed earlier which incorporates both low and high constraint conditions is used. It is shown that the effect of constraint on crack propagation rate is significant when the crack is small (within the stress concentration of the notches). This effect can be accounted for by using the fatigue crack propagation rate model.

FATIGUE CRACK GROWTH BEHAVIOR OF STAINLESS STEEL COATED WITH TiN FILM

2012 ◽  
Vol 06 ◽  
pp. 282-287
Author(s):  
SATOSHI FUKUI ◽  
DAISUKE YONEKURA ◽  
RI-ICHI MURAKAMI
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Crack Growth Behavior ◽  
Tin Film

In our previous study, we examined the influence of the fatigue properties of the stainless steel coated with TiN film and clarified the influence of TiN coating and the surface roughness on the fatigue property. In this study, the four point bending fatigue crack growth tests were carried out for martensitic stainless steel coated with TiN film deposited by arc ion plating method in order to investigate the effect of surface finishing on the fatigue crack behavior for film coated material. The fatigue crack growth behavior was evaluated using the replica method. As a result, the crack propagation rate of mirror polished specimens were lower than that of rough surface specimens. The crack propagation rate was especially decreased for TiN coatings deposited on the mirror polished substrate. The surface roughness near the crack initiation site increased after fatigue test. It concludes that the surface roughness of substrate influences crack propagation rate and the deposition of TiN film affected influenced crack propagation rate and fatigue strength when the surface roughness of substrate is small enough.

The Characteristics of Propagation for Mixed-Mode Fatigue Crack under Stress Re-Distribution at Fatigue Crack Tip

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1922-1927 ◽  
Author(s):  
Sam Hong Song ◽  
Jeong Moo Lee
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Mixed Mode ◽  
Applied Load ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Stress Redistribution ◽  
Fatigue Crack Propagation Rate

The practical condition of applied load represents mixed-mode loading condition due to complications of element geometry and applied load. Also, the characteristics of fatigue crack propagation under mixed mode were affected by constrained shape of structures and applied load variation. There are continuous variations of stress condition at crack tip on the fatigue crack during propagation. Therefore, it is necessary to investigate the propagation behavior of mixed-mode fatigue crack under stress redistribution condition. We established the experimental method in order to form the stress redistribution condition. It is assumed that the stress around the crack tip under mixed-mode fatigue loading is redistributed. This test consisted of the 1st and the 2nd round of tests. The stress re distribution was formed by changing the loading direction at propagating mixed-mode fatigue crack tip. In this study, the behavior of mixed-mode fatigue crack affected by stress redistribution was investigated by comparing fatigue crack propagation rate, fatigue crack propagation paths and fatigue crack branch angle. From the experiment, as loading application angle and thickness change, the fatigue crack propagation rate and angle under mixed mode were affected by stress redistribution.

Effect of Constraint on Fatigue Crack Propagation in T-Plate Welded Joints

2007 ◽  
Author(s):  
Xin Wang ◽  
Qing Gao
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Welded Joints ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Rate Model ◽  
Crack Tip Constraint

It has been observed that the loss of crack tip constraint leads to enhanced resistance to both cleavage and ductile tearing. Recent developments on constraint-based fracture mechanics have enabled the practical assessment of defective components including the constraint effect. However, how to quantify the effect of crack tip constraint on the fatigue crack propagation rate is still an open issue. It is common practice to use the Paris crack propagation law, which is based on the stress intensity factor alone. In this paper, the effect of crack tip constraint on the fatigue crack propagation of small cracks at T-plate welded joints is investigated. A fatigue crack propagation rate model is developed incorporating both low and high constraint conditions. It is shown that the effect of constraint on crack propagation rate is significant when the crack is small (within the stress concentration of the weld joints). This effect can be accounted for by using the proposed fatigue crack propagation rate model.

Finite Element Analysis of the Influence of Crack Tip Stress Distributionon Fatigue Crack Propagation Rate of 5XXX Aluminum Alloy

2015 ◽  
Vol 817 ◽  
pp. 698-705 ◽  
Author(s):  
Jia Ju Liu ◽  
Hui Huang ◽  
Ran Liu ◽  
Li Rong ◽  
Wei Wang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Intensity Factors ◽  
Paris Region ◽  
Crack Tip Stress

5XXX aircraft skin aluminum alloy needs relatively high fatigue performance to sustain complex pneumatic loading in service. Stress intensity factors are important parameters to compute fatigue crack propagation rate. XFEM was used to calculate the crack tip stress, as well as stress intensity factors (SIF) and fatigue crack propagation rate on the 5E62 alloy. Simulation results showed that the values of SIF calculated by XFEM were quite close to the theoretical values. Both the values of crack tip stress and SIF increase as crack length increasing in Paris region, resulting the increasing of fatigue crack growth rate. Fatigue crack propagation rate calculated by XFEM are consistent with the theoretical values and experimental values in Paris region.

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