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.

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 On the dependency of the parameters of fatigue crack growth from the fractal dimension of rough crack profiles

2013 ◽  
Vol 228 (12) ◽  
pp. 2059-2067 ◽  
Author(s):  
M Paggi ◽  
O Plekhov
Keyword(s):  
Fractal Dimension ◽  
Fatigue Crack ◽  
Quantitative Analysis ◽  
Crack Growth ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Crack Size ◽  
Fatigue Crack Propagation Rate ◽  
Paris Law ◽  
Growth Equations

A theoretical study based on dimensional analysis and fractal geometry of crack profiles is proposed to establish the relation between their fractal dimension D (1 <  D < 2) and the parameters defining the fatigue crack propagation rate. The exponent m of the Paris’ law is found to be an increasing function of the fractal dimension of the crack profile, m = 2 D/(2 −  D). This trend is confirmed by a quantitative analysis of fractographic images of titanium alloys with different grain sizes (different roughness of crack profiles), by a new experimental test and by an indirect estimation of D from crack growth equations accounting from crack-size effects in steel and aluminum. The present study can be considered as the first quantitative analysis of fractographic images aiming at relating the morphological features of cracks to their kinetics in fatigue.

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 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.

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