Dissipated energy based fatigue crack propagation law for complex loading conditions

2011 ◽

Vol 110-116 ◽

pp. 29-32

Author(s):

Guo Bin Zhang ◽

Huang Yuan

Keyword(s):

Fatigue Crack ◽

Elevated Temperature ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Damage Model ◽

Complex Loading ◽

Creep Damage ◽

Loading Conditions ◽

Creep Fatigue ◽

Creep Damage Model

Creep damage is an important failure factor of high-temperature alloy. The fatigue crack growth under elevated temperature of the material is investigated for life prediction. In this paper, the numerical simulation of the crack propagation in nickel-based super alloy, IN718, was presented. A modified creep damage model was employed to accumulate the creep damage under cyclic loading conditions. The numerical results exhibit a reasonable agreement in the comparison with the experimental data. The cohesive zone approach, combining with the extended finite element method, has the ability to simulate the creep-fatigue crack propagation even for more complex loading conditions and specimen geometries.

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Description of Small Fatigue Crack Propagation in ODS Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.911 ◽

2014 ◽

Vol 891-892 ◽

pp. 911-916

Author(s):

Pavel Hutař ◽

Ivo Kuběna ◽

Miroslav Šmíd ◽

Martin Ševčík ◽

Tomáš Kruml ◽

...

Keyword(s):

Fatigue Crack ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

High Stress ◽

Oxide Dispersion Strengthened ◽

Ods Steel ◽

Small Fatigue Crack ◽

Propagation Law

The oxide dispersion strengthened (ODS) steels are widely studied as possible candidate material for fission and fusion technology. Due to application of the ODS materials, mainly low cycle fatigue is important. Therefore, small crack initiation and propagation for rather high stress amplitude are in focus. The main aim of the presented work is description of the small fatigue crack propagation for ODS-EUROFER steel. Due to limited quantity of ODS steel special miniaturized cylindrical specimens for fatigue testing were designed. Crack propagation law based on plastic part of J-integral is presented and applied for mentioned material. The resulting fatigue crack propagation rates for ODS-EUROFER steel and EUROFER 97 are compared and discussed.

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FATIGUE CRACK PROPAGATION AND CRACK CLOSURE BEHAVIOUR UNDER VARYING LOADING CONDITIONS

Advances in Research on the Strength and Fracture of Materials ◽

10.1016/b978-0-08-022140-3.50064-1 ◽

1978 ◽

pp. 1109-1116

Author(s):

Makoto Kikukawa ◽

Masahiro Jono ◽

Ken-ichi Tanaka ◽

Yoshiyuki Kondo

Keyword(s):

Fatigue Crack ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Crack Closure ◽

Loading Conditions

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Effect of Constraint on Fatigue Crack Propagation in Notched Plates

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 6 ◽

10.1115/omae2010-20903 ◽

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.

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