Low-cycle fatigue of steel structures. An experimental investigation with full scale ship structural components 12

The combined high and low cycle fatigue (CCF) test on full scale turbine blade in the laboratory is an important method to evaluate the life. In fact, the low cycle fatigue which is usually caused by the centrifugal force can be confirmed easily. While, the high cycle fatigue which is usually caused by the vibration and aerodynamic force is often hard to determine. So the previous scholar has proposed the contrast method to determine the high cycle load in the field. This method utilizes the new and used blades to determine the high cycle within certain limits. While it can’t be applied effectively in the whole life range with the low cycle-high cycle-ultra high cycle fatigue theory raised. So this paper put forward the modified contrast method to realize the optimization. Firstly, the CCF tests are carried out on the turbine blade systematically. Then, the CCF damage properties, including the crack propagation, the fracture morphology and the dynamic characteristic are analyzed. Lastly, the new modified contrast method is proposed with the new coordinate axes, new fitting criterions and amend method. Through comparisons we conclude that: the new method is slightly complicated, but the evaluate precision has significantly increased. So it could be used to deal with data for CCF tests on full scale turbine blade in the future.

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Experimental Investigation on the Low Cycle Fatigue Life of Piles

Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges ◽

10.1201/9781315189390-366 ◽

2018 ◽

pp. 2703-2708

Author(s):

M. Karalar ◽

M. Dicleli

Keyword(s):

Experimental Investigation ◽

Fatigue Life ◽

Low Cycle Fatigue ◽

Cycle Fatigue

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Multiaxial fatigue life estimation in low-cycle fatigue regime including the mean stress effect

MATEC Web of Conferences ◽

10.1051/matecconf/201816516002 ◽

2018 ◽

Vol 165 ◽

pp. 16002

Author(s):

Daniela Scorza ◽

Andrea Carpinteri ◽

Giovanni Fortese ◽

Camilla Ronchei ◽

Sabrina Vantadori ◽

...

Keyword(s):

Fatigue Life ◽

Low Cycle Fatigue ◽

Equivalent Strain ◽

Mean Value ◽

Multiaxial Fatigue ◽

Stress Effect ◽

Mean Stress ◽

Cycle Fatigue ◽

Structural Components ◽

Mean Stress Effect

The goal of the present paper is to discuss the reliability of a strain-based multiaxial Low-Cycle Fatigue (LCF) criterion in estimating the fatigue lifetime of metallic structural components subjected to multiaxial sinusoidal loading with zero and non-zero mean value. Since it is well-known that a tensile mean normal stress reduces the fatigue life of structural components, three different models available in the literature are implemented in the present criterion in order to take into account the above mean stress effect. In particular, such a criterion is formulated in terms of strains by employing the displacement components acting on the critical plane and, then, by defining an equivalent strain related to such a plane. The Morrow model, the Smith-Watson-Topper model and the Manson-Halford model are applied to define such an equivalent strain. The effectiveness of the new formulations is evaluated through comparison with some experimental data reported in the literature, related to biaxial fatigue tests performed on metallic specimens under in-and out-of-phase loadings characterised by non-zero mean stress values.

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