Fretting High-Cycle Fatigue Assessment through a Multiaxial Critical Plane-Based Criterion in Conjunction with the Taylor’s Point Method

2016 ◽  
Vol 258 ◽  
pp. 217-220 ◽  
Author(s):  
Camilla Ronchei ◽  
Andrea Carpinteri ◽  
Giovanni Fortese ◽  
Daniela Scorza ◽  
Sabrina Vantadori

The critical plane-based multiaxial criterion originally proposed by the authors for plain fatigue is here applied to estimate the crack initiation life of fretting high-cycle fatigued structural components. Although fretting fatigue can be regarded as a case of multiaxial fatigue, the common multiaxial fatigue criteria have to be modified to account for the severe stress gradients in the contact zone. Therefore, the above criterion is used in conjunction with the Taylor’s point method to numerically estimate the fatigue life of Ti-6Al-4V and Al-4Cu specimens under cylindrical contacts.

2018 ◽  
Vol 165 ◽  
pp. 16002
Author(s):  
Daniela Scorza ◽  
Andrea Carpinteri ◽  
Giovanni Fortese ◽  
Camilla Ronchei ◽  
Sabrina Vantadori ◽  
...  

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.


2013 ◽  
Vol 211 ◽  
pp. 83-88
Author(s):  
Marek Cieśla

Usefulness of the magnesium alloys for construction of structural components is determined, apart from their low density, by a number of favourable mechanical properties and in the case of their use for components of transport means additionally by good fatigue strength. In this study, 12 mm diameter extruded rods of AZ31 and AZ61 magnesium alloys were used as test material. After extrusion the rods were annealed at a temperature of 400°C, with a 60 min soaking period and subsequent cooling in air. Cylindrical specimens with a diameter of d0 = 8 mm were made for the fatigue test under high-cycle rotary bending conditions with the cycle asymmetry coefficient R = -1. The tests were carried out for a limited fatigue strength range. Examination of microstructure of tested alloys and fatigue fractography were also performed. During the high-cycle fatigue tests it was found that the AZ61 alloy has a longer fatigue life. Based on the obtained results, fatigue life characteristics of the tested materials were drawn up.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1060 ◽  
Author(s):  
Alejandro Cruces ◽  
Pablo Lopez-Crespo ◽  
Belen Moreno ◽  
Fernando Antunes

This work analyses the prediction capabilities of a recently developed critical plane model, called the SKS method. The study uses multiaxial fatigue data for S355-J2G3 steel, with in-phase and 90° out-of-phase sinusoidal axial-torsional straining in both the low cycle fatigue and high cycle fatigue ranges. The SKS damage parameter includes the effect of hardening, mean shear stress and the interaction between shear and normal stress on the critical plane. The collapse and the prediction capabilities of the SKS critical plane damage parameter are compared to well-established critical plane models, namely Wang-Brown, Fatemi-Socie, Liu I and Liu II models. The differences between models are discussed in detail from the basis of the methodology and the life results. The collapse capacity of the SKS damage parameter presents the best results. The SKS model produced the second-best results for the different types of multiaxial loads studied.


2018 ◽  
Vol 774 ◽  
pp. 504-509
Author(s):  
A.S. Cruces ◽  
Pablo Lopez-Crespo ◽  
S. Sandip ◽  
Belen Moreno

The present work assesses the fatigue life prediction capability of a recently proposed critical plane model. For this study, multiaxial fatigue data of S355-J2G3 steel were used; in-phase and 90o out-of-phase sinusoidal axial-torsional straining from 103 to 106 cycles, so it was possible to evaluate the model at low and high cycle fatigue, as well as the hardening effect. The damage parameters considered in this paper include the effect of hardening, mean shear stress effect and the effect due to interaction of shear and normal stress on the critical plane. A comparative evaluation of well accepted models (Wang-Brown, Fatemi-Socie and Liu 1 and 2) with the new recently proposed model (Suman-Kallmeyer) is done. The ability of the different models to predict the fatigue life for large and diverse load data set are discussed.


Author(s):  
Cao Chen ◽  
Xiaojun Yan ◽  
Xiaoyong Zhang ◽  
Yingsong Zhang ◽  
Min Gui ◽  
...  

Some cracks were detected on the fir-tree root of turbine blade in an in-service aero-engine, and the aluminized coating was considered to be the main cause of these cracks. To study the effect of aluminized coating on fatigue life of turbine blade, the combined low and high cycle fatigue (CCF) tests are carried out at elevated temperature on both aluminized and untreated turbine blades. Probability analysis of test data is conducted and the result indicates that the median life is decreased by 62.2% due to the effect of the aluminized coating. Further study on the mechanism of crack initiation and propagation has been conducted based on fractography and cross section morphology analysis by using scanning electron microscope (SEM), and the results indicate: (1) The aluminized coating consists of two layers, of which the inner layer is considered to contain the σ phase and it reduces the resistance to fatigue of blade. (2) Many cavities are found in the inner layer of aluminized coating, which lead to the initiation of cracks and result in the reduction of crack initiation life. (3) The marker band widths of aluminized and untreated blade are very close, which indicated the aluminized coating may have no effect on the crack propagation life of the blade.


2016 ◽  
Vol 250 ◽  
pp. 157-162
Author(s):  
Lukasz Pejkowski ◽  
Dariusz Skibicki ◽  
Mateusz Wirwicki

High–cycle multiaxial fatigue tests under proportional and non-proportional loading conditions with various combinations of superimposed static mean stresses was carried out on Cu-ETP copper. The results show differences in fatigue life between various ratios of mean stresses. These results are similar to others described in the literature.


2016 ◽  
Vol 27 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Jia-Liang Zhang ◽  
De-Guang Shang ◽  
Yu-Juan Sun ◽  
Xiao-Wei Wang

The aim of this paper is to propose a modified multiaxial high-cycle fatigue criterion based on the critical plane approach. The proposed criterion contains three parameters, that is, shear stress amplitude, normal stress amplitude and mean normal stress. In order to take into account the mean shear stress effects, the critical plane is determined by the maximum shear stress. In the proposed multiaxial fatigue criterion, the influence of mean normal stress on fatigue damage is also considered. Based on the proposed criterion, the multiaxial fatigue life is predicted, and the results showed a good agreement with experimental data obtained from some literatures.


2005 ◽  
Vol 297-300 ◽  
pp. 22-27
Author(s):  
Tae Wan Kim ◽  
Sang Don Lee ◽  
Yong Joo Cho

In this study, the simulation of contact fatigue based on stress analysis is conducted under Elastohydrodynamic Lubrication (EHL) state. To predict a crack initiation life accurately, it is necessary to calculate contact stress and subsurface stresses accurately. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions and the subsurface stress is obtained using rectangular patch solutions. The numerical algorithm using newton-rapson method was constructed to calculate the EHL pressure. Based on these stress values, three multiaxial high-cycle fatigue criteria are used. As a result, the effects of EHL on contact fatigue life are calculated.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 445
Author(s):  
Tomoyuki Fujii ◽  
Muhamad Safwan Bin Muhamad Azmi ◽  
Keiichiro Tohgo ◽  
Yoshinobu Shimamura

This paper discusses how the strain gradient influences the fatigue life of carbon steel in the low-cycle and high-cycle fatigue regimes. To obtain fatigue data under different strain distributions, cyclic alternating bending tests using specimens with different thicknesses and cyclic tension–compression tests were conducted on carbon steel for pressure vessels (SPV235). The crack initiation life and total failure life were evaluated via the strain-based approach. The experimental results showed that the crack initiation life became short with decreasing strain gradient from 102 to 106 cycles in fatigue life. On the other hand, the influence of the strain gradient on the total failure life was different from that on the crack initiation life: although the total failure life of the specimen subjected to cyclic tension–compression was also the shortest, the strain gradient did not affect the total failure life of the specimen subjected to cyclic bending from 102 to 106 cycles in fatigue life. This was because the crack propagation life became longer in a thicker specimen. Hence, these experimental results implied that the fatigue crack initiation life could be characterized by not only strain but also the strain gradient in the low-cycle and high-cycle fatigue regimes.


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