Multi-Axial Fatigue and Fracture Behavior in Metals

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Metal Failure Analysis".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 12242

Special Issue Editor


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Guest Editor
IDMEC, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Interests: fatigue; multiaxial fatigue; very high cycle fatigue; mixed-mode fracture
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Special Issue Information

Dear Colleagues,

The continuous study of material fatigue and the development of new testing devices and methods for its characterization prove its importance, not only in scientific terms but also in its practical application. With the development of new materials and alloys, there is an increasing demand for materials which are reliable, can be obtained in a timely manner, and possess predictable properties. Through detailed characterization, more complex designs with reduced weight improvement and longer lifespans can be created and achieved with increased reliability, confidence, and safety.

Fatigue tests were initially predominantly focused on inducing uniaxial loads. However, since most components and machines are subjected to multiaxial cyclic loads, many researchers have dedicated their studies to multiaxial loading and these technological developments are associated with the materials’ fatigue characteristics and properties.

As fatigue multiaxial inducing technics have increased in reliability and versatility, tailored towards the material and shape under analysis, the same can be said of the testing cyclic frequency. Fatigue failure was once thought to be limited to 10E7 cycles (the fatigue limit) and it was assumed that no failure would occur, i.e., materials would have an infinite lifespan, beyond the fatigue limit. Nevertheless, later research suggested that the problem of fatigue failure could still be overcome. Thereafter, failure occurring beyond the believed fatigue limit was established to be within the very high cycle fatigue (VHCF) regime, between 10E7 and 10E10 cycles.

Conventional fatigue testing machines have operational frequencies that typically range between 20 and 150 Hz. This means that it is not feasible to use these machines to test materials up to the VHCF regime and achieve reliable fatigue characterization for such a considerable number of cycles in a practical amount of time. With the aim of inducing fatigue damage in higher fatigue frequency regimes, new testing methods have been proposed, namely ultrasonic fatigue testing (UFT) either in uniaxial or biaxial loadings, including tension/torsion or in-plane bi-axial loadings.

Prof. Dr. Manuel Freitas
Guest Editor

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Keywords

  • fatigue
  • notches
  • critical distance
  • multiaxial fatigue
  • tension/torsion loading
  • bi-axial loading
  • cruciform specimens
  • very high cycle fatigue
  • uniaxial and biaxial VHCF
  • mixed-mode fracture
  • failure analysis

Published Papers (5 papers)

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Research

12 pages, 3210 KiB  
Article
Fracture Kinetics and Mechanisms of Ultrafine-Grained Materials during Fatigue Tests in the Low-Cycle Fatigue Region
by Gennadiy V. Klevtsov, Ruslan Z. Valiev, Natal’ya A. Klevtsova, Maksim N. Tyurkov, Irina N. Pigaleva and Denis A. Aksenov
Metals 2023, 13(4), 709; https://doi.org/10.3390/met13040709 - 4 Apr 2023
Viewed by 1230
Abstract
In this paper, the fracture kinetics and mechanisms in the low-cycle fatigue region were analyzed for different ultrafine-grained (UFG) materials with body-centered cubic (bcc), hexagonal close-packed (hcp) and face-centered cubic (fcc) lattices. Three-point bending principle fatigue tests were performed. The tests show that [...] Read more.
In this paper, the fracture kinetics and mechanisms in the low-cycle fatigue region were analyzed for different ultrafine-grained (UFG) materials with body-centered cubic (bcc), hexagonal close-packed (hcp) and face-centered cubic (fcc) lattices. Three-point bending principle fatigue tests were performed. The tests show that the UFG structure formation in the investigated materials has an ambiguous effect on the total number of cycles to failure (life) of the samples. The number of cycles to fatigue crack initiation (Nin) is about 20% of the total life of the samples, irrespective of the material state and the crystal lattice type. At the same value of the stress intensity coefficient range (∆K), for the majority of the investigated UFG materials, the fatigue crack propagation rate (dl/dN) is close to or lower than that of the initial coarse-grained (CG) materials. For the UFG materials, the coefficient n in the Paris equation is, in most cases, lower than that for the CG materials, which indicates that the UFG materials are less sensitive to cyclic overload. The fatigue fracture mechanisms of the investigated CG and UFG materials are rather similar, although the fracture of the UFG materials is accompanied by the formation of many secondary cracks, irrespective of the crystal lattice type. Full article
(This article belongs to the Special Issue Multi-Axial Fatigue and Fracture Behavior in Metals)
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13 pages, 5143 KiB  
Article
Failure Analysis of Bank-Wall Side Boiler Tube in a Petrochemical Plant
by Husaini Ardy, Asep Nurimam, Mohammad Hamdani, Deny Firmansyah, Dominico Michael Aditya, Asep Ridwan Setiawan and Arie Wibowo
Metals 2022, 12(12), 2064; https://doi.org/10.3390/met12122064 - 30 Nov 2022
Cited by 3 | Viewed by 4424
Abstract
Failure analysis of the petrochemical plant’s bank-wall side boiler tube has been conducted to determine the root cause of tube failure. The tube material is low carbon steel ASTM A178 grade A. Visual examinations of the cracked surface revealed that the fractured surface [...] Read more.
Failure analysis of the petrochemical plant’s bank-wall side boiler tube has been conducted to determine the root cause of tube failure. The tube material is low carbon steel ASTM A178 grade A. Visual examinations of the cracked surface revealed that the fractured surface is flat, without plastic deformation, and several longitudinal and transverse fissures are present. The SEM and optical microscope examinations show that the cracks were intergranular and transgranular. A hydrogen attack caused the intergranular crack, and thermal fatigue produced the transgranular crack. Boiler tube failure was caused by a steam blanket on the sloping tube’s top inner diameter that induced iron oxide deposition and accumulation. Hydrogen was produced after a chemical reaction at the deposit-metal interface between the iron oxide deposit and ingress steam. Local temperature variation on the top part of the sloped tube occurred during the splashing and evaporation of water, promoting thermal fatigue. Full article
(This article belongs to the Special Issue Multi-Axial Fatigue and Fracture Behavior in Metals)
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21 pages, 40780 KiB  
Article
Effect of Microstructure on High Cycle Fatigue Behavior of 211Z.X-T6 Aluminum Alloy
by Zhong Zhang, Chaowen Huang, Sinuo Chen, Mingpan Wan, Ming Yang, Shengli Ji and Weidong Zeng
Metals 2022, 12(3), 387; https://doi.org/10.3390/met12030387 - 23 Feb 2022
Cited by 3 | Viewed by 2003
Abstract
In the present paper, the high cycle fatigue (HCF) of a novel 211Z.X aluminum alloy with high strength was studied under hot-rolling and as-cast states at room temperature. The effects of microstructure and distribution of precipitated phases and impurities on the mechanical properties, [...] Read more.
In the present paper, the high cycle fatigue (HCF) of a novel 211Z.X aluminum alloy with high strength was studied under hot-rolling and as-cast states at room temperature. The effects of microstructure and distribution of precipitated phases and impurities on the mechanical properties, HCF performances, fatigue microcrack initiation, and propagation behavior of the 211Z.X alloy were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The HCF S–N curves, P–S–N curves and Goodman fatigue diagrams of 211Z.X alloy consisting of two microstructures were drawn. The results suggested that the fine and dispersive distribution of the second phases improved the strength of the alloy. The formation of short-bar and spherical precipitates promoted coordinated deformation of the alloy. This promoted higher microcrack initiation resistance of 211Z.X alloy with a hot rolling state than in the cast state. As a result, the HCF properties of the hot-rolling alloy were better than those of the cast alloy. In sum, these results look promising for future reliable design of engineering structures and application of new aluminum alloys. Full article
(This article belongs to the Special Issue Multi-Axial Fatigue and Fracture Behavior in Metals)
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14 pages, 2241 KiB  
Article
Effect of Shear/Axial Stress Ratio on Multiaxial Non-Proportional Loading Fatigue Damage on AISI 303 Steel
by Vitor Anes, Luis Reis and Manuel Freitas
Metals 2022, 12(1), 89; https://doi.org/10.3390/met12010089 - 4 Jan 2022
Cited by 4 | Viewed by 1537
Abstract
In this paper, we investigate the cyclic response of AISI 303 stainless steel subjected to non-proportional loads with different amplitude ratios between shear stresses and normal stresses. Based on the experiments, a relationship between the proportional reference load and a varied range of [...] Read more.
In this paper, we investigate the cyclic response of AISI 303 stainless steel subjected to non-proportional loads with different amplitude ratios between shear stresses and normal stresses. Based on the experiments, a relationship between the proportional reference load and a varied range of non-proportional loads was established. To achieve this objective, an experimental program was implemented to evaluate the non-proportional parameter Y. Then, the evolution of this parameter was analyzed with the number of cycles to failure and with the ratio between shear and normal stresses, finally, the evolution of the non-proportional parameter Y was mapped by two functions. The results show that the non-proportional response of the AISI 303 can be estimated using the two functions obtained. This allows the estimation of the relationship between non-proportional and proportional stresses as a function of the number of cycles to failure together with the relationship between shear and normal stresses. The results obtained have direct application in the evaluation of accumulated damage, assessed in real-time, resulting from variable amplitude loading spectra. This is of particular interest for the evaluation of structural health monitoring of structures and mechanical components. Full article
(This article belongs to the Special Issue Multi-Axial Fatigue and Fracture Behavior in Metals)
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23 pages, 10023 KiB  
Article
Numerical Study on Vibration Response and Fatigue Damage of Axial Compressor Blade Considering Aerodynamic Excitation
by Xi Fu, Chao Ma, Jiewei Lin and Junhong Zhang
Metals 2021, 11(11), 1835; https://doi.org/10.3390/met11111835 - 15 Nov 2021
Cited by 7 | Viewed by 2120
Abstract
Axial compressor blades with a deformed initial torsion angle caused by aerodynamic excitation resonated at the working speed and changed the rule of fatigue damage accumulation. The fatigue life of a blade has a prediction error, even causing serious flight accidents if the [...] Read more.
Axial compressor blades with a deformed initial torsion angle caused by aerodynamic excitation resonated at the working speed and changed the rule of fatigue damage accumulation. The fatigue life of a blade has a prediction error, even causing serious flight accidents if the effect of torque causing damage deterioration of the blade fatigue life is neglected. Therefore, in this paper, a uniaxial non-linear fatigue damage model was modified using the equivalent stress with torsional shear stress, and the proposed fatigue model including the torsional moment was used to study the compressor blade fatigue life. Then, the blade numerical simulation model was established to calculate the vibration characteristics under complex loads of airflow excitation and a rotating centrifugal force. Finally, the blade fatigue life under actual working conditions was predicted using the modified fatigue model. The results show that the interaction between centrifugal and aerodynamic loads affects the natural frequency, as the frequencies in modes dominated by bending deformation decreased whereas those dominated by torsional deformation increased. Furthermore, the blade root of the suction surface showed stress concentration, but there is an obvious difference of stress distribution and amplitude between the normal stress and the equivalent stress including torsional shear stress. The additional consideration of the torsional shear stress decreased the predicted fatigue life by 4.5%. The damage accumulation rate changes with the loading cycle, and it accelerates fast for the last 25% of the cycle, when the blade fracture may occur at any time. Thus, the aerodynamic excitation increased the safety factor of blade fatigue life prediction. Full article
(This article belongs to the Special Issue Multi-Axial Fatigue and Fracture Behavior in Metals)
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