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23 pages, 7582 KiB

Open AccessArticle

Tensile Behaviors and Mechanical Property Analyses of T-Welded Joint for Thin-Walled Parts in Consideration of Different TIG Welding Currents Using Multiple Damage Models and Fracture Criterions: Numerical Simulation and Experiment Validation

by Minghui Pan, Yuchao Li, Siyuan Sun, Wenhe Liao, Yan Xing and Wencheng Tang

Materials 2023, 16(13), 4864; https://doi.org/10.3390/ma16134864 - 6 Jul 2023

Cited by 1 | Viewed by 1630

Abstract

In order to deeply investigate the tensile properties and fracture behaviors that are obtained by tensile tests of welded joints, constitutive and damage models are imperative for analyzing the tensile behaviors. In this work, the tensile tests are conducted on the T-welded joint [...] Read more.

In order to deeply investigate the tensile properties and fracture behaviors that are obtained by tensile tests of welded joints, constitutive and damage models are imperative for analyzing the tensile behaviors. In this work, the tensile tests are conducted on the T-welded joint specimens of aluminum alloy 6061-T6, which were cut from the T-welded joints of thin-walled parts under different welding currents of Tungsten Inert Gas Welding (TIGW). A modified Johnson-Cook (J-C) model based on the original J-C equation, Swift model, Voce model, and Hockett-Sherby (H-S) model, their linear combination model, and fracture failure model are constructed and applied to simulate tensile behaviors, combined with tensile test data. What is more, the finite element (FE) simulation of tension tests is executed with the VUMAT and VUSDFLD subroutines. Compared to those results simulated with different fracture criteria and tensile experiments, the tensile strength and yield strength of T-welded joint thin-walled parts under different welding currents were achieved, and their best mean errors were only about 1%. Furthermore, the accuracy of different fracture criteria is also evaluated by the correlation coefficient and mean squared error. The results show that the combination model can accurately predict the tensile properties and fracture behaviors of T-welded joints better than the single model, especially the results simulated with the Swift-H-S model and H-S-Voce model, which are in good agreement with tensile test results, which will provide an analysis foundation for enhancing the welding assembly quality and preventing fracture failure for complex thin-walled antenna structures. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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17 pages, 4044 KiB

Open AccessArticle

LCF and HCF of Short Carbon Fibers Reinforced AE42 Mg Alloy

by Naser A. Alsaleh, Sabbah Ataya, Fahamsyah H. Latief, Mohamed M. Z. Ahmed, Ahmed Ataya and Akrum Abdul-Latif

Materials 2023, 16(10), 3686; https://doi.org/10.3390/ma16103686 - 12 May 2023

Cited by 2 | Viewed by 1788

Abstract

Lightweight magnesium alloys and magnesium matrix composites have recently become more widespread for high-efficiency applications, including automobile, aerospace, defense, and electronic industries. Cast magnesium and magnesium matrix composites are applied in many highly moving and rotating parts, these parts can suffer from fatigue [...] Read more.

Lightweight magnesium alloys and magnesium matrix composites have recently become more widespread for high-efficiency applications, including automobile, aerospace, defense, and electronic industries. Cast magnesium and magnesium matrix composites are applied in many highly moving and rotating parts, these parts can suffer from fatigue loading and are consequently subjected to fatigue failure. Reversed tensile-compression low-cycle fatigue (LCF) and high-cycle fatigue (HCF) of short fibers reinforced and unreinforced AE42 have been studied at temperatures of 20 °C, 150 °C, and 250 °C. To select suitable fatigue testing conditions, tensile tests have been carried out on AE42 and the composite material AE42-C at temperatures of up to 300 °C. The Wohler curves σ_a (N_F) have shown that the fatigue strength of the reinforced AE42-C in the HCF range was double that of unreinforced AE42. In the LCF range at certain strain amplitudes, the fatigue life of the composite materials is much less than that of the matrix alloys, this is due to the low ductility of this composite material. Furthermore, a slight temperature influence up to 150 °C has been established on the fatigue behavior of the AE42-C. The fatigue life curves Δε_total (N_F) were described using the Basquin and Manson–Coffin approaches. Fracture surface investigations showed a mixed mode of serration fatigue pattern on the matrix and carbon fibers fracturing and debonding from the matrix alloy. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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13 pages, 2137 KiB

Open AccessArticle

Stress Intensity Factor (SIF) Solutions and Fatigue Crack Paths in Eccentric Circumferentially Cracked Round Bar (CCRB) in Tension

by Jesús Toribio, Juan-Carlos Matos and Beatriz González

Materials 2023, 16(4), 1728; https://doi.org/10.3390/ma16041728 - 20 Feb 2023

Viewed by 1559

Abstract

In this paper, a numerical modeling was developed to study (on the basis of the Paris law) the fatigue propagation paths of eccentric external (outer) cracks in circumferentially cracked round bars (CCRB) subjected to a cyclic type of loading in the form of [...] Read more.

In this paper, a numerical modeling was developed to study (on the basis of the Paris law) the fatigue propagation paths of eccentric external (outer) cracks in circumferentially cracked round bars (CCRB) subjected to a cyclic type of loading in the form of either remote tensile loading or imposed axial displacement. Results show how the eccentricity (in relation to the wire axis) of the circular resistant ligament increases with the growth of outer circumferential cracks by subcritical fatigue mechanisms. This phenomenon is more pronounced when the solicitation consists of a remote tensile loading than when it is an axial displacement, when the initial eccentricity of the ligament increases (for a given initial diameter), and when the Paris exponent characteristic of the material rises. The paper also analyzes in depth the different situations regarding contact between crack faces during subcritical cyclic fatigue propagation, covering a wide range of cases including no contact, partial contact, and full contact depending on the ligament diameter (during the process of fatigue crack advance) and the relative eccentricity of the annular crack that loses its axial symmetry in relation to the round bar (cylinder) axis. In addition to the fatigue crack path study, closed-form stress intensity factor (SIF) solutions for the considered geometry (a cylinder with an outer annular crack) are provided in the form of third-degree polynomial expressions as a function of the ligament diameter and the crack eccentricity (both in dimensionless terms). Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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14 pages, 3438 KiB

Open AccessArticle

A Novel Ultrasonic Fatigue Test and Application in Bending Fatigue of TC4 Titanium Alloy

by Sen Tang, Xinyu Wang, Beihai Huang, Dongtong Yang, Lang Li, Chao He, Bo Xu, Yongjie Liu, Chong Wang and Qingyuan Wang

Materials 2023, 16(1), 5; https://doi.org/10.3390/ma16010005 - 20 Dec 2022

Cited by 2 | Viewed by 2149

Abstract

The very high cycle fatigue (VHCF) problems of thin-plate structures are usually caused by high-frequency vibrations. This paper proposes an accelerated fatigue test method based on ultrasonic loading technology in order to develop a feasible bending testing method and explore the bending fatigue [...] Read more.

The very high cycle fatigue (VHCF) problems of thin-plate structures are usually caused by high-frequency vibrations. This paper proposes an accelerated fatigue test method based on ultrasonic loading technology in order to develop a feasible bending testing method and explore the bending fatigue characteristics of thin-plate structures in the VHCF regime. A new bending fatigue specimen with an intrinsic frequency of 20 kHz was designed based on cantilever bending through finite element simulation. It was verified by the axial load test with R = −1. The results showed that the method could effectively transfer the dangerous cross-section at the first-order cantilever bending restraint to the internal part of the specimen, thereby making the fracture location independent of the complex stresses. The linear relationship between the vibration amplitude and the maximum stress was also verified using strain measurements. Furthermore, the S-N curves and fracture morphology for different loading types were consistent with conventional studies to a certain extent, which indicated that the design of the bending test model was reasonable. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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12 pages, 1370 KiB

Open AccessArticle

Numerical Investigation of the Influence of Aerodynamic Loads on the Resonant Frequency of a Compressor Blade Made of EI-961 Alloy

by Arkadiusz Bednarz, Krzysztof Puchała, Michał Sałaciński and Volodymyr Hutsaylyuk

Materials 2022, 15(23), 8391; https://doi.org/10.3390/ma15238391 - 25 Nov 2022

Cited by 2 | Viewed by 1596

Abstract

The aim of this work was to numerically determine the influence of aerodynamic loads on the value of the resonant frequency of the compressor blade. The object of the research was the 1st stage compressor blade of the PZL-10W engine. As part of [...] Read more.

The aim of this work was to numerically determine the influence of aerodynamic loads on the value of the resonant frequency of the compressor blade. The object of the research was the 1st stage compressor blade of the PZL-10W engine. As part of the research, analytical calculations of the resonance frequency were performed and compared with the literature ones (first, second, and third forms of forced vibrations). In the next step of the investigation, a computational model of the compressor stage (fluid domain and rotors) was built and FSI analysis was performed. This analysis was based on CFD modeling of the state of aerodynamic loads on the blade surfaces, and then these values were imported as external loads for the structural analysis, which was the basis for the modal analysis, in which the resonant frequency of the first three vibration modes was determined. As part of the analyzes, both the influence of aerodynamic loads and the rotational speed of the compressor rotor were verified. Thus, it was possible to evaluate the influence of both the rotational speed (and the arising centrifugal force) and the influence of the emerging aerodynamic load. The results obtained will allow for the assessment of the impact of the aforementioned operating conditions of the aircraft engine on the resonance frequency, which in turn may translate into the durability of critical components of the aircraft engine. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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20 pages, 23324 KiB

Open AccessArticle

Study on the Fatigue Crack Initiation and Growth Behavior in Bismuth- and Lead-Based Free-Cutting Brasses

by Kenichi Masuda, Sotomi Ishihara, Noriyasu Oguma, Minoru Ishiguro, Yoshinori Sakamoto and Mami Iwasaki

Materials 2022, 15(21), 7488; https://doi.org/10.3390/ma15217488 - 25 Oct 2022

Cited by 2 | Viewed by 1549

Abstract

Several studies have been conducted on the fatigue behavior of copper and 7-3, and 6-4 brasses. However, there have been fewer studies on the fatigue behavior and fatigue crack growth (FCG) properties of free-cutting brass, primarily because emphasis has been placed on the [...] Read more.

Several studies have been conducted on the fatigue behavior of copper and 7-3, and 6-4 brasses. However, there have been fewer studies on the fatigue behavior and fatigue crack growth (FCG) properties of free-cutting brass, primarily because emphasis has been placed on the development of lead-free free-cutting brass. In this study, fatigue experiments were performed in the atmosphere at room temperature using three types of free-cutting, two types of bismuth (Bi)-based (with different grain sizes), and lead (Pb)-based brasses. It was found that lead-free Bi-based free-cutting brass had approximately the same fatigue performance as that of Pb-based free-cutting brass. It was also clarified that the addition of Bi or Pb initiated fatigue cracks, and that the crack growth period occupied most of the fatigue life. Differences in the FCG behavior of the three free-cutting brasses were observed in the low ΔK range. The modified linear fracture mechanics parameter M was used to quantitatively analyze the fatigue life and FCG behavior (short surface cracks). A comparison between the calculated and experimental results showed that M was useful. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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15 pages, 7307 KiB

Open AccessArticle

Characterization of Fatigue Crack Growth Based on Acoustic Emission Multi-Parameter Analysis

by Mengyu Chai, Chuanjing Lai, Wei Xu, Quan Duan, Zaoxiao Zhang and Yan Song

Materials 2022, 15(19), 6665; https://doi.org/10.3390/ma15196665 - 26 Sep 2022

Cited by 16 | Viewed by 2028

Abstract

In engineering structures that are subject to cyclic loading, monitoring and assessing fatigue crack growth (FCG) plays a crucial role in ensuring reliability. In this study, the acoustic emission (AE) technique was used to monitor the FCG behavior of 2.25Cr1Mo0.25V steel in real-time. [...] Read more.

In engineering structures that are subject to cyclic loading, monitoring and assessing fatigue crack growth (FCG) plays a crucial role in ensuring reliability. In this study, the acoustic emission (AE) technique was used to monitor the FCG behavior of 2.25Cr1Mo0.25V steel in real-time. Specifically, an AE multi-parameter analysis was conducted to qualitatively assess the crack growth condition and quantitatively correlate the crack growth rate with AE. Various AE parameters were extracted from AE signals, and the performances of different AE parameters were analyzed and discussed. The results demonstrated that four stages of FCG, which correspond to macrocrack initiation, stable crack growth with low crack growth rate, stable crack growth with high crack growth rate, and unstable crack growth, are distinctly identified by several AE time domain parameters. The sudden and continuous occurrence of many AE signals with high count (>100) and high energy (>40 mV·ms) can provide early and effective warning signs for accelerated crack growth before final failure occurs. Moreover, linear correlations between crack growth rate and different AE parameters are established for quantifying crack growth. Based on the AE multi-parameter analysis, it was found that the count, energy, and kurtosis are superior AE parameters for both qualitatively and quantitatively characterizing the FCG in 2.25Cr1Mo0.25V steel. Results from this research provide an AE strategy based on multi-parameter analysis for effective monitoring and assessment of FCG in engineering materials. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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8 pages, 6428 KiB

Open AccessArticle

In Vitro Analysis of the Fatigue Resistance of Four Single File Canal Preparation Instruments

by Mohammad I. Al-Obaida, Abdulmohsen A. Alzuwayer, Saqer S. Alanazi and Abdulrahman A. Balhaddad

Materials 2022, 15(2), 688; https://doi.org/10.3390/ma15020688 - 17 Jan 2022

Cited by 9 | Viewed by 2208

Abstract

Instrument separation during root canal therapy is inevitable in endodontics with several unfavorable clinical consequences. Therefore, examining the cyclic flexural fatigue resistance of commonly used rotary endodontic files is crucial. This study aimed to determine the cyclic flexural fatigue resistance of four nickel–titanium [...] Read more.

Instrument separation during root canal therapy is inevitable in endodontics with several unfavorable clinical consequences. Therefore, examining the cyclic flexural fatigue resistance of commonly used rotary endodontic files is crucial. This study aimed to determine the cyclic flexural fatigue resistance of four nickel–titanium (NiTi) rotary files used as a single canal preparation technique: WaveOne, Reciproc, Protaper F2, and Unicone medium instruments. According to the manufacturer’s instructions, each file was rotated freely within a 1.3 mm deep and 1.3 mm wide V-shaped groove in a stainless-steel block with a 40° and 5 mm radius of curvature. Cyclic fatigue resistance was compared between the NiTi files by verifying the time needed to crack. The data were analyzed using one-way analysis of variance (ANOVA) followed by Scheffé post hoc with a significant level set at p < 0.05. Our results demonstrated that the WaveOne instrument had the highest cyclic flexural fatigue resistance among the tested groups (p ≤ 0.05), while Unicone had the lowest cyclic flexural fatigue resistance. This study concluded that WaveOne size 25/0.08 could illustrate a superior cyclic flexural fatigue resistance when instrumenting root canals with the lowest possibility to cause instrument separation. Full article

(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)

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