Article
Chemistry, Physical
Jesus Toribio, Beatriz Gonzalez, Juan-Carlos Matos
Summary: This article explores the influence of crack path branching on plasticity-induced fatigue crack growth, finding a retardation effect in growth rate in different cases. It shows that the growth rate depends on factors such as branch length, initial projected length, branch angle, fatigue intensity, and distance between bifurcated crack tips.
Article
Engineering, Mechanical
Florian Paysan, Eric Breitbarth
Summary: This study investigates plasticity-induced crack closure in AA2024 aluminium sheet material under constant amplitude loading from a three-dimensional perspective. The results show that crack closure is present up to a load ratio of R = 0.3, and the contact pressure distributions are strongly influenced by the stress intensity factors and sheet thicknesses.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Mechanics
Meiling Xu, Yujin Liu, Huang Yuan
Summary: This paper computationally confirms that the crack-tip field of elastoplastic fatigue crack growth without crack closure possesses the known HRR solution form, but the plasticity-induced crack closure dramatically changes the crack characterization. The effective AJ-integral can be used to characterize fatigue crack growth with a smaller dominance zone than the conventional HRR zone.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
Simon Lubich, Carl Fischer, Simon Schilli, Thomas Seifert
Summary: In this paper, the effect of the polycrystalline microstructure on crack-tip opening displacement and crack closure is investigated. It is found that the crack opening stress and cyclic crack-tip opening displacement are significantly influenced by the local grain structure, and the differences in the cyclic crack opening displacement are attributed to the asymmetric plastic strain fields in the plastic wake behind the crack-tip of the microstructure-based model.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Prabhu Murugesan, Youngbin Lim, Sunghwan Jung, Hyungyil Lee
Summary: The study proposes to generate compressive residual stress at the crack tip in bulk metal by introducing acoustic cavitation, which effectively retards crack growth. The experiments conducted using pre-cracked specimens showed that acoustic cavitation can produce significant compressive residual stress at the crack tip, offering potential applications in extending material fatigue life.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Mechanics
Anbang Qu, Fanchun Li
Summary: Taking compressor impeller with pressure ratio less than 3 as research object, a prediction method of residual life of compressor impeller was proposed. Finite element method (FEM) technology and sub-model technology were used to analyze the mechanical quantities and determine the hot spot stress location of compressor impeller. Crack growth was investigated using linear elastic fracture mechanics (LEFM) and Forman-Newman-de Koning (FNK) model. The results showed that the stress intensity factor, critical length, and residual life of impeller varied with rotate speed.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Mechanical
G. L. Gomez Gonzales, F. V. Antunes, E. R. Sergio, J. M. Vasco-Olmo, F. A. Diaz, D. M. Neto
Summary: In this study, the accuracy of a finite element model was validated by comparing its predictions with experimental results. The qualitative comparison showed a strong similarity between the displacement field predicted by the model and the experimental results. Although there were differences in the comparison of CTOD curves obtained behind the crack tip, the analysis revealed that the interior regions have a significant influence on the displacement field.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Chemistry, Physical
Takayuki Shiraiwa, Fabien Briffod, Manabu Enoki
Summary: A method for predicting fatigue crack initiation of the 7075 aluminum alloy by crystal plasticity finite element analysis considering microstructures was proposed in this study. The calculated crack initiation life and morphology were in good agreement with the experimental results, indicating the effectiveness of the proposed method in predicting fatigue crack initiation in aluminum alloys.
Article
Mechanics
St. Gesell, R. Ganesh, M. Kuna, B. Fedelich, B. Kiefer
Summary: Crack propagation under low cycle fatigue and thermomechanical fatigue is characterized by high plastic and creep strains that require different approaches for quantifying crack growth. The cyclic crack tip opening displacement (ACTOD) is investigated as a promising loading parameter. A viscoplastic temperature dependent material model is used along with special crack tip elements for accurate calculation. An efficient FE-technique is developed for simulating fatigue crack growth by successive remeshing and recommendations are made for important numerical control parameters.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Chemistry, Physical
Yann Charles, Jonathan Mougenot, Monique Gasperini
Summary: The paper revisits the transient trapping model for hydrogen transport and finds that the improved formulation may lead to non-physical results in insulated systems. The McNabb and Foster trapping kinetic equation is more relevant and has a significant effect on the hydrogen distribution.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Engineering, Mechanical
Sang Min Lee, Sang-Youn Park, Un Bong Baek, Byoung-Ho Choi
Summary: The effect of high-pressure hydrogen on an SA-372 Grade J steel pressure vessel was analyzed through fatigue crack growth testing, fracture toughness testing, and finite element analysis. The test results, including the degradation of fracture toughness and the presence of hydrogen inflection in the fatigue crack growth rate, were used in the finite element analysis to analyze the fatigue crack growth behavior under different conditions. The residual fatigue life was evaluated considering the morphological evolution of the crack, the initial aspect ratio, and the initial crack-to-depth ratio.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
Alireza Golahmar, Philip K. Kristensen, Christian F. Niordson, Emilio Martinez-Paneda
Summary: A new theoretical and numerical approach based on phase field has been proposed for predicting hydrogen-assisted fatigue. The role of hydrogen in fatigue crack growth is investigated, and virtual S-N curves for both notched and smooth samples are obtained, showing good agreement with experiments.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
Yuhei Ogawa, Keiichiro Iwata, Saburo Okazaki, Masami Nakamura, Kazuki Matsubara, Osamu Takakuwa, Hisao Matsunaga
Summary: Hydrogen affects crack-tip plastic-zone development by sharpening the crack tip shape, suppressing the extension of severely-deformed zone, and enhancing crack-tip branching, leading to a slower crack growth rate. However, it barely alters the overall plastic-zone size between in-air and hydrogen-gas conditions.
Article
Nanoscience & Nanotechnology
Abdul Khadar Syed, Xiang Zhang, Alec E. Davis, Jacob R. Kennedy, Filomeno Martina, Jialuo Ding, Stewart Williams, Philip B. Prangnell
Summary: The influence of three different deposition strategies on the fatigue crack growth behavior of WAAM Ti-6Al-4V was studied. The oscillation build exhibited the lowest crack growth rates and behaved more similarly to an annealed microstructure compared to the other two deposition strategies.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Mathematics, Applied
Chen Xing, Chuwei Zhou, Yulin Sun
Summary: This paper presents a novel method to construct a plate element enveloping crack tip in the extended finite element method (XFEM) frame for crack growth simulation. The proposed method can model cracks independent of the background mesh by sub-partitioning the crack tip element and enriching it with the Heaviside function. The use of singular elements instead of analytical asymptotic functions allows for reflecting the crack tip singularity for more fracture scenarios. The performance of the proposed method is investigated through stress intensity factors (SIFs) prediction, convergence study, and fatigue crack growth analysis in several examples.
FINITE ELEMENTS IN ANALYSIS AND DESIGN
(2023)
Article
Chemistry, Physical
Jesus Toribio, Miguel Lorenzo, Leticia Aguado
Summary: This study analyzed the stress and strain fields under different loading conditions and notch geometries to investigate the influence of these factors on hydrogen diffusion and susceptibility to hydrogen embrittlement. The results showed that hydrogen accumulation is localized near the surface in shallow notches, while it is more uniformly distributed in deep notches. The residual stress and strain generated by preload caused maximum hydrogen concentration at deeper points. Four different scenarios were established to estimate the hydrogen embrittlement susceptibility of pearlitic steels.
Article
Chemistry, Physical
Jesus Toribio, Beatriz Gonzalez, Juan-Carlos Matos, Ivan Gonzalez
Summary: This paper numerically investigates the effect of an eccentric circular inner crack on the stress intensity factor (SIF) in notched bars subjected to tensile loading. The results show a higher SIF value in notched bars, with an increase in the axial semi-axis of the notch and the size of the inner crack resulting in a greater effect.
Article
Engineering, Multidisciplinary
Rocio Rodriguez, Manuel Curado, Elena Sardina, Jesus Toribio
Summary: The research proposes a simple and feasible mechanical male plug protection mechanism to solve the problem of electrical shock caused by user contact with active parts during connection and disconnection. The implementation of this mechanism is of great importance in preventing serious accidents in the field of domestic and industrial electrical use.
Article
Chemistry, Physical
Jesus Toribio, Francisco-Javier Ayaso, Rocio Rodriguez
Summary: This paper investigates the intercolonial microdamage (ICMD) induced by drawing in pearlitic microstructures. Through direct observation of the microstructure of progressively cold-drawn pearlitic steel wires, three types of ICMD were identified: intercolonial tearing, multi-colonial tearing, and micro-decolonization, all affecting two or more pearlite colonies. The evolution of ICMD is highly relevant to the subsequent fracture process of cold-drawn pearlitic steel wires, as the drawing-induced micro-defects act as weakest links or fracture promoters/initiators, affecting the microstructural integrity of the wires.
Article
Chemistry, Physical
Jesus Toribio, Juan-Carlos Matos, Beatriz Gonzalez
Summary: A numerical modeling was developed to study the fatigue propagation paths of eccentric external cracks in circumferentially cracked round bars subjected to cyclic loading. The study found that the eccentricity of the circular resistant ligament increases with the growth of outer circumferential cracks, especially under remote tensile loading. The paper also analyzed the contact between crack faces during subcritical cyclic fatigue propagation and provided closed-form stress intensity factor solutions for the considered geometry.
Article
Materials Science, Multidisciplinary
Jesus Toribio, Miguel Lorenzo
Summary: The effects of the skin pass technique on the residual stress and plastic strain fields in cold drawn pearlitic steel wires are analyzed in this study. The goal is to find optimal conditions for manufacturing more reliable structural components by reducing the main cause of failure, hydrogen embrittlement. Numerical simulations using finite elements and considering different drawing dies and reduction ratios were performed to estimate the hydrogen distributions. Results showed that the reduction ratio is a key parameter in reducing the drawing-induced residual stress, and the use of modified drawing dies with a skin pass zone can lead to lower hydrogen accumulation in the prospective damage zone.
Article
Materials Science, Multidisciplinary
Jesus Toribio, Miguel Lorenzo
Summary: This study compares the strain and residual stress states of two different commercial cold-drawn wires during the manufacturing process and their susceptibility to hydrogen embrittlement (HE) in a hydrogen environment. Numerical simulations using the finite element (FE) method are conducted to evaluate the hydrogen accumulation in the wires under different strain and residual stress states. The results show that the hardening history modifies the residual stress and strain states of the wires, affecting their behavior in hydrogen environments.
Article
Materials Science, Multidisciplinary
Jesus Toribio
Summary: This paper investigates the hydrogen-assisted microdamage (HAMD) in fully-pearlitic steel. Detailed analysis is conducted on the HAMD region in axisymmetric round-notched samples of high-strength eutectoid pearlitic steel under hydrogen embrittlement environmental conditions. The microstructural changes from initiation to fracture situations due to hydrogen degradation are examined, and the role of triaxial stress state on hydrogen diffusion and micro-cracking is studied.
Article
Materials Science, Multidisciplinary
Jesus Toribio, Juan-Carlos Matos, Beatriz Gonzalez, Ivan Gonzalez
Summary: This paper obtained stress intensity factor (SIF) solutions of eccentric annular external cracks in elliptical notched round bars under tension loading through 3D finite element analysis, and their relation to the energy release rate obtained with the J-integral contour. The variables analyzed were the ligament diameter, its eccentricity, and the elliptical notch aspect ratio. The maximum SIF increases with the ligament eccentricity, the presence of the notch (compared to when the bar is smooth), and the elliptical notch axial semi-axis (for the same notch depth); it decreases with the ligament diameter.
Article
Materials Science, Multidisciplinary
Jesus Toribio, Francisco-Javier Ayaso, Rocio Rodriguez
Summary: The final aim of this paper is to study the microstructural changes in the necking region of progressively cold-drawn pearlitic steel wires by analyzing pearlite interlamellar spacing and Vickers micro-hardness. A set of cold-drawn pearlitic steel wires were subjected to tension tests, with the tests interrupted at the necking instant. Changes in microstructure were evaluated by measuring interlamellar spacing and micro-hardness. The research aims to determine the local areas in the necking region where microstructural changes are most evident and affect mechanical response during tension tests.
Article
Engineering, Multidisciplinary
Rocio Rodriguez, Manuel Curado, Rosario Pastor, Jesus Toribio
Summary: The cleaning of the ear canal is essential and should be performed by an otolaryngologist. Accumulation of earwax can lead to hearing loss and discomfort. This study aims to develop a safe and comfortable ear cleaning tool for patients with self-cleaning disorders.
Proceedings Paper
Construction & Building Technology
Jesus Toribio, Beatriz Gonzalez, Juan-Carlos Matos
Summary: The stress intensity factor (SIF) in a circumferentially-cracked round bar (CCRB) under tensile load is computed using the finite element method (FEM), considering the eccentricity of the resistant ligament. The results show that the SIF is higher at the deepest point of the crack and that an increase in eccentricity raises the difference between the SIF values at the deepest and surface points of the crack.
4TH INTERNATIONAL CONFERENCE ON STRUCTURAL INTEGRITY (ICSI 2021)
(2022)
Proceedings Paper
Construction & Building Technology
Jesus Toribio, Beatriz Gonzalez, Juan-Carlos Matos
Summary: In this paper, the stress intensity factor (SIF) in a bar subjected to tensile loading is calculated using the finite element method (FEM) and the J-integral. The results show that the SIF is higher at the point of the crack front closest to the bar surface, and an increase in crack eccentricity or diameter raises the difference between the SIF values at the opposite crack points.
4TH INTERNATIONAL CONFERENCE ON STRUCTURAL INTEGRITY (ICSI 2021)
(2022)
Proceedings Paper
Construction & Building Technology
Jesus Toribio, Beatriz Gonzalez, Juan-Carlos Matos
Summary: This paper analyzes the different stress intensity factor (SIF) solutions obtained from previous research on transversely cracked cylinders (round bars) subjected to tension loading. The solutions assume semi-elliptical surface cracks or flaws, and compare SIF values at the crack front center and the external surface of the cylinder. The study covers a wide range of crack aspect ratios and relative crack depths to provide applicable solutions to various real situations in fracture mechanics or damage tolerance analyses, such as static or cyclic (fatigue) loading, environmentally-assisted cracking, or corrosion-fatigue.
4TH INTERNATIONAL CONFERENCE ON STRUCTURAL INTEGRITY (ICSI 2021)
(2022)
