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
Mechanics
M. Ciavarella
Summary: This article discusses the applicability of energy balance for large cracks and introduces the influence of liquid materials and viscoelasticity on flaw sensitivity. A comparison is made between different theories using a simple Dugdale model, revealing significant differences.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
Sarah A. Paluskiewicz, Santosh B. Narasimhachary, Sachin R. Shinde, Chris Kain, Zachary B. Towner, Christopher L. Muhlstein
Summary: This study investigates the fatigue crack growth mechanisms in nickel-based superalloys under high, negative stress ratios, challenging the classical crack tip shielding and closure concepts. The fatigue crack growth rates and closure levels were evaluated for nickel-based superalloy 718 specimens with single edge notches at 100 degrees C under different stress ratios. Multiple methods were used to calculate the effective driving force for crack growth rates, and the relationships between the effective driving forces, experimentally-measured crack closure levels, and fractographic evidence of damage mechanisms are discussed.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
Lifu Cheng, Xinyuan Chen, Guoqian Wei, Fan Ye
Summary: This study focuses on the plastic zone and initiation behavior of microscopic short cracks in different zones of the weld. Results show that crack initiation mainly occurs in the base metal zone, and the crack expansion rate varies with the grain gradient.
Article
Mechanics
Valary Tubei, Hiroyuki Toda, Meysam Hassanipour, Kyosuke Hirayama, Osamu Takakuwa, Akihisa Takeuchi, Masayuki Uesugi
Summary: In-situ synchrotron X-ray microtomography was used to investigate the 3D closure behavior of short fatigue cracks in Ti-6Al-4V alloy. The study observed the evolution of closure behavior influenced by crack path morphologies and microstructural features.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Acoustics
Hyun Woo Park, Jin Ho Hwang
Summary: This paper presents a generic frequency equation and its approximate solution for a one-dimensional waveguide with incipient open cracks, which is physically intuitive and easy to understand. The validity of the proposed frequency equation is demonstrated through comparisons with numerical results, finite element analysis, and experimental data for a Timoshenko beam with multiple incipient cracks.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Mechanics
Suresh S. Kumar, Arjun Shyam Sundar, R. Deepak
Summary: The stress intensity factor (SIF) of opposite surface cracks in an un-notched round bar under tension and combined load conditions was determined using a numerical method. The influence of loading modes on SIF was investigated, considering different crack depth ratios and crack aspect ratios. It was found that the SIF distribution changed as the crack depth ratio increased under pure tensile loading, and nonuniform and asymmetric SIF spread was observed when torque was applied. The effect of mode-II and mode-III fractures was more pronounced under combined loading.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Instruments & Instrumentation
Beate Oswald-Tranta
Summary: Inductive thermography is effectively used to detect surface cracks in metals by inducing eddy currents and recording surface temperature distributions. This study investigates the influence of different parameters on the surface patterns around short cracks, showing that crack geometry significantly affects the intensity of temperature 'hot spots'. Additionally, experimental parameters such as excitation frequency and heating pulse duration are explored to optimize the experimental setup.
QUANTITATIVE INFRARED THERMOGRAPHY JOURNAL
(2022)
Article
Materials Science, Ceramics
Hui Dong, Long Xu, Pan-Hu Zhou, Guan-Jun Yang, Li-Shuang Wang, Jian-Tao Yao
Summary: The phase transition of atmospheric plasma-sprayed yttria-stabilized zirconia (APS YSZ) coating over delamination cracks in thermal barrier coatings (TBCs) was investigated. The coupling effect of delamination cracks and vertical cracks on the phase transition in TBCs was illustrated. The temperature in the YSZ coating was significantly elevated by the combination of vertical cracks and delamination cracks.
CERAMICS INTERNATIONAL
(2023)
Article
Engineering, Geological
Chengzhi Qi, Fa Zhao, Arcady Dyskin, Chen Xia, Elena Pasternak
Summary: This study proposes a three-level mechanical model of cracks to investigate their propagation patterns and failure modes. The research shows that different initial crack concentrations result in different patterns of crack propagation and failure.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Mechanics
K. Tanaka, Y. Akiniwa
Summary: A modified strip-yield model is used to simulate plasticity-induced crack closure in the wake of advancing cracks, with different lengths of precracks, under fully reversed loading. Two types of precracks, open and closed, are examined to understand their effects on fatigue thresholds. The results show that the crack opening stress and effective stress intensity range Delta Keff have significant influence on fatigue thresholds, and new master curve equations are proposed for the cyclic R-curve.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Mechanics
Mikel Escalero, Miguel Muniz-Calvente, Haritz Zabala, Iker Urresti
Summary: Extensive literature suggests that fatigue cracks tend to reach a stable stage with a quasi-constant crack shape under the influence of an iso crack driving force (CDF) distribution. This study investigates fatigue crack growth using a finite element simulation approach and a theoretical analysis. The results contradict previous findings and demonstrate that naturally growing fatigue cracks converge towards a quasi-constant crack-shape regime, influenced by a non-iso CDF distribution dependent on material properties and the stable crack shape.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Civil
Jian-Hua Jiang, Yong-Quan Fu, Fei-Fei Hu, Wei-Xin Weng
Summary: By conducting experiments and numerical simulations, it was found that various factors such as crack formation and water-cement ratio can impact the temperature response of concrete. The rate and trend of temperature response are both influenced by these factors under different conditions.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2021)
Article
Engineering, Mechanical
Diego Erena, Jesus Vazquez, Carlos Navarro, Jaime Dominguez
Summary: In this article, a new fretting fatigue life prediction model is proposed, which automatically determines the crack direction based on the crack initiation length, and obtains excellent correlation between experimental and predicted results.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Chemistry, Physical
Hongbin Shang, Zhiyuan Lin, Hongli Gao, Xiaofeng Shan, Jingsong Zhan
Summary: This paper proposes a novel method for measuring dual microscopic fatigue-crack and tip-deformation-fields using a hybrid image-processing technique. The method is applied to research the physical short fatigue crack (SFC) closure effect and the evolution law of the tip deformation fields of Quenching-Partitioning (Q&P) steel during the crack-closure process. The method effectively solves the measurement problems associated with small crack tip regions, large deformation gradients, and strong material anisotropy. The results show that the stress ratio affects the crack-closure behavior and crack growth rate of Q&P steel in the physical SFC crack-growing stage. The research provides experimental and theoretical support for further studies on the SFC growth mechanism and fatigue life prediction of Q&P steel.
Review
Chemistry, Physical
Sudip Kundu, Rhys Jones, Daren Peng, Neil Matthews, Alankar Alankar, Singh R. K. Raman, Pu Huang
Article
Engineering, Mechanical
Rhys Jones, Jeff Lang, Vahram Papyan, Daren Peng, Jim Lua, Andrew Ang
Summary: This paper reveals that commercially pure (CP) Titanium has superior corrosion resistance, fracture toughness, and fatigue crack growth resistance compared to commonly used aluminum alloy AA7050-T7451. CP Titanium may be an attractive option for replacement parts in aircraft and unmanned aerial vehicles (UAV's).
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Chemistry, Physical
Rhys Jones, Calvin Rans, Athanasios P. Iliopoulos, John G. Michopoulos, Nam Phan, Daren Peng
Summary: The study examines the variability in crack growth in AM Ti-6Al-4V specimens and highlights the ability of the Hartman-Schijve crack growth equation to capture this variability and anisotropic behavior. Despite the large variability in crack growth, the intrinsic crack growth equation remains unchanged, with changes in both the fatigue threshold and cyclic fracture toughness accounting for the variability and anisotropy observed in the test program.
Article
Multidisciplinary Sciences
Anthony J. Kinloch, Rhys Jones, John G. Michopoulos
Summary: This paper presents detailed analyses of experimental data on the cyclic-fatigue behavior of epoxy nanocomposite polymers. It establishes key materials parameters and their relationship to the observed fracture and fatigue behavior of these materials, providing insights for material development, selection, design, and service-life prediction in engineering applications.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Chemistry, Physical
Daren Peng, Caixian Tang, Neil Matthews, Rhys Jones, Sudip Kundu, R. K. Singh Raman, Alankar Alankar
Summary: This paper summarises a study on the durability of cold spray repairs to simulated corrosion damage in AA7075-T7351 aluminium alloy specimens, demonstrating how to perform the mandatory durability analysis of repaired corroded structures in accordance with specified requirements.
Review
Chemistry, Physical
R. K. Singh Raman, Rhys Jones
Summary: Stress corrosion cracking (SCC) poses a challenge for load-bearing equipment in corrosive environments across industries like aerospace, chemical and mineral processing, civil structures, bioimplants, and energy generation. Reliable K-ISCC data is crucial for safe operation and maintenance of such equipment, with traditional techniques being costly. This article highlights the use of the circumferential notch tensile (CNT) technique as a newer and more cost-effective approach to determine K-ISCC, overcoming critical limitations of traditional techniques like double-cantilever beam (DCB) and compact tension (CT).
Article
Engineering, Mechanical
Muhammad Shamir, Victor Igwemezie, Saeid Lotfian, Rhys Jones, Huzaifa Asif, Supriyo Ganguly, Ali Mehmanparast
Summary: A study was conducted to evaluate the mechanical and fatigue crack propagation properties of wire + arc additively manufactured ER70S-6 components. The hardness values were slightly higher at the bottom and top of the wall. There was a marginal difference in mechanical properties between orientations. The crack growth rates of both deposition strategies were found to be very similar, and the NASGRO crack growth equation can capture the variability in crack growth histories reasonably well.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Daren Peng, Rhys Jones, Andrew S. M. Ang, Victor Champagne, Aaron Birt, Alex Michelson
Summary: This paper analyzes the effect of surface roughness and machining on the durability of AM parts using LEFM and a valid small crack growth equation. The results show that the component's life is strongly influenced by surface roughness and the local radius of the curvature of the trough.
Article
Engineering, Mechanical
Daren Peng, Rhys Jones, Andrew S. M. Ang, Alex Michelson, Victor Champagne, Aaron Birt, Samuel Pinches, Sudip Kundu, Alankar Alankar, Raman R. K. Singh
Summary: This paper illustrates the durability analysis required to certify an additively manufactured part by using the examples of durability tests performed on two wire arc additively manufactured (WAAM) 18Ni 250 Maraging steel specimens.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Letter
Engineering, Mechanical
Daren Peng, Rhys Jones, Andrew S. M. Ang, Alex Michelson, Victor Champagne, Aaron Birt
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Chemistry, Physical
Daren Peng, Andrew S. M. Ang, Alex Michelson, Victor Champagne, Aaron Birt, Rhys Jones
Summary: The partial machining of WAAM 18Ni 250 Maraging steel surfaces may not significantly improve their durability, as shown in the study, and only through full machining to completely remove any remnants of print artefacts can the improvement in durability be realized.
Article
Crystallography
Daren Peng, Victor K. Champagne, Andrew S. M. Ang, Aaron Birt, Alex Michelson, Sam Pinches, Rhys Jones
Summary: The durability assessment of additively manufactured parts must consider both surface-breaking material discontinuities and porosity, and how these factors interact with as-built parts. The authors have previously shown how the Hartman-Schijve variant of the NASGRO crack growth equation can predict the durability of wire arc additively manufactured specimens with surface-breaking cracks due to surface roughness. This paper demonstrates that the same equation can also be used to predict the durability of specimens with failure caused by surface-breaking porosity.
Article
Materials Science, Multidisciplinary
Rhys Jones, Andrew Ang, Daren Peng, Victor K. K. Champagne, Alex Michelson, Aaron Birt
Summary: This paper investigates crack growth in both additively manufactured (AM) and conventionally manufactured Inconel 718, as well as Inconel 625. It is found that when the crack growth rate (da/dN) is plotted as a function of the stress intensity factor range (& UDelta;K), there is considerable scatter. However, when da/dN is expressed in terms of the Schwalbe crack driving force (& UDelta;& kappa;), all curves collapse onto a single curve. This observation challenges the materials science community to address the underlying fundamental science.
Article
Engineering, Aerospace
Rhys Jones, Daren Peng, Andrew Ang, Richard W. Aston, Nicole D. Schoenborn, Nam D. Phan
Summary: This paper presents the results of an experimental study on the damage tolerance of AA7075-T6 and LBPF Scalmalloy specimens built by Boeing. The study reveals that Boeing's AM-built Scalmalloy is more damage tolerant than conventionally built AA7075-T6. It suggests the potential for using AM-built Scalmalloy to extend the operational lives of military aircraft by 3D printing replacement parts.
Article
Engineering, Manufacturing
Rhys Jones, Ondrej Kovarik, Jan Cizek, Andrew Ang, Jeff Lang
Summary: Recent studies have shown that the da/dN versus ΔK curves associated with crack growth in different manufacturing methods can collapse onto a single master curve, indicating the independence of crack growth behavior from manufacturing processes.
ADDITIVE MANUFACTURING LETTERS
(2022)
Article
Engineering, Mechanical
Willy Ank de Morais, Railson Bolsoni Falcao, Mario Boccalini Jr, Fernando Jose Gomes Landgraf
Summary: This study compares the fatigue behavior of bcc Nb-48 wt%Ti (Ti-36at%Nb) alloy parts processed by Laser Powder Bed Fusion (L-PBF) using two different types of powders (spherical powder produced by Plasma Atomization and irregularly shaped powder produced by Hydride-Dehydride). The results show that the fatigue behavior is similar for both powders, but the specimens produced from the Hydride-Dehydride powder have higher dispersed results. Fracture primarily occurs in the porosities near the machined sample surface, and the fatigue cracks propagate in a zigzag mode parallel to the L-PBF building direction.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Guoxi Jing, Shuai Sun, Teng Ma, Shubo Li, Tian Ma, Junchao Wei, Jianchao Pang
Summary: This study proposes a parameter identification method for predicting the TMF life of CGI materials used in cylinder heads. The study evaluates the TMF behavior of RuT450 material and successfully predicts its TMF life using multi-objective optimization. The results highlight the influence of plastic strain amplitude, temperature, and strain rate on the damage mechanism and life prediction.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Xin Zhang, Xu Li, Weipeng Xu, Kuidong Gao, Kao Jiang, Xinyu Wang, Hongxin Wei
Summary: Conical picks are commonly used in tunnel excavation and often experience high temperatures during the cutting process. This study investigated the influence of temperature on the wear of conical picks and proposed a method for measuring rock abrasiveness that takes into account the thermal effect. The experimental results showed that cooling liquid reduced the maximum temperature and the mean mass loss of the conical pick. Additionally, the study examined the characteristics of oxygen and found evidence of peeling, cracking, and oxidation on the grinding rod used for rock abrasiveness measurement.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Vivek Srivastava, Deependra Singh, A. G. Rao, V. P. Deshmukh
Summary: Engine gear failures are a significant concern in various industries. Investigating each gear failure and determining the root cause is important for preventing future failures. This study used experimental and numerical analysis techniques to investigate the premature failure of a flywheel gear in a marine diesel engine. The findings revealed that the gear failed due to overload stresses caused by overload torque generated from sudden inertial thrust in the internal combustionengine.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Jun Zhang, Weidong Liu, Feilong Liu, Zhiqiang Yang, Jinfang Peng, Minhao Zhu
Summary: During a major overhaul of an aeroengine, a cracked stator vane of the low-pressure compressor was discovered, with the crack originating from a corrosion pit located on the arc transition between the leading edge and the upper edge plate. The fracture surface exhibited signs of fatigue cracks, indicating a pit-related fatigue crack. Metallographic examination revealed that most corrosion pits were distributed beneath the bulging or peeling paint layer on the leading edge and the concave side. Identification of the corrosion products showed the presence of sulfate and alumina, suggesting atmospheric corrosion as a likely cause for the cracked stator vane.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Juan Jose Jimenez de Cisneros Fonfria, Ester Olmeda, Susana Sanz, Maria Garrosa, Vicente Diaz
Summary: Energy absorbing devices in vehicles can partially transform impact energy and protect passengers. In this paper, the failure analysis of the underframe crumple zone in a train car was conducted through finite element simulations, showing that the component acted properly after the impact.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Fengqi Zhang, Gang Luo, Haiyang Zhang, Peihong Cong, Lulu Liu, Wei Chen
Summary: In this study, a predictive model for bird strike trajectory was developed based on the quasi-linear viscoelastic model. By combining simulation analysis under multiple conditions, the model reproduced the trajectory change law in low and medium speed bird impact experiments.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
S. M. de Gouveia, L. de Abreu Correa, D. B. Teles, M. Oliveira, T. G. R. Clarke
Summary: Emergency Shutdown Valves (EDSVs) are used in industrial applications to interrupt fluid flow during hazardous events. The damage to the valve seats can be detected by analyzing the pressure and torque data. This study compared three processing options and found that evaluating the complete signature with a Gradient Boosting Classifier algorithm is the most effective strategy.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Xinyan Jin, Kai Wang, Hongwei Qian
Summary: This study investigated the root cause of an abnormal premature groove-clogging failure on a sink roll in a hot-dip galvanizing line. It was found that the failure was caused by the buildup of a large amount of Fe2Al5Znx dross in the grooves, and the key factor was the control of Tstrip.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Zhiqiang Li, Jie Li, Cen Li, Xiaodong Xie, Zhiyong Yang
Summary: In this study, the microstructure evolution of the material in the hot spot area of the high-speed train brake disc was observed and the mechanism of mechanical property degradation was obtained through tensile tests. The research results provide guidance for crack damage identification of the brake disc and condition-based maintenance.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Lijia Luo, Yincheng Wang, Wei Chen, Zuming Zhao, Wenfei Chen, Shiyi Bao
Summary: Tube-to-tube impact wear is a significant factor in the failure of alloy 690 tubes in nuclear steam generators. This paper investigates the wear damage mechanism and detection method of alloy 690 tubes under tube-to-tube impact loads. The results reveal the wear damage mechanism through analysis of macro and micro morphologies as well as metallographic structures. A nonlinear ultrasonic wave mixing method is proposed for damage detection and a detection device is developed to implement this method. Experimental results indicate that the damage mode of tube-to-tube impact wear varies with impact load and cycle number, and the nonlinear modulation index is effective in assessing the damage degree of alloy 690 tubes.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Xing-Ju Yang, Feng Lin, Xu Du, Lu Qiu
Summary: This paper proposes a novel method of improving the progressive collapse resistance of RC frame structures by adding locally debonded kinked steel plates (KPs). Experimental tests and finite element analysis reveal that the addition of KPs significantly enhances the ultimate resistance and deformability of the beam-slab substructures. The mechanism of resistance improvement is explained, and an analytical model is developed for predicting the ultimate resistance of the structures.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Xiaohe Wang, Zengqiang Cao
Summary: This paper presents a dynamic installation (DI) method based on electromagnetic force to reduce damage to composite laminates and improve joint performance. The study shows that DI can effectively decrease installation resistance, reduce severe damage to laminates, and improve stress distribution in the joint.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Jitong Cui, Yingying Kong, Cuiwei Liu, Baoping Cai, Faisal Khan, Yuxing Li
Summary: This paper presents a method for quantifying the failure probability of hydrogen doped pipelines and utilizes Bayesian network for quantitative calculation. The results show that this method can more accurately assess the failure probability of hydrogen doped pipelines and provide a decision basis for preventing failure accidents.
ENGINEERING FAILURE ANALYSIS
(2024)
Article
Engineering, Mechanical
Yiping Jiang, Maoru Chi, Jungang Yang, Liangcheng Dai, Yuchen Xie, Zhaotuan Guo
Summary: This article investigates and simulates the derailment of empty freight trains at the switch section of a turnout in the diverging route, and proposes preventive measures. The results show that the derailment is caused by the combined effect of various factors, and reducing the longitudinal coupler force and the wheel rail friction coefficient can decrease the possibility of derailment. Additionally, installing a guard rail in front of the turnout can effectively prevent derailment.
ENGINEERING FAILURE ANALYSIS
(2024)
