Article
Engineering, Mechanical
Jairan Nafar Dastgerdi, Omid Jaberi, Heikki Remes
Summary: This paper introduces a new method for characterizing additive manufactured stainless steel samples using XCT, which provides holistic information and predicts fatigue life and failure origins.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Waqas Muhammad, Jidong Kang, Kaan Inal
Summary: The fatigue behavior of AlSi10Mg alloy processed by laser-based powder bed fusion of metals (PBF-LB/M) in different conditions is evaluated. A new surface treatment method is applied to improve the fatigue strength of the alloy. A simplified fracture mechanics-based fatigue life modeling approach is developed using real-time defects distribution data and surface profilometry measurements.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
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
Emre Akgun, Xiang Zhang, Romali Biswal, Yanhui Zhang, Matthew Dore
Summary: The failure of additive manufactured titanium alloy Ti-6Al-4V is primarily attributed to process-induced defects rather than pore size. Embedded pores below approximately 85 µm threshold size can achieve wrought level fatigue performance.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Klas Solberg, Even Wilberg Hovig, Knut Sorby, Filippo Berto
Summary: This study investigated the fatigue behavior of maraging steel grade 300 produced by laser beam powder bed fusion, focusing on surfaces built from both upward and downward directions. It was found that downward-facing surfaces had high surface roughness, while upward-facing surfaces had wavy surfaces. The fatigue behavior was found to be correlated with build orientation and surface roughness.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Materials Science, Multidisciplinary
Rachel Tullis, Anna Dunn, Dan Young, Nathan Klingbeil, Joy Gockel
Summary: Additive manufacturing allows for the creation of complex geometries by simultaneously fabricating the material and the component. In this study, the bulk processing parameters were modified during the fabrication of axial fatigue specimens, resulting in changes to both the microstructure and surface roughness. The axial fatigue testing revealed that surface roughness plays a significant role in fatigue initiation and has a greater influence on total life compared to differences in microstructures. Understanding the relationships between processing, structure, properties, and performance is crucial in additive manufacturing, including the interactions between different parameter sets and their effects on fatigue failure mechanisms.
Article
Engineering, Manufacturing
Litton Bhandari, Vidit Gaur
Summary: Additively manufactured Ti6Al4V alloys have high strength but suffer from poor ductility and inherent defects. This study investigates the influence of defects on mechanical and fatigue properties of the alloy and optimizes them through heat treatment.
ADDITIVE MANUFACTURING
(2022)
Article
Engineering, Mechanical
Federico Uriati, Gianni Nicoletto
Summary: This study investigates the anisotropic fatigue behavior of L-PBF Inconel 718 parts by using a novel method with miniature specimens and studying different process equipment. The results reveal the scatter in fatigue performance and provide guidance for the design of L-PBF Inconel 718 parts.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
S. Beretta
Summary: This paper discusses the fundamentals of extreme value statistics, its historical evolution, and its importance in applications to AM materials. It also highlights some open research issues that still need to be addressed.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Polymer Science
Irene Buj-Corral, Xavier Sanchez-Casas, Carmelo J. Luis-Perez
Summary: Fused filament fabrication (FFF) 3D printing technology allows for complex parts to be obtained at low cost and in reduced manufacturing times. This study focuses on the impact of main 3D printing parameters on roughness in curved surfaces. The results showed that roughness parameters were mainly influenced by layer height and nozzle diameter, and ANFIS models were used to analyze the data.
Article
Materials Science, Coatings & Films
Brodan Richter, Tim Radel, Frank E. Pfefferkorn
Summary: Poor fatigue life caused by rough and irregular surfaces is a significant challenge for additive manufacturing. Laser polishing, using a laser to irradiate, melt, and smooth the surface, is a solution. This study examines the laser polishing of cobalt-chromium samples produced through laser powder bed fusion. The influence of various laser processing parameters on surface smoothing is analyzed, with laser power playing the most important role. The starting surface condition and variability caused by particle adherence are also discussed. This work provides an important overview of processing aspects for advancing the commercialization of additive manufacturing technology in part finishing.
SURFACE & COATINGS TECHNOLOGY
(2022)
Article
Automation & Control Systems
Hossein Rezaeifar, Mohamed Elbestawi
Summary: This study focuses on the poor surface quality in the laser powder bed fusion (L-PBF) process and aims to minimize the surface roughness of the manufactured parts by using a feedforward plus feedback control system. The factors affecting surface quality were investigated through a monitoring system, and the desired melt pool width and critical spatter level were determined. An experimental model and control system were developed, and the performance was evaluated through simulations and experiments. The results showed a significant reduction in surface roughness and the ability to control the geometry of the melt pool to mitigate defects.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Engineering, Mechanical
T. Dusautoir, B. Berthel, S. Fouvry, P. Matzen, K-D. Meck
Summary: This study investigates the impact of post-processing treatments on the fatigue limit of additive manufactured Ti-6Al-4V under stress gradients, with a focus on surface integrity.
INTERNATIONAL JOURNAL OF FATIGUE
(2024)
Article
Automation & Control Systems
Soran Hassanifard, Kamran Behdinan
Summary: This study experimentally and numerically investigated the fatigue life of notched polylactic acid (PLA) samples fabricated using the fused deposition modeling (FDM) technique. The results showed that the raster orientation parameter had a significant impact on the fatigue strength reduction factors and fatigue lives. Samples with 90 degrees raster angles exhibited similar fatigue lives for notched and un-notched 3D-printed samples, while un-notched samples with 0 degrees raster orientations had higher fatigue lives compared to notched samples.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Ahmad Serjouei, Shukri Afazov
Summary: This work develops a predictive model for S-N curves that considers the effects of different metal laser-based additive manufacturing and post-processing technologies on fatigue behavior. The proposed model has been demonstrated to accurately capture the effects of induced defects and mean stress. It is valuable for fatigue assessment of AM 316L stainless steel and has the potential to be extended to other AM materials.
Article
Engineering, Mechanical
Zhuang Sun, Yixin Zhao, Yirui Gao, Sen Gao, Davide Elmo, Xindong Wei
Summary: In this study, the modified semi-circular bending test was used to investigate the fracture toughness of coal samples with different sizes and bedding angles. The results showed that the fracture toughness of coal exhibits size effect and anisotropy. The crack initiation and propagation in hydraulic fracturing of coal seam can be influenced by bedding angles.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Ruiming Zhang, Kai Ma, Wenzhu Peng, Jinyang Zheng
Summary: The fatigue crack growth rates of 4130X steel in different hydrogen concentrations were measured, and the influence of hydrogen on crack behavior was analyzed. Results show that the crack growth rate increases with increasing hydrogen pressure, reaching a threshold at 87.5 MPa.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Hien Do, Phuc L. H. Ho, Canh V. Le, H. Nguyen-Xuan
Summary: In this study, a new method for determining the limit loads of fracture structures using the pseudo-lower bound method with adaptive quadtree meshes is proposed. The method overcomes the volumetric locking problem and handles the challenge of hanging nodes during refinement procedure by using quadtree meshes. The effectiveness of the approach is demonstrated through numerical validation.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Weimin Song, Yuxin Fan, Hao Wu, Liang Zhou
Summary: This study proposed a novel test method to characterize the I-II mixed fracture toughness of asphalt pavement and investigated the effects of reclaimed asphalt pavement (RAP) and loading rate. The results showed that loading rate and inclusion of RAP had positive effects on fracture toughness.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Zida Liu, Diyuan Li, Jianqiang Xia, Quanqi Zhu
Summary: In this study, the influence of flaw inclinations on the failure mechanism of fissured granite specimens was analyzed through a series of experiments. A quantitative method combining deep learning and scanning electron microscope was employed to identify the mesoscopic fracture mechanism of macroscopic cracks. The results indicated that the failure of fissured specimens was mainly caused by tensile stress and shear stress.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Jiabing Zhang, Yiling Chen, Ronghuan Du, Xianglian Zhao, Jun Wu
Summary: This study investigated the mechanical characteristics and crack propagation behavior of sandstone-like samples with single cracks under freeze-thaw cycles. The results demonstrated the significant effects of crack angle and freeze-thaw cycles on the compressive strength and stability of the samples. Confining pressure inhibited the freeze-thaw deterioration, and the acoustic emission signals exhibited good consistency with the stress-strain curves. The simulation results matched well with the experimental results, and five crack propagation modes were proposed.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Felix Boedeker, Pauline Herr, Anders Biel, Ramin Moshfegh, Stephan Marzi
Summary: Cohesive Zone Models with finite thickness are widely used for fracture mechanical modeling. Computational homogenization techniques are crucial for the development of advanced engineering materials. FFT-based homogenization scheme shows potential in reducing computational effort and has practical applications.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Sobhan Pattajoshi, Sonalisa Ray, Yugal Kishor Joshi
Summary: In this work, a novel multi-layer composite structure is proposed for protective shelter design. The dynamic behavior and mechanical performance of the multi-layer composite under projectile impact loading are investigated. The proposed composite target demonstrates enhanced penetration resistance and lesser damage compared to its reinforced concrete monolayer counterpart. An analytical model is also developed to predict the forces transmitted to the lowest layer for design purposes.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
H. M. Shodja, M. T. Kamali, B. Shokrolahi-Zadeh
Summary: This study proposes a semi-analytical method for calculating the stress intensity factor of an internally pressurized eccentric annular crack. By using hypersingular integral equations and conformal mapping, accurate values of SIFs along the crack edges can be obtained. The material properties of the elastic matrix do not affect the SIF values, as demonstrated through the investigation of geometric parameters.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Wen Hua, Zhanyuan Zhu, Wenyu Zhang, Jianxiong Li, Jiuzhou Huang, Shiming Dong
Summary: Accurate assessment and prediction of fracture behavior in cracked materials using mixed mode fracture criteria are crucial in fracture mechanics. This study comprehensively reviewed modified fracture criteria that incorporate T-stress for mixed mode I-II cracks. A comparative analysis was conducted between experimental results and theoretical predictions for five different cracked configurations. The study also discussed the effect of T-stress on crack initiation angle and fracture toughness, providing suggestions. The results showed variations in predictive accuracy across different cracked configurations due to disparities in T-stress. However, similar predictions were observed for semi-circular bend and edge-crack triangular specimens due to their similar biaxial stress ratio B. Different fracture criteria were suitable for different cracked configurations with positive or negative T-stresses.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Qing-qing Shen, Qiu-hua Rao, Wei Yi, Dian-yi Huang
Summary: This study proposes a theoretical approach to forecast multi-crack propagation trajectories in a finite plate. By calculating the stress intensity factor (SIF) and analyzing the influence of crack size, the criteria for crack initiation and propagation in a finite plate are established. Experimental results demonstrate that the SIF of multiple cracks in a finite plate is consistently larger than that of an infinite plate.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Songbai Li, Qiyun Zhu, Zhizhong Lu, Hongzhi Yan, Chu Zhu, Peize Li
Summary: This study investigates the effects of laser heating and laser shot peening on fatigue life of AA2524, and predicts the fatigue life using artificial neural networks and support vector regression models. The results show that laser heating and laser shot peening can significantly improve the fatigue life, and the neural networks have better prediction ability.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
V. Shlyannikov, A. Sulamanidze, D. Kosov
Summary: This paper presents experimental crack-growth data for thermomechanical fatigue conditions in nickel-based alloy components. The crack-growth experimental results are interpreted using finite element analyses and multi-physics numerical calculations. The results show that crack growth rate is slower under isothermal pure fatigue conditions, while it is faster under thermomechanical cyclic deformation conditions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Tairui Zhang, Xin Ma, Bin Yang, Wenchun Jiang, Zhiqiang Ge, Xiaochao Liu
Summary: This study experimentally investigated the fracture toughness distributions in dissimilar metal welds. The predictions of fracture toughness were made using three criteria and an energy release rate model. The results showed that using the critical strain criterion and ERR model resulted in higher consistency compared to mini-CTs, while the predictions using the critical stress criterion had high dispersion. The study also investigated the source of errors through damage developments and SEM observations.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Yike Dang, Zheng Yang, Xiaoyu Liu, Jianghao Guo
Summary: This study uses discrete element modeling to examine bedded rock failure with parallel defects. It is found that bedding influences crack propagation direction but has limited impact on final failure. Shear failure accumulates at the bridge area and defect tip, while tensile failure occurs during nucleation region development.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)