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
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
M. Moattari, M. M. Shokrieh, H. Moshayedi
Summary: The present study focuses on investigating the influence and interaction of crack-tip geometrical constraints and welding residual stresses (WRS) on fracture behavior of IN939 superalloy. Results show that geometrical constraints have a more evident impact on WRS. Unexpected fracture behavior may occur when the WRS changes from tensile to compressive near the crack tip.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Di Xie, Wei Zhang, Zongyang Lyu, Peter K. Liaw, Huy Tran, Huck Beng Chew, Yujie Wei, Yang Ren, Yanfei Gao
Summary: Despite the superior mechanical properties of magnesium alloys, their potential applications are limited due to a lack of understanding of their failure mechanisms. This study utilizes synchrotron X-ray diffraction technique to analyze in situ strain mapping in a highly textured ZK60 Mg alloy. The results show good agreement with micromechanical modeling and reveal localized twin activities near the fatigue crack.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Materials Science, Multidisciplinary
Chengyang Mo, Jordan R. Raney, John L. Bassani
Summary: In this study, a crack terminating at an arbitrary angle to the interface between two neo-Hookean sheets was investigated under plane stress conditions using finite deformation theory. The asymptotic crack-tip deformation and stress fields were analyzed with respect to the ratio of moduli and crack angle relative to the interface. A stretch-based crack growth criterion was developed to predict the delay of crack growth through bi-material interface, and could be extended to any heterogeneity and material based on experimental validation.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mechanics
Seung-Ho Lee, Hyun-Woo Jung, Yun-Jae Kim, Kamran Nikbin, Robert A. Ainsworth
Summary: This study analyzes 316H creep crack growth data at 550 degrees C to investigate the effect of inplane constraint on creep crack initiation times. A constraint parameter is proposed to quantify the difference between actual opening stress and the Riedel-Rice opening stress field, using experimentally measured C*. The analysis shows that creep crack initiation times can be well characterized by the C* integral with the proposed parameter, and a modified model suggests a reduction in scatter in predictions from -40 to -5.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Chemistry, Physical
Xiaoyu Zheng, Qi Huang, Hong Mao, Kai Li, Namin Xiao, Xingwu Li, Yong Du, Yuling Liu, Yi Kong
Summary: This study develops a single-crystal strength model including precipitate enhancement effects and applies it to the mechanical simulation of Al-Mg-Si alloy. The simulation results agree well with experimental results, indicating the realistic physical implications of the model. The study also suggests that different precipitate phases should be separately considered when simulating the mechanical response of Al-Mg-Si alloy.
Article
Mechanics
Meiling Xu, Huang Yuan
Summary: This study investigates the crack-tip stress fields of elastoplastic fatigue crack growth with crack closure and their correlation to the Delta J-integral. The computational results show that the singularity of the effective stress ranges during the opening process decreases with increasing crack closure, while the effective stress ranges during the closing process follow the HRR solution form. The farfield Delta J(eff)-integral is proposed to characterize the stress at the crack tip during the closing process, which is independent of the loading ratio and the path dependence of the Delta J-integral. The proposed estimation formula for the effective Delta J(eff)-integral is applicable to different loading ratios and plastic hardening materials based on extensive FEM computations. The in-plane constraint effects in fatigue crack growth can be quantified using the J - Q concept of elastoplastic fracture mechanics within the framework of Delta J(eff)-Q characterization.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Yanwei Dai, Fei Qin, Yinghua Liu, Haofeng Chen
Summary: In this paper, the material mismatch effect on the interface creep crack tip field is studied. It is found that the material mismatch constraint effect decreases with the increase of the local mismatch factor.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Materials Science, Multidisciplinary
K. H. Leong, F. Yusof
Summary: The study found that the thickness affects the crack tip constraint of deep and shallow cracks by changing the shape of the plastic zones and the normal stresses at the crack tip. Increasing thickness while maintaining the ratio of B/(W-a) leads to a marginal increase in normal stresses at the crack tip and reduction in toughness of the shallow cracked geometries.
INTERNATIONAL JOURNAL OF FRACTURE
(2021)
Article
Materials Science, Multidisciplinary
Rakesh Kumar, Dhiraj K. Mahajan
Summary: In this study, a coupled framework of dislocation density-based crystal plasticity model and slip-rate based hydrogen transport model is developed to simulate hydrogen-assisted damage at the deforming crack-tip. The evolving hydrogen concentration is accounted for by chemical potential-based boundary conditions and mobile dislocation-assisted hydrogen transport. A novel fracture indicator parameter is proposed to quantify the damage, considering the combined effect of local hydrogen concentration, accumulated plastic slip, and stress triaxiality. Depending on the crystal orientation, the damage is shown to be associated either with an individual hydrogen embrittlement mechanism (hydrogen-enhanced localized plasticity and hydrogen-enhanced decohesion) or their synergistic effect at the crack tip.
MECHANICS OF MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Subhendu Chakraborty, Somnath Ghosh
Summary: This paper presents a method for enhancing the Helmholtz free energy density functionals in coupled crystal plasticity phase-field finite element models of fracture by considering the influence of atomic-scale, crack-tip nucleated dislocations. The proposed approach is motivated and calibrated by energy equivalence between atomistic-continuum scale models, demonstrating the significant effect of nucleated dislocations on crack evolution.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Mechanics
Soheil Niknafs, Mohammad Silani, Franco Concli, Ramin Aghababaei
Summary: This paper introduces a concurrent multiscale method for modeling crack propagation, which combines the continuum finite element domain with a coarse-grained atomistic potential. This method effectively captures crack formation while reducing computational costs.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Mechanics
Soheil Niknafs, Mohammad Silani, Franco Concli, Ramin Aghababaei
Summary: This paper introduces a novel method for modeling crack propagation in brittle solids, by coupling the continuum finite element domain with coarse-grained atomistic potential to suppress dislocation nucleation, thereby increasing computational efficiency.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Engineering, Mechanical
Wanjia Li, Shigeru Hamada
Summary: The determination of the transition point from crack length to a microstructurally small crack is crucial for predicting crack extension behavior. The conventional probabilistic criterion of crack length smaller than the grain size does not consider the discrepancy in metal's crystallite plasticity property. To address this, the authors propose a deterministic method based on crystallite plasticity to judge microstructurally small cracks using a physics-based crystal plasticity finite element model. The method utilizes the difference in crack tip opening displacement with the change in the ratio between crack length and grain size and the variation in grain orientation ahead of the crack tip. The case study on copper demonstrates the effectiveness of the proposed method in defining microstructurally small cracks.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
