Engineering Fracture Mechanics最新文献

{"title":"Numerical study of the effects of loading parameters on high-energy gas fracture propagation in layered rocks with peridynamics","authors":"","doi":"10.1016/j.engfracmech.2024.110516","DOIUrl":"10.1016/j.engfracmech.2024.110516","url":null,"abstract":"<div><div>The objective of this study is to investigate the influence of loading parameters on the propagation pattern of high-energy gas fractures in layered rock formations. To this end, a peridynamic model for brittle rock accounting for material heterogeneity was proposed. The ability of the model to simulate dynamic fractures was validated through laboratory experiments, and the homogeneity coefficient for the critical elongation rate was calibrated. On this basis, a numerical model of high-energy gas fracturing in layered rocks containing interfaces was constructed. Simulations were conducted to analyse high-energy gas fracturing from cylindrical intact boreholes and perforated boreholes under varying loading parameters. The results indicate that as the loading rate increases, the number of radial fractures surrounding the borehole gradually increases, whereas the influence of in-situ stress on fracture propagation diminishes. When the loading rate is fixed, both an increase in the peak pressure and a decrease in the decay rate are conducive to enhancing the propagation length of fractures. The propagation speed of fractures significantly decreases when they reach an interface but recovers after they penetrate it. Fractures tend to penetrate an interface when the angle of approach is closer to a right angle, and the direction of fracture propagation can be controlled through a perforation design. These findings provide valuable insights into the selection and optimization of loading parameters for reservoir stimulation via high-energy gas fracturing.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mechanism and prevention of rockburst induced by the instability of the composite hard-roof coal structure and roof fractures","authors":"","doi":"10.1016/j.engfracmech.2024.110512","DOIUrl":"10.1016/j.engfracmech.2024.110512","url":null,"abstract":"<div><div>Despite the implementation of prevention and control measures, rockburst still occur. The characteristics of composite coal were analyzed by combining monitoring and early warning means. Two types of composite coal in the hard roof were distinguished based on their distinct initiation and destruction processes despite experiencing the same rockburst event. Rockburst caused by structural instability was studied in different mining stages, and the following conclusions were considered. 1) The mechanical model of the instability of composite coal in hard roof was established for different mining stages to reveal rockburst mechanisms. The high-speed advance of working faces changed the fractured structure of upper hard rocks in the pressure-relief protection range. The sudden fracture of long cantilever structures caused dynamic load disturbance to high-stress coal, which resulted in rockburst in the insufficient mining stage. The failure and deformation of coal under high-stress static loads created conditions for the instability and fractures of roof. The disturbance of low hard rock strata aggravated the deformations of damaged coal. Therefore, rockburst appeared in the full mining stage. 2) Structural instability and roof fracture caused by different factors were the main causes of rockburst for composite coal in hard roof in different mining stages. Relevant prevention and control measures were formulated to ensure the safety of working faces, which provided references for the prevention and control of rockburst in working faces under similar conditions.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A probabilistic model to predict specimen geometry effects on fracture toughness in ferritic–pearlitic steels","authors":"","doi":"10.1016/j.engfracmech.2024.110493","DOIUrl":"10.1016/j.engfracmech.2024.110493","url":null,"abstract":"<div><div>This work describes a probabilistic framework for cleavage fracture of ferritic–pearlitic steels incorporating experimental measurements of microcrack distribution associated with the cracking of the pearlitic microstructure. A central objective of this study is to explore and further extend application of a probabilistic framework incorporating the statistics of microcracks to predict specimen geometry effects on the fracture toughness distribution for a typical ferritic–pearlitic structural steel. Fracture toughness values for an ASTM A572 Grade 50 structural steel derived from fracture tests using conventional SE(B) specimens with varying thickness and <span><math><mrow><mi>a</mi><mo>/</mo><mi>W</mi></mrow></math></span>-ratios provide the cleavage fracture resistance data needed to assess specimen geometry effects on the probability distribution of <span><math><msub><mrow><mi>J</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>-values. The present exploratory study successfully predicts the measured statistical distribution of cleavage fracture toughness in shallow crack specimens and provides further support of the proposed probabilistic model as a more advanced and effective engineering-level procedure in fracture assessment methodologies.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tensile fracture prediction of 3D-printed V-notched PLA specimens: Application of VIMC-MEMC in conjunction with brittle fracture criteria","authors":"","doi":"10.1016/j.engfracmech.2024.110497","DOIUrl":"10.1016/j.engfracmech.2024.110497","url":null,"abstract":"<div><div>This study investigates the fracture behavior of additively manufactured round-tip V-notched diagonally loaded square plate (RV-DLSP) specimens with different notch opening angles and tip radii produced from the Polylactic acid (PLA) with <span><math><msub><mrow><mo>[</mo><mn>0</mn><mo>/</mo><mn>90</mn><mo>/</mo><mn>45</mn><mo>/</mo><mo>-</mo><mn>45</mn><mo>]</mo></mrow><mi>s</mi></msub></math></span> raster orientation using the fused deposition modeling (FDM) technique. PLA is known for its ductile behavior, making it a suitable material for various engineering applications. Also, the layer-wise manufacturing process in FDM technique makes the PLA specimens be actually anisotropic. To take the nonlinearity and anisotropy of PLA simultaneously into consideration in prediction of the fracture loads of RV-DLSP specimens, the present study employs the Virtual Isotropic Material Concept (VIMC) and modified Equivalent Material Concept (MEMC) in a two-level strategy of simplifying PLA to an isotropic linear elastic virtual material. Then, the mean stress (MS) and maximum tangential stress (MTS) criteria are utilized to estimate the fracture loads. The theoretical estimations reveal that the VIMC-MEMC-RV-MS criterion is the most accurate model, demonstrating its effectiveness in predicting the fracture behavior of RV-DLSP specimens. Additionally, the VIMC-MEMC-RV-MTS criterion shows commendable accuracy, particularly for the specimens with 30 (deg.) notch opening angle. The scanning electron microscopy (SEM) analysis of the fracture surfaces provides further insights into the fracture mechanisms of RV-DLSP specimens. Notably, distinct fracture patterns are observed based on variations in the notch geometry. Specimens with smaller notch tip radii exhibit fiber cleavage, while those with larger radii display greater fiber interpenetration. These SEM observations are consistent with the fracture load data, which indicates higher fracture loads with increasing the notch opening angle and tip radius. By integrating VIMC and MEMC with the two fracture criteria, accurate predictions of the notch fracture toughness can be achieved, facilitating the design and optimization of 3D-printed PLA components against fracture.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An interprocess communication-based two-way coupling approach for implicit–explicit multiphysics lattice discrete particle model simulations","authors":"","doi":"10.1016/j.engfracmech.2024.110515","DOIUrl":"10.1016/j.engfracmech.2024.110515","url":null,"abstract":"<div><div>In this study, the researchers have developed a Multiphysics-Lattice Discrete Particle Model (M-LDPM) framework that deals with coupled-fracture-poroflow problems. The M-LDPM framework uses two lattice systems, the LDPM tessellation and the Flow Lattice Element (FLE) network, to represent the heterogeneous internal structure of typical quasi-brittle materials like concrete and rocks, and to simulate the material’s mechanical and transport behavior at the aggregate scale. The researchers revisited the LDPM governing equations and added the influence of fluid pore pressure. They also derived the Flow Lattice Model (FLM) governing equations for pore pressure flow through mass conservation balances for uncracked and cracked volumes. The M-LDPM framework was implemented using Abaqus user element subroutine VUEL for the explicit dynamic procedure of LDPM and user subroutine UEL for the implicit transient procedure of FLM. The coupling of the two models was achieved using Interprocess Communication (IPC) between Abaqus solvers. The M-LDPM framework can simulate the variation of permeability induced by fracturing processes by relating the transport properties of flow elements with local cracking behaviors. The researchers validated the M-LDPM framework by comparing the numerical simulation outcomes with analytical solutions of classical benchmarks in poromechanics.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural fatigue crack propagation simulation and life prediction based on improved XFEM-VCCT","authors":"","doi":"10.1016/j.engfracmech.2024.110519","DOIUrl":"10.1016/j.engfracmech.2024.110519","url":null,"abstract":"<div><div>To simulate structural crack propagation and predict fatigue life, the extended finite element method (XFEM) combined with the virtual crack closure technique (VCCT) is adopted in this paper. Firstly, the underlying principles of the XFEM-VCCT framework are elaborated comprehensively, mainly including the calculation of crack tip energy release rate based on VCCT, the simulation of element cracking utilizing the phantom nodes, and the computation of structural responses under cyclic loading through the direct cyclic analysis. In addition, to calculate the crack propagation length, an interpolation method to obtain the crack tip coordinates is developed based on tracking and locating the crack by the level set functions. Meanwhile, to compensate the defect that the fatigue life is often overestimated when dealing with the complex mode crack in complex structure through XFEM-VCCT, a simple improved algorithm based on the average rate concept is proposed without altering the XFEM-VCCT framework. Based on specific examples, the necessity and accuracy of the improved algorithm are fully verified by comparing with the original method, and the fatigue life predicted by the improved algorithm is more consistent with reality. Finally, this method is successfully applied to the simulation and analyses for a typical ship stiffened plate structure, demonstrating good engineering applicability.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic fracture toughness and crack propagation mechanism of a heterogeneous heterostructured material under combined strengthening mechanisms","authors":"","doi":"10.1016/j.engfracmech.2024.110508","DOIUrl":"10.1016/j.engfracmech.2024.110508","url":null,"abstract":"<div><div>Developing fracture-resistant high-strength steels is an attractive prospect for various structural applications. In this work, a combination of carburizing heat treatment (CHT) and shot peening (SP) was used to develop combined strengthening (CS) mechanisms and to improve the mechanical strength and dynamic fracture toughness of 18CrNiMo7-6 alloy steel. Standard tensile tests and split Hopkinson pressure bar tests were conducted to investigate the strength and dynamic fracture toughness of the 18CrNiMo7-6 alloy steel. The crack initiation and propagation of samples were studied using scanning electron microscopy and transmission electron microscopy. Microstructure characterization and molecular dynamic simulations indicated that the excellent dynamic fracture toughness of the CS samples could be attributed to the grain refinement after strengthening and the formation of numerous slip bands at the crack tips, reducing the stress concentration at the crack tips. The Cr₂₃C₆ precipitates have a positive effect on the strength improvement of 18CrNiMo7-6 alloy steel. The results showed that this research can be used to guide the design of steels with high-strength and high-dynamic fracture toughness.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multiscale modeling for progressive failure behavior of unidirectional fiber-reinforced composites based on phase-field method","authors":"","doi":"10.1016/j.engfracmech.2024.110517","DOIUrl":"10.1016/j.engfracmech.2024.110517","url":null,"abstract":"<div><div>The effective macroscopic properties of composites are determined by the intricate interactions among the individual components within their microstructure. Preserving these microscopic details during the failure simulation of macrostructures presents significant challenges. This work proposes a multiscale modeling framework to numerically predict the macroscopic fracture properties of unidirectional fiber-reinforced composites based on micromechanical analysis. In this study, 2D representative volume elements (RVEs) combined with the phase-field method are utilized to simulate fiber-reinforced composites under transverse loadings. A series of representative loading conditions are employed to investigate cracking patterns and to construct failure strength envelopes of the composites subjected to different multiaxial proportional loadings. By extracting the softening curve from the uniaxial tensile simulation of the RVE and fitting it with a tenth-order polynomial, the homogenized cohesive law, combined with the phase-field method, is applied to the damage analysis of macroscopic heterogeneous materials. The homogenized model of unidirectional fiber reinforced composites is numerically validated through simulations of a 2D flat plate. The simulation results demonstrate the excellent potential of the proposed multiscale modeling framework to accurately and efficiently predict the progressive failure and fracture behavior of fiber-reinforced composites in engineering applications.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mode II fracture behavior of glass fiber composite-steel bonded interface–experiments and CZM","authors":"","doi":"10.1016/j.engfracmech.2024.110510","DOIUrl":"10.1016/j.engfracmech.2024.110510","url":null,"abstract":"<div><div>The dominant failure mode was characterized as debonding in the novel non-welded wrapped composite joint made with GFRP composites wrapped around steel sections. Glass fiber composite-steel three-point end notched flexure (3ENF) and four-point end notched flexure (4ENF) specimens were utilized to experimentally investigate mode II fracture behavior of this composite-steel bonded interface. Two new methods were proposed with the help of digital image correlation (DIC) technique to quantify fracture data during the tests: 1) the “shear strain scaling method” to quantify the crack length <em>a</em>; 2) the asymptotic analysis method based on the longitudinal displacement distribution along the height of the specimen at the pre-crack tip to quantify the crack tip opening displacement (CTOD). To numerically simulate the mode II fracture behavior, a four-linear traction-separation law was proposed in the cohesive zone modeling (CZM) where the softening behavior with a plateau was defined by the authors between traditionally considered initiation and fiber bridging behavior. The experimental and numerical approaches were validated mutually through good matches between the test and FEA results. 3ENF test provided good insight into softening behavior while 4ENF contributed to quantification of fiber bridging. These findings contribute to a more comprehensive characterization and understanding of the ductile fracture behavior of bi-material bonded joints, especially in mode II failure scenarios.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0013794424006738/pdfft?md5=0ce5a0fec68ab83fe6fd12e2ef2c1995&pid=1-s2.0-S0013794424006738-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The peeling behavior of film/substrate systems with periodic and discontinuous bonding","authors":"","doi":"10.1016/j.engfracmech.2024.110518","DOIUrl":"10.1016/j.engfracmech.2024.110518","url":null,"abstract":"<div><div>Discontinuous bonding is a common adhesion state in multilayer structures within the shipbuilding, automotive, and semiconductor industries, as well as in biological adhesion. Based on the cohesive theory and the Euler-Bernoulli beam model, we investigate the peeling behavior of a film from the rigid substrate subjected to periodic and discontinuous bonding. Different from the continuous bonding model, the peeling force during the peeling process exhibits repeated fluctuations. The increase and decrease of peeling force correspond respectively to the initiation of cohesive zones within the non-bonded and bonded segments. Furthermore, the bonding state at the crack tip influences the change pace of the energy release rate. Specifically, when the cohesive zone initiates within a bonded segment, the decrease in the energy release rate accelerates noticeably as the crack tip enters a non-bonded segment. Additionally, the influence of diverse bonding ratios and varying periodic lengths is discussed. This paper provides insights into the peeling behavior under discontinuous bonding effects in nature, and offers potential applications for the optimization and design of multilayer structures.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":4.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}