Engineering Fracture Mechanics最新文献

{"title":"Mesh-independent proportional method to obtain ISSF and singularity index at the interface corner of three-dimensional dissimilar structures","authors":"Tatsujiro Miyazaki ,&nbsp;Hibiki Fukuda ,&nbsp;Nao-Aki Noda","doi":"10.1016/j.engfracmech.2024.110624","DOIUrl":"10.1016/j.engfracmech.2024.110624","url":null,"abstract":"<div><div>An efficient analysis method is proposed for the intensity of singular stress field (ISSF) as well as the singularity index (SI) at the interface corner of three dimensional (3D) bonded joints by using the finite element method (FEM). By varying the minimum mesh size <span><math><mrow><msub><mi>e</mi><mrow><mi>m</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow></math></span>, the FEM stresses <span><math><mrow><msub><mi>σ</mi><mrow><mi>FEM</mi></mrow></msub></mrow></math></span> obtained from the FEM are investigated around the corner singular point. Then, mesh-independent expressions such as <span><math><mrow><msub><mi>σ</mi><mrow><mi>FEM</mi></mrow></msub><mrow><mfenced><mrow><mi>r</mi></mrow></mfenced></mrow><mo>·</mo><msup><mrow><mfenced><mrow><msub><mi>e</mi><mrow><mi>m</mi><mi>i</mi><mi>n</mi></mrow></msub></mrow></mfenced></mrow><mrow><mn>1</mn><mo>-</mo><mi>λ</mi></mrow></msup><mo>=</mo><mi>c</mi><mi>o</mi><mi>n</mi><mi>s</mi><mi>t</mi><mo>.</mo></mrow></math></span> are derived for ISSF and SI based on the proportional stress fields in prismatic joints having similar FEM mesh pattern. Previously analyzed results coincide with the present mesh-independent results to the three digits for ISSF and SI in 3D corners. The experimental results show that the critical singular stress distributions causing debonding are almost identical at the interface corner and at the interface edge independent of the adhesive thickness. This is confirmed for the ABA joint denoting the 3D prismatic butt joints whose similar adherends A are bonded by resin B. Under a constant load, the ABC joint whose dissimilar adherends A and C are bonded by resin B has larger ISSF than the ABA joints. This ISSF difference increases with decreasing the adhesive thickness <span><math><mrow><mi>h</mi></mrow></math></span>, and this ISSF difference is more remarkable at the interface corner than at the interface edge. The debonding failure criterion is discussed by using the previous experiment conducted for ABA-, ABC-butt joints and ABA-, ABC- three step lap joints. It is found that the adhesive strength of the ABC joint can be expressed as a constant critical ISSF at the interface corner and the constant value coincides with the value of the 3D ABA joints. Those new findings show that the proposed 3D mesh-independent proportional method is especially useful for evaluating the debonding strength of the adhesive ABC joints.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110624"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165260","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":"Adaptive phase-field modeling of fracture propagation in layered media: Effects of mechanical property mismatches, layer thickness, and interface strength","authors":"Salman Khan ,&nbsp;Ishank Singh ,&nbsp;Chandrasekhar Annavarapu ,&nbsp;Antonio Rodríguez-Ferran","doi":"10.1016/j.engfracmech.2024.110672","DOIUrl":"10.1016/j.engfracmech.2024.110672","url":null,"abstract":"<div><div>Fracture propagation in layered media is investigated using an adaptive phase-field method. We focus on the interplay between cracks and interfaces, considering both perfectly and imperfectly bonded interfaces. For perfectly bonded interfaces, three-layer models are analyzed to study the effects of mechanical property mismatches, layer thickness, and confinement pressure on crack growth. Results reveal that critical energy release rate mismatch significantly influences the crack geometry, leading to single through-going fractures, middle layer fragmentation, or delamination. There is an inverse relationship between layer thickness and fragmentation, and between confinement pressure and delamination. For imperfectly bonded interfaces, a phase-field method incorporating an interface energy term is introduced and validated with benchmark examples. This model is used to study the combined effects of mechanical property mismatch and interface strength on crack growth. Our findings demonstrate that the interface strength strongly influences the dominant failure mechanism, with high strength favoring mechanical property mismatch-driven fracture and low strength leading to interfacial failure. Finally, the robustness of the proposed method is illustrated through a complex seven-layer model. This study provides valuable insights into the various factors influencing macroscopic failure mechanisms in layered materials.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110672"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165921","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":"Numerical analysis of a phase field model for ductile fracture phenomena","authors":"Aris Tsakmakis,&nbsp;Michael Vormwald","doi":"10.1016/j.engfracmech.2025.110859","DOIUrl":"10.1016/j.engfracmech.2025.110859","url":null,"abstract":"<div><div>In fracture mechanics, phase field theories have been introduced for the first time for brittle materials, in order to regularise the sharp crack topology. Especially, the crack surface part of the total energy functional is regularised by using a phase field variable. In the present work, a phase field model for ductile fracture in the framework of non-conventional thermodynamics is studied. In contrast to brittle fracture, the physical mechanisms for fracture are supposed to be driven by plastic deformation.</div><div>The aim of the paper is to highlight, by analysing numerical examples, important features of the model that affect the predicted material responses. The analysis refers to assumptions commonly adopted in phase field theories and continuum damage mechanics and comprises the numerical robustness of the related finite element integrations.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"316 ","pages":"Article 110859"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379349","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":"Life evaluation method for nickel-based directionally solidified turbine blade-like specimens under near-service conditions","authors":"Tianxiao Sui ,&nbsp;Yang Gan ,&nbsp;Qinzheng Yang ,&nbsp;Shunpeng Zhu ,&nbsp;Wenjun Wang ,&nbsp;Dong Mi ,&nbsp;Zhengming Qian ,&nbsp;Xiaoan Hu","doi":"10.1016/j.engfracmech.2024.110787","DOIUrl":"10.1016/j.engfracmech.2024.110787","url":null,"abstract":"<div><div>Life assessment of turbine blades is a challenging issue due to the complexity of their structural designs and operational loads. To address the issue, a life evaluation method for turbine blade-like specimens under near-service conditions was investigated. First, creep and creep-fatigue tests were conducted on these specimens to replicate operational environments, with the nominal load of the critical section set at 950 °C/273 MPa. Next, the coupled-damage Norton-Bailey model was used to simulate the creep behavior at 760 °C, 850 °C and 980 °C. Electromagnetic-thermal coupling simulations were then carried out in COMSOL with a 120A alternating current, yielding the temperature distribution for the blade-like specimen. The mechanical response of these specimens under creep and creep-fatigue conditions was simulated based on the Norton-Bailey model. Finally, a life prediction model was developed by introducing a weight function into the critical distance method. The results indicated that the introduction of film-cooling holes and cyclic loading reduced the specimens’ life by 43 % and 42 %, respectively. Elevated temperatures (942–965 °C) at the leading edge caused crack initiation in non-holed specimens, while high stress (maximum stress of 1103 MPa) around the holes led to crack initiation in holed specimens. A comparative analysis with traditional cross-sectional averaging methods demonstrated that the proposed model achieves higher predictive accuracy, with all predictions falling within a twofold scatter band.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110787"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164580","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":"Testing and characterization of anisotropic plasticity of 6061-T6 aluminum alloy sheet: From in-plane to out-of-plane","authors":"Peihua Zhu ,&nbsp;Shitong Chen ,&nbsp;Qilin Zhang ,&nbsp;Yao Zhang ,&nbsp;Zhiyang Xie","doi":"10.1016/j.engfracmech.2024.110736","DOIUrl":"10.1016/j.engfracmech.2024.110736","url":null,"abstract":"<div><div>This paper presents material testing and characterization of anisotropic plasticity of 6061-T6 aluminum alloy rolled sheets. A total of 27 different specimen types are designed, considering various geometric configurations, sampling directions, and loading directions, including two newly developed out-of-plane specimens. Uniaxial tensile tests on smooth square bars oriented at different angles relative to the rolling direction are conducted to measure the material’s plastic strain ratios. The results reveal that the plastic volume of the aluminum alloy changes as plastic deformation progresses, challenging the conventional assumption of plastic incompressibility. Based on extensive experimental data, a new orthogonal anisotropic yield criterion is proposed. This criterion can fully characterize the transverse isotropy (i.e., in-plane isotropy and out-of-plane anisotropy), tension–compression asymmetry, and pressure-independent plastic properties of 6061-T6 aluminum alloy rolled sheets.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110736"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164997","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":"Corrigendum to “Quasi-static and intermediate test speed validation of SHPB specimens for the determination of mode I, mode II fracture toughness of structural epoxy adhesives” [Eng. Fract. Mech. 262 (2022) 108231]","authors":"P.D.P. Nunes ,&nbsp;E.A.S Marques ,&nbsp;R.J.C. Carbas ,&nbsp;A. Akhavan-Safar ,&nbsp;L.F.M da Silva","doi":"10.1016/j.engfracmech.2024.110752","DOIUrl":"10.1016/j.engfracmech.2024.110752","url":null,"abstract":"","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110752"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165251","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":"Utilizing controlled hydrogen-assisted pre-cracking to assess the fracture toughness of high-strength steels","authors":"Michael Brilz,&nbsp;Anutsara Chakamnan,&nbsp;Meike Szabo,&nbsp;Holger Hoche,&nbsp;Dimitar Damyanov,&nbsp;Marcus Klein,&nbsp;Matthias Oechsner","doi":"10.1016/j.engfracmech.2024.110742","DOIUrl":"10.1016/j.engfracmech.2024.110742","url":null,"abstract":"<div><div>The controlled initiation of detectable cracks is pivotal in fracture mechanics investigations. Typically, pre-notched specimens are utilized, and fatigue cracks are induced at the notch root. In the specific case of circumferentially notched tensile (CNT) specimens, fatigue cracks originate from rotating bending. Subsequently, the fatigue pre-cracked specimens undergo tensional fracture, and fracture toughness is ascertained based on the crack length and fracture stress. However, a notable portion of fatigue cracks initiated in this manner exhibits non-uniform radial lengths, leading to a ligament eccentricity relative to the fracture surface centre. Consequently, accounting for bending stresses alongside tensile stresses becomes imperative, which makes fracture mechanics testing methods more complex. In a previous study, the authors demonstrated that hydrogen-assisted cracking (HAC) can yield highly symmetric circumferential cracks in CNT specimens of high-strength quenched-tempered steel. In this context, the consistent circumferential formation of the crack, as well as the radial crack length are regulated by both the duration of hydrogen pre-charging and the subsequently applied preload. This paper elucidates the utility of hydrogen-induced circumferential cracks for evaluating fracture toughness. Both the fracture toughness in the presence of hydrogen (<span><math><msubsup><mi>K</mi><mrow><mi>Ic</mi></mrow><mi>H</mi></msubsup></math></span>) and the fracture toughness without the influence of hydrogen (<span><math><msub><mi>K</mi><mrow><mi>Ic</mi></mrow></msub></math></span>) are assessed reliably. For the latter, a hydrogen extraction heat treatment is carried out and the influence of the extraction temperature is discussed. By following this method, fracture toughness of CNT specimens can be reliably determined with simplicity, eliminating the need to consider bending stresses. This significantly enhances the usability of CNT specimens in fracture mechanics testing, which is why hydrogen-assisted pre-cracking is seen as a promising alternative to the established fatigue pre-cracking.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110742"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165253","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":"Evaluation of heat flux intensity factor for a V-notched structure by the isogeometric boundary element method","authors":"Feiyang Wang ,&nbsp;Changzheng Cheng ,&nbsp;Tengyue Li ,&nbsp;Jingwen Liu ,&nbsp;Zhilin Han","doi":"10.1016/j.engfracmech.2024.110681","DOIUrl":"10.1016/j.engfracmech.2024.110681","url":null,"abstract":"<div><div>The conventional boundary element method using piecewise polynomial interpolation cannot accurately simulate the singular heat flux field around the vertex of the V-notch. Herein, the singularity eigen-analysis combined with the isogeometric boundary element method is proposed to calculate the singular heat flux field. The V-notched structure is divided into two parts, in which one is the heat flux singularity sector near the vertex and the other is the remained structure without heat flux singularity. In the singularity sector, the asymptotic expansion of the heat flux is introduced to transform the heat conduction governing equation into ordinary differential eigen equation, from which the singularity orders and eigen angular functions can be determined, except for the amplitude coefficients in the asymptotic expansion. The boundary integral equations for the heat conduction analysis established on the remained structure are discretized by the non-uniform rational B-spline (NURBS) elements. The amplitude coefficients, which are corresponding to the heat flux intensity factors, can be yielded by coupling the isogeometric boundary integral equations with the singularity asymptotic expansion analysis. A coordinate system transformation method is then proposed to transform the heat conduction governing equations of orthotropic and anisotropic material into the one of the isotropic material, and the heat flux intensity factors are approved to be invariable before and after coordinate transformation. Since the NURBS elements are used, fewer elements are required to evaluate the heat flux intensity factors compared with the conventional boundary element method.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110681"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165302","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":"Investigation on the char crack growth of densified wood","authors":"Tianyang Chu ,&nbsp;Zhengyang Wang ,&nbsp;Shaorun Lin ,&nbsp;Chuangang Fan","doi":"10.1016/j.engfracmech.2024.110697","DOIUrl":"10.1016/j.engfracmech.2024.110697","url":null,"abstract":"<div><div>Densified wood (DW) is a novel engineering material with superior mechanical performance, but how its compact structure affects its char cracking behavior under fire remains unknown. This work experimentally and theoretically investigates the crack pattern and crack width of DW under radiative heating (<em>Q_r</em>). Longitudinal tensile facture-induced crack (L-crack) dominates the crack pattern due to its lower crack resistance (<em>C_t</em>). Delignification largely reduces the <em>C_t</em> of tangential tensile facture-induced crack (T-crack) resulting in more T-cracks observed on DW. Although DW has a lower <em>C_t</em> than natural wood (NW), its compact structure increases the cohesion among fibers, which increases the difficulty of the crack propagation. The crack width (<em>w_c</em>) growth rate increases with the increased <em>Q_r</em> and decreased wood density (<em>ρ</em>). Based on that, a dimensionless empirical correlation is proposed with an R2 of 0.853 to the measurement. Afterward, an analytical model, which considers the displacement due to the crack propagation in the T-L plane (<em>w_T-L</em>) and the L-R plane (<em>w_R-L</em>) and the displacement due to the shrinkage strain (<em>w_s</em>), is proposed to describe the crack width growth of L-crack<em>. w_T-L</em> and <em>w_s</em> are combined to dominate <em>w_c</em>. Both <em>w_T-L</em> and <em>w_R-L</em> decelerate with the increased <em>ρ</em>. The calculated <em>w_c</em> well-fits to the current and previous measurements indicating good accuracy and applicability. This work provide new insight into the understanding of the charring cracking of wooden materials and bio-materials.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110697"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165308","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":"Simulating concrete cracking and failure under impact loading using a novel constitutive integration paradigm in non-ordinary state-based Peridynamics","authors":"Xiaohu Yu ,&nbsp;Airong Chen ,&nbsp;Haocheng Chang","doi":"10.1016/j.engfracmech.2024.110703","DOIUrl":"10.1016/j.engfracmech.2024.110703","url":null,"abstract":"<div><div>Concrete cracking and failure under external loads are common in infrastructure, particularly under impact conditions where the variability of loads and the complexity of the cracking process present significant challenges. While the bond-based Peridynamic (BBPD) and Ordinary state-based Peridynamic (OSBPD) models are widely used in concrete damage analysis due to the low computational cost, their simple constitutive laws limit their effectiveness in simulating concrete’s response to impact loading. To overcome this limitation, we propose a novel approach that integrates classical constitutive models into the Peridynamics (PD) framework. Specifically, we reformulate the Concrete Damage Plasticity Model 2 (CDPM2) within a non-ordinary state-based PD (NOSBPD) framework, resulting in the CDPM2-PD model. This model incorporates factors such as strain rate effects and strain hardening and introduces a bond damage criterion for both tensile and compressive damage. Through three numerical examples, the CDPM2-PD model demonstrates its ability to accurately capture the cracking and failure process of concrete under impact, showing strong agreement with experimental observations in areas such as failure mode transitions and crack patterns. These results validate the model’s effectiveness and offer a versatile method for integrating classical constitutive models into the NOSBPD framework for complex material analysis.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110703"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165919","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}