{"title":"Failure criterion for thread-like fibers in a thermoelastic medium","authors":"Oleh Yashiy , Andrii Korniichuk , Iryna Didych , Dmytro Tymoshchuk , Iaroslav Pasternak","doi":"10.1016/j.prostr.2025.06.032","DOIUrl":"10.1016/j.prostr.2025.06.032","url":null,"abstract":"<div><div>The paper introduces fracture criteria for thermoelastic solids containing deformable thread-like inhomogeneities. It revisits previously introduced models of these inhomogeneities, which reduce the problem to studying specific influence functions distributed along a spatial curve. This approach reduces the number of degrees of freedom in the problem and provides a more compact solution. The paper focuses on the fracture behavior of such inhomogeneous materials under three distinct mechanisms: (a) fracture of the inhomogeneity, (b) its debonding, and (c) fracture initiation near its tip. The mathematical formulations for these criteria are provided, and numerical results are presented.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 126-131"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Josef Arthur Schönherr , Falk Mueller , Christian Kontermann , Matthias Oechsner
{"title":"Evaluation of the C* Parameter in Welded Joints of 9%Cr Steels Under Consideration of the Heat Affected Zone","authors":"Josef Arthur Schönherr , Falk Mueller , Christian Kontermann , Matthias Oechsner","doi":"10.1016/j.prostr.2025.06.077","DOIUrl":"10.1016/j.prostr.2025.06.077","url":null,"abstract":"<div><div>In fracture mechanics based component assessment of parts containing microstructural defects subjected to elevated temperatures, the <em>C</em>* parameter is a common choice for describing the crack tip loading under steady-state creep conditions. Welded joints of ferritic-martensitic 9%Cr steels, commonly used in applications of up to 650°C operation temperature, comprise a rather complex and inhomogeneous microstructure in the heat affected zone, with wildly differing creep properties in comparison to the base materials. Therefore, the influence of the inhomogeneous material must be considered carefully when calculating <em>C</em>*. This paper is subjected to the evaluation of the <em>C</em>* parameter in compact tension fracture mechanics specimens for a welded joint made from two different 9%Cr steels with an additional buttering. Based on finite element simulations, different methods for calculating <em>C</em>* are assessed. It is shown that the application of methods disregarding the properties of the heat affecting zone leads to erroneous results.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 425-431"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improvement In Fatigue Properties Of Welded Joints Using Crack Initiation Resistant Steel Part2:Fatigue Crack Initiation Life Of Rib-To-Deck Welded Joints Of Orthotropic Steel Bridge Decks","authors":"Akito Tabata , Masahiro Matsushita , Tetsuo Yamaguchi , Yasuhito Takashima , Toshiyuki Ishikawa","doi":"10.1016/j.prostr.2025.06.075","DOIUrl":"10.1016/j.prostr.2025.06.075","url":null,"abstract":"<div><div>Fatigue durability is one of the problems in the maintenance of bridges. One of the areas of concern for fatigue crack initiation, the weld between the U-shaped rib and the deck of Orthotropic Steel Decks is known. The fatigue crack initiation life of a rib - to - deck welded joints was investigated using a developed steel with high crack initiation resistance. As a result, when the developed steel was used for the deck, the crack initiation life was prolonged by about 1.5 times compared with the case where the conventional steel was applied.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 415-419"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High Temperature Fracture Toughness Tests on P91 Steel for Fusion Applications","authors":"A.F Perez , T.F. Calvet , Y. Wang , C.M. Davies","doi":"10.1016/j.prostr.2025.06.079","DOIUrl":"10.1016/j.prostr.2025.06.079","url":null,"abstract":"<div><div>Steels used in fusion reactors must maintain structural integrity and safety under extreme conditions, including high temperatures and 14MeV neutron irradiation. Fracture toughness is influenced by geometry, temperature, and loading conditions. Due to the limited availability of irradiated materials, using small-scale samples is desirable. In this work, fracture toughness tests were performed on three compact tension samples (50 mm wide and 25 mm thick) made from Grade P91 steel, a material similar to EUROFER97, at 600°C. Crack length was monitored using Direct Current Potential Drop method, while surface strains were measured via Digital Image Correlation. The average <em>J<sub>IC</sub></em> value was found to be equal to 321 kPa·m, though significant plastic deformation around the crack tip was observed. This deformation, combined with the non-rectilinear crack propagation, led to questioning the predictions of the standards, with a final <em>J<sub>IC</sub></em> value of 800 kPa·m based on physical crack extension measurements. The influence of sample size was also explored, revealing that larger specimens are more likely to achieve plane strain conditions, while miniature ones tend to exhibit plane stress dominance at the crack tip, leading to lower toughness values.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 439-445"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenqi Liu , Zibiao Wang , Tao Shi , Jianrong Liu , Guian Qian
{"title":"Temperature and strain rate sensitivity characterization of a Ti65 alloy by machinal learning method","authors":"Wenqi Liu , Zibiao Wang , Tao Shi , Jianrong Liu , Guian Qian","doi":"10.1016/j.prostr.2025.06.082","DOIUrl":"10.1016/j.prostr.2025.06.082","url":null,"abstract":"<div><div>This study proposes a straightforward and efficient investigation method to reveal the complex temperature and strain rate sensitivity of Ti alloys. A concise experimental program was designed for a Ti65 alloy to cover the temperature range of 25~650 °C and the strain rates from 10<sup>-5</sup> to 10<sup>-2</sup> s<sup>-1</sup> with the smooth round bar samples. Tensile properties including the elastic modulus, yield strength, tensile strength, and fracture elongation were analyzed. It is indicated that the Ti65 alloy performed the dynamic strain aging effect in a certain temperature–strain rate interval and creep behavior at high temperatures, resulting in the non-monotonous and non-linear temperature and strain rate effects on the tensile properties of Ti65. The classical theory, i.e. the Johnson–Cook model, and the machine learning technique, i.e. support vector regression (SVR) algorithm, were adopted to predict the tensile properties of the investigated Ti65 at extensive temperature and strain rate ranges. It is demonstrated that the SVR algorithm is a suitable machine learning solution for the small amount of sample data with complicated non-linear dependence. With only 11 groups of experimental input data, the prediction performance of the SVR algorithm on strength is 7 times better than the Johnson–Cook model and the deviation between the predicted and measured properties is less than 3% for both strength and elongation prediction.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 458-464"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparing Direct Method and Backpropagation method in Determining GTN Parameters: A Quantitative Study","authors":"Chahboub Yassine , Szavai Szabolcs","doi":"10.1016/j.prostr.2025.06.059","DOIUrl":"10.1016/j.prostr.2025.06.059","url":null,"abstract":"<div><div>GTN model is among the best models that simulate crack growth at the microscopic level. Estimating crack propagation is vitally important to ensure an effective operation of different equipment and avoid breakdowns, especially in the field of nuclear energy.</div><div>However, the GTN parameters determination is a complicated process that requires much time and analysis.</div><div>Several studies have dealt with this problem and tried different methods to determine GTN parameters, some examples being the direct method, and the backpropagation method.</div><div>My main objective in this work was to do a quantitative comparison among the direct method and the backpropagation approach and to find out the best and the method which is fully optimized for the GTN parameters.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"68 ","pages":"Pages 310-317"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multiphysics Modeling of NiTi Shape Memory Alloy Fabricated by Laser Powder Bed Fusion Using Computational Fluid Dynamics","authors":"Mohammadjavad Abdollahzadeh, Mohammadreza Nematollahi, Hossein Abedi, Fatemeh Kordizadeh, Shiva Mohajerani, Mohammad Elahinia","doi":"10.1016/j.prostr.2025.07.002","DOIUrl":"10.1016/j.prostr.2025.07.002","url":null,"abstract":"<div><div>Laser Powder Bed Fusion (LPBF) is a transformative additive manufacturing technique capable of producing high-performance components with intricate geometries. This study focuses on the LPBF of NiTi alloys. Material properties were predicted using Thermo-Calc (V-2022a), employing the ‘Scheil Solidification simulation’ and ‘property model calculation’ to account for time-dependent thermal and physical behavior during processing. These properties were integrated into a Computational Fluid Dynamics (CFD) model to analyze the morphology of the melt pool, as well as the dynamic fluid flow, heat transfer, and key phenomena such as Marangoni convection, recoil pressure, and defect formation under realistic conditions.</div><div>The powder bed was simulated using the Discrete Element Method (DEM) to replicate the random particle distribution typical of real-world LPBF processes. The results, validated against experimental data with an error of ~15%, revealed relationships between energy density, melt pool morphology, and defect formation. Key phenomena such as Marangoni convection, recoil pressure, and Rayleigh instability were identified as primary factors influencing melt pool behavior. The temporal evolution of the melt pool highlighted the role of thermal gradients and laser penetration depth in achieving uniform fusion.</div><div>This study provides insights into LPBF melt pool physics and process optimization, offering a framework for the reliable fabrication of high-quality NiTi components. These findings have significant implications for advancing applications in various industries.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"69 ","pages":"Pages 2-19"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144587885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Surki Aliabad , S. Sadeghpour , P. Karjalainen , J. Kömi , H. Singh , V. Javaheri
{"title":"Carbon Redistribution in a Martensitic Medium Mn Steel During Heating to Intercritical Region: An In-Situ Synchrotron XRD Study","authors":"R. Surki Aliabad , S. Sadeghpour , P. Karjalainen , J. Kömi , H. Singh , V. Javaheri","doi":"10.1016/j.prostr.2025.07.010","DOIUrl":"10.1016/j.prostr.2025.07.010","url":null,"abstract":"<div><div>This study investigates the microstructural evolution and carbon redistribution during the heating stage prior to intercritical annealing treatment (IAT) in a medium manganese steel (MMnS) with the nominal composition of Fe-0.40C-6Mn-2Al-1Si-0.05Nb (wt.%). The material was characterized using high-energy X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The initial microstructure primarily consisted of tempered martensite containing nano-sized plate-like η carbides and 7 vol.% retained austenite (RA) with thicknesses of 10–20 nm and 300 nm in average, respectively. During heating, carbon partitioning caused an increase in carbon content within the RA up to 530 °C, rising from 0.4 wt.% to 1 wt.%. η-carbides initially coarsened and subsequently transformed into cementite with an average diameter of ~20 nm. Above 530 °C, RA began to decompose, resulting in the formation of a pearlite-type microstructure. Concurrently, the carbon content in the remaining RA decreased, facilitating further growth of cementite formed in the earlier stages.</div><div>The microstructure at the onset of IAT at 640 °C consisted of tempered martensite with nano-sized spherical cementite, 9 vol.% RA with >1 wt.% carbon and a small fraction of pearlite-type decomposed RA. The study highlights the complex interplay between carbon redistribution, carbide formation, and RA stability during the heating stage of MMnS and emphasizes the importance of accurately characterizing the initial microstructure to tailor the properties of these advanced high-strength steels.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"69 ","pages":"Pages 69-75"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144587893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Victor Komarov , Roman Karelin , Vladimir Cherkasov , Ivan Postnikov , Grzegorz Korpala , Irina Khmelevskaya , Vladimir Yusupov , Rudolf Kawalla , Ulrich Prahl , Sergey Prokoshkin
{"title":"Deformation Behavior of NiTi Shape Memory Alloy Subjected to Severe Torsion Deformation","authors":"Victor Komarov , Roman Karelin , Vladimir Cherkasov , Ivan Postnikov , Grzegorz Korpala , Irina Khmelevskaya , Vladimir Yusupov , Rudolf Kawalla , Ulrich Prahl , Sergey Prokoshkin","doi":"10.1016/j.prostr.2025.07.011","DOIUrl":"10.1016/j.prostr.2025.07.011","url":null,"abstract":"<div><div>In the present work, the possibility of application severe torsion deformation (STD) to a bulk near-equiatomic NiTi shape memory alloy in order to accumulate high strain was studied. STD was performed using the multidirectional test system “BÄHR MDS-830” in a temperature range of 300-600 °C (the dynamic polygonization range) in 10 turns with accumulated true strain of <em>e</em> = 3. The results obtained show the prospects of application STD to bulk NiTi samples in terms of large strains accumulation. The STD at 350-600 °C leads to the formation of steady state flow stress stage. The polygonized dislocation substructure can be formed in this temperature range at <em>e</em> = 0.6 to 3. The obtained flow curves can be used for mathematical modeling and optimization of deformation processes of NiTi alloys.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"69 ","pages":"Pages 76-79"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144587894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Flores-Vivián , M. López-Morales , K. Sobolev , L. Vergara-Álvarez , G.J. Fajardo-San Miguel , B.T. Terán-Torres , R. Hermosillo-Mendoza , G. Ortiz-Rabell , D. Luiza Da Silva , S. Castro-Angulo
{"title":"Nanozeolite Synthesis and Application in a Metakaolin-Based Geopolymer","authors":"I. Flores-Vivián , M. López-Morales , K. Sobolev , L. Vergara-Álvarez , G.J. Fajardo-San Miguel , B.T. Terán-Torres , R. Hermosillo-Mendoza , G. Ortiz-Rabell , D. Luiza Da Silva , S. Castro-Angulo","doi":"10.1016/j.prostr.2025.06.010","DOIUrl":"10.1016/j.prostr.2025.06.010","url":null,"abstract":"<div><div>Alkali-activated cementitious cement such as geopolymers represent an alternative that allows to reduce the carbon footprint in the construction industry due to the CO<sub>2</sub> emissions to the atmosphere that occur during the manufacture of portland cement (CP). During the synthesis of geopolymers, zeolites (mainly faujasite) are formed, which contribute to the improvement of strength and durability. In this work, faujasite type NaY was synthesized from Sodium Hydroxide (NaOH), soluble Sodium Silicate (Na<sub>2</sub>SiO<sub>3</sub>) and Sodium Aluminate (NaAlO<sub>2</sub>). The nanozeolite was added to a metakaolin-based geopolymer, activated with an alkaline solution composed of NaOH and Na<sub>2</sub>SiO<sub>3</sub>. The geopolymer was prepared by varying the molarity of the NaOH in the alkaline activating solution (AAS). Two types of zeolites were used: natural clinoptilolite-type faujasite and synthesized NaY-type faujasite. The hydration process was analyzed using Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). According the results, increasing the molarity of the NaOH of the alkaline activator (AA) promotes the dissolution of bonds, favoring the formation of aluminum-rich species and a higher degree of polymerization.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"67 ","pages":"Pages 80-89"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}