Keynote lectures

Keynote lectures

Milos Djukic, Professor

Faculty of Mechanical Engineering, University of Belgrade, Serbia

Biography:

Milos B. Djukic is a full professor at the University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia. His research interests include hydrogen embrittlement, hydrogen-materials interactions, corrosion and materials science, materials degradation, and the mechanical behavior of materials. He is the head of the Hydrogen-Materials Interaction Laboratory at the University of Belgrade.

Prof. Djukic is a member of the team for preparation of the Hydrogen Strategy of the Republic of Serbia and an Executive Committee Member of the European Structural Integrity Society (ESIS). He also serves as the chair of ESIS Technical Committee TC21 on Hydrogen Embrittlement and Transport. He is an assistant subject editor for the International Journal of Hydrogen Energy by Elsevier, and a member of the editorial board of eighteen international journals, including Metallurgical and Materials Transactions A and Engineering Failure Analysis.

With over 25 years of teaching and research experience, Dr. Djukic has published 5 books, 10 book chapters, 1 patent, 3 technical solutions, more than 100 peer-reviewed scientific papers in international journals, and 120 conference articles. He has contributed to more than 200 industrial studies, reviews, reports, and expertise. Prof. Djukic scientific research focuses on the fundamental understanding of hydrogen embrittlement mechanisms in metallic materials and hydrogen-materials interactions. He proposed the novel hydrogen embrittlement model in metallic materials based on the synergy of mechanisms. This so-called HELP+HEDE model has been widely accepted and is highly cited with more than 700 citations.

He is included in the 2023 list of the 2% most cited researchers worldwide, published by Stanford University and curated by Elsevier using Scopus data. According to Scopus, he has 1510 citations with an h-index of 15 and has five papers related to hydrogen embrittlement topic cited more than 100 times. According to Google Scholar, he has 2908 citations. He was a keynote/invited speaker at 20 international conferences. He was a mentor, opponent, and member of defense or pre-examination committees for fourteen Ph.D. theses, related mostly to hydrogen embrittlement topics in Belgium, Austria, Finland, France, Israel, Brazil, Australia, and Serbia. Dr. Djukic is an external peer reviewer for scientific projects of five European scientific government agencies in Belgium, Switzerland, Poland, Norway, the Netherlands, and South Africa. He is also a research projects peer reviewer for the European Research Council (ERC).

Title: Hydrogen embrittlement mechanisms synergy in metallic materials: HELP + HEDE model

Abstract: The HELP+HEDE model is a comprehensive concept that explains the coexistence of hydrogen embrittlement (HE) mechanisms in metallic materials [1,2]. This model involves the interplay and competence between two groups of HE mechanisms: HELP and/or other plasticity-mediated HE mechanisms, and HEDE mechanism [1-3]. The confirmed competition and transition in dominance between plasticity-mediated HE mechanisms (HELP, and others), and HEDE, depending on the global/local hydrogen concentration and distribution, microstructural characteristics, and stress state, are of utmost importance to achieve a unified model for HE. This paper presents new insights about the HELP+HEDE model, validated through experiments [3] and modeling studies [4], i.e., the "Local HEDE micro-incidents" concept, "HEDE-prone H traps" concept, and conditions for particular HE mechanism dominance, highlighting its significance in the fundamental understanding of HE phenomena in metallic materials. 


References

[1] M.B. Djukic, G.M. Bakic, V. Sijacki Zeravcic, A. Sedmak, B. Rajicic. The synergistic action and interplay of hydrogen embrittlement mechanisms in steels and iron: Localized plasticity and decohesion. Eng. Fract. Mech. 216, (2019), 106528. 

[2] M. Wasim, M.B. Djukic, T.D. Ngo. Influence of hydrogen-enhanced plasticity and decohesion mechanisms of hydrogen embrittlement on the fracture resistance of steel. Eng. Fail. Anal. 123, (2021), 105312. 

[3] Q. Zhao, H. Luo, M.B. Djukic, Z. Pan, H. Cheng, R.K. Islamgaliev. Hydrogen-induced crack behavior of a precipitation-strengthened Ni50Cr20Co15Al10V5 high entropy alloy. Corros. Sci. 241, (2024), 112562.

[4] H.W. Lee, M.B. Djukic, C. Basaran. Modeling fatigue life and hydrogen embrittlement of bcc steel with unified mechanics theory. Int. J. Hydrogen Energ. 48(54), (2023), 20773-20803.

Filippo Berto, Professor

Sapienza University of Rome, Italy

Biography:

Since fall 2022, Filippo Berto is Professor of mechanics of Materials at Sapienza University of Rome. Previously he has been international chair in fracture mechanics, fatigue, and structural integrity at the Norwegian University of Science and Technology of Trondheim, Norway, since beginning of 2016. He was professor of machine design at the University of Padua, Italy, between 2006 and 2015. He is chairman of the technical committee ESIS TC15 on Structural Integrity of additive manufactured components of European Structural Integrity Society. In 2020 he has been one of the founders of TC18 of ESIS dedicated to the structural integrity of welded structures. 

Title: Fatigue assessment of large structures: open issues and possible solutions 

Abstract: Fatigue design of large structures is still an open problem which affects designers all over the world. The aim of the talk is to give a brief overview of open issues and possible design solutions that can help the designers to face these challenges. Advanced applications of local approaches will be discussed in this regard with particular attention to energy based approaches. 

Dorin Radu, Professor

Faculty of Civil Engineering, Brașov, Romania

Biography:

Dorin Radu is Associate Professor and Vice Dean of the Faculty of Civil Engineering, Transilvania University of Brașov. He holds lectures in Static and Stability of the Structures, Theory of Elasticity and Plasticity and Building Information Modelling. His research interest is in structural integrity, assessment and optimization of existing structural elements, new materials for sustainable constructions, neural networks applied in civil engineering. He is the author of several books, conference papers and large number of articles published in high ranked journals.

Title: Structural integrity assessment – part of a sustainable development 

Abstract: The in-service safety assessment of existing steel structures is a complex problem which requires interdisciplinary approaches – from civil engineering application using Eurocodes or European recommendation for fatigue life estimation, up to an in-depth assessment by means of fracture mechanics. The scope of the presentation is to describe possible solutions for assessment of existing steel structures using Engineering Critical Assessment approach and applying to several study cases.

Francesco Iacoviello, Professor

University of Cassino and Southern Lazio, Department of Civil and Mechanical Engineering, Italy

Biography:

Francesco Iacoviello is full professor of Metallurgy at the Faculty of Engineering of the University of Cassino and Southern Lazio. He was President of the Italian Group of Fracture - IGF (2009-2021), President of the European Structural integrity Society – ESIS (2018-2022), Vice-President of the International Congress on Fracture (2017- 2023).

He is Director of the International Congress on Fracture, Editor in Chief of Fracture and Structural Integrity and of Procedia Structural Integrity and Deputy Rector for Services and Infrastructures at the University of Cassino and Southern Lazio. His main research fields concern the analysis of fatigue crack propagation resistance and damaging micromechanisms of stainless steels, ductile cast irons, Al and Ti alloys, shape memory alloys, additively manufactured alloys and Zn coated steels, the investigation of stainless steels hydrogen embrittlement mechanisms and the analysis of stainless steels localized corrosion micromechanisms. 

Title: Ductile Cast Irons: porous steels or natural composites? 

Abstract: In 1943 and in 1948, the addition of magnesium and of cerium, respectively, allowed to obtain graphite elements embedded in ferritic-pearlitic matrix with mechanical properties that were analogous to those offered by malleable cast iron, but with a reduced production cost. In the last decades, the interest on ductile cast irons (DCIs) strongly increased and many different grades were optimized in order to offer a wider range of properties depending both on the chemical composition and on the heat treatment. The increasing industrial interest on DCIs offered a strong motivation to improve the knowledge of the damaging mechanisms of these grades, considering both their peculiar microstructure (a sort of “natural” composite, with graphite nodules embedded in a metallic matrix) and the different loading conditions (static, quasi static, cyclic etc.). A crucial point in the analysis of the damaging micromechanisms in DCIs concerns the role played by the graphite nodules. The aim of this presentation is to offer an overview of the different proposed damaging mechanisms and the different roles that can be assigned to the graphite nodules. 

José A. F. O. Correia, Professor

Faculty of Engineering of the University of Porto, Portugal 

Biography:

José A.F.O. Correia was born in 1984 in Peso da Régua, Portugal, and is currently a Professor and a Researcher at the CONSTRUCT institute, Faculty Engineering, University of Porto (FEUP, Portugal). Since March 2018, He is a Guest Professor at the Delft University of Technology (Netherlands). Also, He was an Invited Professor at the University of Porto (2018-2019) and at the University of Coimbra (2016/09-2021/08), and He was an Associate Professor by invitation at UTAD (2022/03-2023/02).

In 2007, José A.F.O. Correia obtained a Graduation in Civil Engineering (5 academic years) from UTAD. In 2009, He obtained the MSc. in Civil Engineering (Structural Mechanics) from UTAD. He has a Specialization in Steel and Composite Construction from the University of Coimbra (2010). In 2015, He got a Ph.D. Degree in Civil Engineering from the University of Porto. In 2024, He obtained the Habilitation in Civil Engineering – Fatigue and Structural Integrity from the University of Porto.

Since 2019, Doctor José A.F.O. Correia is included in the world’s top 2% scientists list of the Stanford University ranking. José A.F.O. Correia is co-author of more than 234 journal papers in the most relevant scientific journals, 200 proceedings in conferences, 18 book chapters, and also co-author of 22 books (15 completed; 7 ongoing). The candidate also edited more than 21 issues of scientific journals as a Guest Editor. In the Scopus platform, He is (co)author of 339 documents in the most relevant scientific journals, has an h-index equal to 42 and 5668 citations.

Since 2015, He is editorial board member, editor-in-chief, and section editor of 26 scientific journals and book series – International Journal of Fatigue (Elsevier), Structures (Elsevier), Alexandria Engineering Journal (Elsevier), Heliyon (Elsevier), Forces in Mechanics (Elsevier), Philosophical Transactions A (The Royal Society), Smart Infrastructure and Construction (ICE), International Journal of Structural Integrity (Emerald), Modelling journal (MDPI), Structural Integrity (Springer), Structural Damage, Fatigue and Fracture (Taylors & Francis), Journal Offshore Mechanics and Arctic Engineering (ASME), Journal of Structural Design and Construction Practice (ASCE), Ships and Offshore Structures (Taylor & Francis), etc.

He was/is a supervisor of doctoral and master’s students in the areas of Civil and Mechanical Engineering – 24 Ph.D. (9 completed and 15 ongoing) and 51 MSc. (47 completed and 4 ongoing).

He was/is the (co)coordinator at FEUP of 7 R&D projects (e.g. FADEST, FiberBridge, SOS-WindEnergy, Hyperloop-Verne, PT-Chinese Project, NEXUS, SuRe3-OW-GH2) and consulting services (university extension) budgeted at more than 1000k€ and 190k€, respectively. In business activities, He was involved in approved investment projects budgeted more than 720k€.

José A.F.O. Correia received several distinctions and awards – by the Wrocław Univ. of Sci. of Tech. (Poland), Univ. of Elect. Sci. and Tech. of China (China) and Beihang Univ. (China), FEUP Scientific Recognition Award 2019, 2020, 2021, 2022 and 2023, Highly Cited Paper (Clarivate) – 2021 and 2022, Manson-Coffin IGF 2021 medal, Philo Mechanicus award 2023, IAAM Scientist Medal 2024.

Title: Probabilistic stress-life prediction at variable amplitude loading based on the non-linear accumulation 

Abstract: In 1924, Palmgren [1] suggested for the first time the concept of the linear damage rule (LDR). About two decades later (1945), Miner [2] proposed the first mathematical expression for the damage computation. Fatigue damage ( ) can be calculated in terms of the number of cycles applied at a given stress range ( ) divided by the corresponding number of cycles required to produce failure at the same stress range ( ). Miner’s model is proposed in the majority of design codes. The sequential loading effects not properly accounted using the Miner’s model. Therefore, the non-linear damage accumulation models are required when sequential effects are important. Due to deficiencies associated with LDR, Marco and Starkey [3] proposed the first non-linear load-dependent damage theory, in 1954. In 1960, the two-stage linear damage approach suggested by Langer and Grover [4] considered cycle ratios for two separate stages, in the fatigue damage process of constant amplitude stressing: 1) Damage due to crack initiation, ; and, 2) Damage due to crack propagation,  where α is a life fraction factor for the initiation stage. In 1966 and 1981, a double linear damage rule (DLDR) for treating cumulative fatigue damage was proposed by Manson & Halford [5]. Recently, Huffman & Beckman [6] proposed a non-linear damage accumulation fatigue model in which is modelled by calculating the damage of each cycle based on the state of damage when that cycle occurs, using the assumption that damage accumulation behaves like crack growth. The effect is that for any particular reversal to a tensile stress in a variable amplitude stress history, that stress reversal will cause more damage later in a history than it will at the beginning of the history. An important issue of fatigue damage accumulation theories is their development on a deterministic form, when it is well recognized the probabilistic nature of the fatigue lifetime. Some attempts have been presented in the literature concerning probabilistic fatigue approaches, but fundamentally they are based on linear damage summation approaches [7,6,8,10]. In this research work, a methodology based on the non-linear accumulation and probabilistic modelling for stress-life prediction at variable amplitude loading using fatigue data at constant amplitude loading. The probabilistic modelling used in the non-linear damage accumulation fatigue model is based on probabilistic S-N fields for constant amplitude fatigue data proposed by Castillo and Fernández-Canteli [11,12]. This proposed methodology is validated using experimental variable amplitude fatigue data for riveted joints made of puddle iron from the Fão Bridge under stress-controlled conditions [13,14]. This methodology can be generalized for the local fatigue damage models and various probabilistic approaches.


References

[1] Palmgren, A.G., Die Lebensdauer von Kugellagern (Life Length of Roller Bearings or Durability of Ball Bearings). Zeitschrift des Vereines Deutscher Ingenieure (ZVDI), 1924, 14, 339-341.

[2] Miner, M.A., Cumulative damage in fatigue, Journal of Applied Mechanics. 1945, 67, A 159-A 164.

[3] Marco, S.M. and Starkey, W.L., A concept of fatigue damage. Transactions of the ASME, 1954, 76, 627-632.

[4] Grover, H.J., An observation concerning the cycle ratio in cumulative damage. In Symposium of Fatigue of Aircrafts Structures, ASTM STP 274. American Society for Testing and Materials, Philadelphia. PA, 1960, 120-124.

[5] Manson, S.S. and Halford, G.R., Practical implementation of the double linear damage rule and damage curve approach for treating cumulative fatigue damage, International Journal of Fracture, vol. 17, no. 2, 1981, 169-192.

[6] Huffman, P.J. and Beckman, S.P., A non-linear damage accumulation fatigue model for predicting strain life at variable amplitude loadings based on constant amplitude fatigue data, International Journal of Fatigue, vol. 48, 2013, 165–169.

[7] Pinto, H., De Jesus, A.M.P., Fernández-Canteli, A., Castillo, E., Pereira, H.F.S.G. Analysis of Constant and Variable Amplitude Strain-Life Data Using a Novel Probabilistic Weibull Regression Model. Journal of Pressure Vessels Technology, 132(6), 2010, 061401.

[8] Fernández-Canteli, A.,  Blasón, S.,  Correia, J.A.F.O., De Jesus, A.M.P., A probabilistic interpretation of the miner number for fatigue life prediction, Frattura ed Integrita Strutturale, vol. 30, 2014, 327-339.

[9] Correia, J.A.F.O., De Jesus, A.M.P., Fernández-Canteli, A., Calçada, R.A.B., Fatigue Damage Assessment of a Riveted Connection Made of Puddle Iron from the Fão Bridge using the Modified Probabilistic Interpretation Technique,  Procedia Engineering, vol. 114, 2015, 760-767.

[10] Correia, J.A.F.O., Balsón, S., De Jesus, A.M.P., Fernandez-Canteli, A., Calçada, R.A.B., A probabilistic analysis of Miner's law for different loading conditions, Structural Engineering and Mechanics, vol. 60, issue 1,  2016, 71-90.

[11] Castillo, E., Fernández-Canteli, A., A Unified Statistical Methodology for Modeling Fatigue Damage. Springer (2009).

[12] Correia, J.A.F.O.C., Apetre, N., Arcari, A., De Jesus, A.M.P., Muñiz-Calvente, M., Calçada, R., Berto, F., Fernández-Canteli, A., Generalized probabilistic model allowing for complex fatigue damage variables, International Journal of Fatigue, vol. 100, Part 1, 2017, 187-194.

[13] de Jesus, A.M.P., Silva, A.L.L., Correia, J.A.F.O., Fatigue of riveted and bolted joints made of puddle iron – A numerical approach, Journal of Constructional Steel Research, vol. 102, 2014, 164-177.[14] de Jesus, A.M.P., Silva, A.L.L., Correia, J.A.F.O., Fatigue of riveted and bolted joints made of puddle iron - An experimental approach, Journal of Constructional Steel Research, vol. 104, 2015, 81-90. 

Dragan Bojovic, Dr. 

IMS Institute, Belgrade, Serbia

Biography:

Title: to be announced

Abstract:

Bojan Medjo, Professor

Faculty of Technology and Metallurgy, University of Belgrade, Serbia  

Biography:

Bojan Medjo is currently Associate Professor at the University of Belgrade, Faculty of Technology and Metallurgy, Department for General Technical Sciences. His research activities are in the fields of mechanics of materials, fracture mechanics, local approach to fracture and integrity assessment of inhomogeneous structures, including the application of the finite element method in these fields. He is author or co-author of two course books and numerous papers published in international and national scientific journals and conference proceedings, as well as reviewer for several international scientific journals. 

Title: Non-standard tensile and bending ring specimens for fracture examination of pipeline materials

Abstract: In the previous period, a significant number of studies worldwide have dealt with determination of fracture resistance of the pipeline materials. The main focus is on the thin-walled pipes, because it is typically difficult, or impossible, to fabricate standard fracture mechanics specimens such as Single Edge Notch Bending (SENB) or Compact Tension (CT). Therefore, two non-standard specimen geometries developed in the previous period will be presented and discussed. Both of them are ring-shaped, and the difference is in the loading type: tension in the case of Pipe Ring Notch Tension (PRNT) specimens or bending in the case of Pipe Ring Notch Bending (PRNB) specimens. 

Grzegorz Lesiuk, Professor

Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Poland

Biography:

Member of the Committee on Mechanics and Civil Engineering of the Polish Academy of Sciences branch Wrocław, President of the Polish Group of Crack Mechanics (PGMP), President of the Wroclaw Branch of PTMTS (Polish Society for Theoretical and Applied Mechanics), Grzegorz Lesiuk, Ph.D., DSc.  professor of the WUST (Wroclaw University of Science and Technology), has been employed at the Wrocław University of Technology (Faculty of Mechanical Engineering) since 2009. He received his doctoral degree in technical sciences in 2013, and received his habilitation in 2020 at the Faculty of Mechanical Engineering of Wrocław University of Technology. His scientific activities are in the field of mechanics, fracture mechanics and fatigue of materials and structures, as well as new materials and modeling of their durability under cyclic and static loads. In this field, he has more than 120 scientific papers published in renowned national and international scientific and technical journals, as well as more than 70 conference papers and 1 patent. He is a member of the Polish Society of Theoretical and Applied Mechanics and ESIS (European Structural Integrity Society). As part of his teaching activities, he gives lectures and exercises in courses on mechanics, strength of materials, fracture mechanics for students of Wroclaw University of Technology. He is co-author of an academic mechanics coursebook and co-author of a monograph (Springer) on the problems of degradation of materials and structures. For years, he has cooperated extensively with foreign centers in Europe (mainly Porto, Coimbra-Portugal, Oviedo-Spain, Milan, Cassino, Bologna-Italy, Brno, Prague-Czech Republic, Lviv, Kiev-Ukraine, Chemintz, Kaiserslautern-Germany, Trondheim-Norway, Nove Mesto-Slovenia) and abroad (Brazil-São Paulo, Minas Gerais, China-Chengdu, USA-Michigan, Canada-Waterloo, Zabol-Iran, Boumerdes-Algeria). He is a co-organizer of many scientific events of international as well as national scope, i.e. XXICMFM (International Colloquium Mechanical Fatigue of Metals), XVIII KKMP (National Conference on Fracture Mechanics), 1st VCMF (Virtual Conference on Fatigue of Metals), 9th Symposium - Layered Structures, and the creator of a new initiative under ERASMUS BIP courses for summer and winter schools of fracture mechanics and fatigue of materials. He has been repeatedly awarded for his scientific activities: Admission as a member of the Academy of Young Scientists and Artists operating at the Mayor of the City of Wroclaw - nomination received from the Mayor of the City of Wroclaw (2018), Award of the Rector of Wroclaw University of Technology (2018, 2020), International ESIS Award - TC12 (Merit Award) 2019 and 2 international TOP 1% Reviewers (Publons&Web of Science) awards - 2019, Lierati Award (2019) - Emerald Journals Group, 2023 - ESIS Award of Merit - Robert Moskovic Award (Serbia, IV, 2023), - Faculty of Engineering Porto medal  University of Porto - 2023. In addition, in his career he has managed numerous projects of national as well as international scope funded by NCBiR, NCN, NAWA.

Title: Strain Energy density parameters as a crack driving force in fatigue crack growth rate analysis

Abstract: The main problem with the description of FCGR (Fatigue Crack Growth Rate) is a strong dependency on stress ratio R. It is clear that the mean stress effect is reflected in various semi-empirical equations. However, in some energy-based models, observing different descriptions of FCGR phenomena using strain energy density parameters like dissipated energy is possible. During the lecture, it will be performed a simplified review of energy models and my research results of FCGR description in several kinds of steels under mode I and mixed mode concerning different stress ratios. As it can be concluded, the main advantage of the energy approach is the R-ratio invariant description of FCGR. 

Raheem Al-Sabur, Associate Professor

Faculty of Engineering of the University of Basrah, Iraq

Biography:

Dr. Raheem Al-Sabur is an Associate Professor in the Department of Mechanical Engineering at the University of Basrah’s Engineering College. A faculty member since 2002, he has dedicated over two decades to advancing research and education in structural integrity, welding technologies, and mechanical systems. Dr. Al-Sabur earned his Ph.D. in Virtual Welding Simulation from the University of Basrah in 2014, with his research focusing on virtual models for welding process optimization. His expertise extends across several areas of mechanical engineering, including residual stress analysis, fatigue testing, and structural performance assessments, particularly in welded joints and composite materials.

An active and prolific researcher, Dr. Al-Sabur has authored over 45 peer-reviewed publications in high-impact engineering journals and has served as a reviewer for more than 140 manuscripts in prestigious journals, such as Engineering Failure Analysis, Materials Science Forum, and Journal of Process Mechanical Engineering. Dr. Al-Sabur is a prominent member of professional organizations, including the American Welding Society (AWS), the German Welding Society (DVS), and the Iraqi Engineers Association, which have been instrumental in fostering his ongoing work in welding technologies. He is frequently invited to deliver keynote presentations at international conferences, where he shares insights from his research on structural integrity, non-destructive testing, and welding innovations.

Title: Mechanical integrity and friction stir spot welding performance of aluminum and magnesium sheets for next-generation aerospace and automotive applications

Abstract: Welding lightweight materials such as aluminum and magnesium ensures optimal structural integrity in welding joints; this is essential for applications requiring high strength and durability, as improper welding conditions can lead to defects and reduced load-bearing capacity. Friction stir spot welding (FSSW) is an effective method for joining similar and dissimilar lightweight metals, even with differences in their densities and melting points. The structural integrity of friction stir spot welding joints depends on factors such as material properties, process parameters, and tool design, which affect the mechanical performance of the joint and its fatigue resistance. This study investigated the mechanical properties of aluminum alloy EN AW 2024-T4 and magnesium alloy AZ31B, as well as their joint performance with FSSW. The results obtained were examined by performing tensile and tensile-shear tests. The experimental results demonstrate that lightweight design engineering applications can use both the mechanical properties of the base material and the combined performance of the FSSW-joined Al-Mg thin sheets, even though their densities differ by up to 25%. When the FSSW joints were put through tensile-shear tests, the results showed that they could handle 1500 N for AZ31B but 3850 N for EN AW 2024-T4. The ultimate tensile stress was 240 MPa and 425, respectively.