Early Stage Researchers (ESRs)
The Newfrac Computational Platform» collects the common computational tools and knowledge basis for the network. You will find here the progress of the work of the network and the related codes we develop to solve fracture mechanics problems.
Karthik Ambikakumari Sanalkumar
“As a crack to crack the cracks”: a dedicated researcher in fracture mechanics, striving to unravel the mysteries of crack initiation and propagation and provide solutions for brittle materials.
ESR01: Total energy minimization with stress conditions for mixed mode fracture in anisotropic heterogeneous materials and structures. See details»
Karthik is from Kerala, a state in southern India. He is an enthusiastic researcher with over two years of experience in numerical methods and a motivated engineering university postgraduate specialising in computer science and continuum mechanics.
He graduated with rank from Kerala University in 2015 with a BTech in Mechanical Engineering. After obtaining the MSc. in Computer Science in Engineering at TU Braunschweig, Germany, in May 2019, he worked as a research assistant at TU Berlin in cooperation with Fraunhofer IZM for almost a year.
He is currently a NewFrac ITN Early Phase Research Fellow (MSCA), working with Professor Vladislav Mantic (Sevilla) and Professor Marco Paggi (Italy), with his research interests focused on fracture mechanics.
Lucca, Italy // Duration: 5 months (March 2022 - August 2022)
- Object: Development of modelling strategies and their computational implementation. The code's outcomes will be contrasted against other numerical techniques, including Cohesive Zone Models (CZM) and Phase Field (PF) methods, in addition to experimental data drawn from various literature sources. This comparative examination will gauge the code's precision and dependability in representing diverse fracture phenomena.
- Personal Experience: During my research period at IMT School for Advanced Studies in Lucca, Italy, from March to August 2022, I had the opportunity to immerse myself in a vibrant research atmosphere. Collaborating with dedicated colleagues and accessing well-equipped laboratories greatly enriched my experience as I worked on developing modelling strategies and implementing them computationally.
Robert Bosch, Germany // Duration: 6 months (March 2023 - May 2023 and October 2023)
- Object: to validate the developed computational tools that solve industrial fracture problems in SFRP composites.
- Personal Experience: Additionally, during my time as ESR01 at Robert Bosch in Germany, from March to May 2023 and again in October 2023, I gained valuable insights into real-world industrial fracture problems in SFRP composites. My interactions with experts in the field and the hands-on experience in applying the developed computational tools were instrumental in broadening my research perspective and skills.
- Marie Skłodowska-Curie Actions (MSCA) Satellite Event, held in Katowice, Poland, 10th and 11th June, 2024
- EuroScience Open Forum 2024, held in Katowice, Poland, from 12th to 15th June, 2024
- NewFrac Conference – New Computational Strategies for Fracture, held in Porto, Portugal, from 07th to 10th May, 2024
- EUROMECH COLLOQUIUM 635 - Finite Fracture Mechanics held in Lyon, France, from 12th to 14th September, 2023
- CFRAC 2023 - Seventh International Conference on Computational Modelling of Fracture and Failure of Materials and Structures, held in Prague, Czech Republic, from 21st to 23rd June, 2023.
- ICF15 - 15th International Conference on Fracture, held in Atlanta, Georgia, USA, from 9th to 19th June, 2023
- NewFrac & TC16 Joint Workshop – “Reaching Out”, held in Torino, Italy, from 17th to 20th January, 2023
- FDM 2022 - 20th International Conference on Fracture and Damage Mechanics, held in Malaga, Spain, from 5th to 7th September, 2022
- ECF23 - European Conference and Summer School on Fracture 2022 held in Funchal, Madeira, Portugal, from 25th June 2022 to 2nd July 2022
- NewFrac Workshop 2 – “Expanding Horizons”, held in Lucca, Italy, from 09th to 12th May, 2022
- NewFrac Workshop 1 – “New Strategies in Computational Fracture Mechanics”, held in Seville, Spain, from 1st to 8th October, 2021
Dissemination
Moreover, I have taken part in the European Researchers’ Night during 3 years, an amazing opportunity to bring science closer to people who are not involved in the field.
This PhD research project, assigned to Early-Stage Researcher (ESR) 1, aims to develop and implement a computational code based on the Coupled Criterion of Finite Fracture Mechanics (CCFFM) with the new formulation known as the Principle of Minimum Total Energy subjected to a Stress Condition (PMTE-SC). The code will be specifically designed to accurately predict the initiation and propagation of cracks in brittle materials.
The primary task involves the development of a computational code that incorporates the PMTE-SC algorithm to ensure the satisfaction of stress and energy conditions during crack advancement. The code will utilise a load-stepping algorithm to minimise the total energy change associated with crack growth. Cracks will be modelled as topological discontinuities within the finite element mesh, explicitly introduced during the domain discretisation and aligned with element edges.
A series of benchmark problems will be investigated to validate the developed code. These problems include mixed-mode crack propagation, scenarios involving multiple cracks, interface problems, and anisotropic materials. The results obtained from the code will be compared with other numerical procedures, such as Cohesive Zone Models (CZM) and Phase Field (PF) methods, as well as experimental results from various literature sources. This comparative analysis will assess the accuracy and reliability of the code in capturing different fracture phenomena.
This research project aims to advance the understanding and prediction of crack behaviour in brittle materials. Addressing various crack scenarios and considering factors such as mixed mode loading, multiple cracks, interfaces, and anisotropy will contribute to the comprehensive analysis of fracture mechanics. The resulting code will be a valuable tool for researchers and engineers, aiding the study and design of structures and materials susceptible to crack propagation.
In my Ph.D. research project, I'm developing a computational code that predicts the initiation and growth of cracks in brittle materials. I know that might sound a bit technical, but here's the gist: Imagine you have a glass or ceramic object, and you want to know how cracks might form and spread in it. That's what I'm studying.
The main goal of my research is to create a computer program that can accurately predict how these cracks will behave. We're using a unique algorithm called the Principle of Minimum Total Energy subjected to a Stress Condition, which is like a set of rules for how the cracks should grow. The computer program will be designed to make sure these rules are followed. To check if our program works correctly, we will test it in different situations, like when there are cracks in different directions or multiple cracks close to each other. We'll compare the results we get from our program with what other methods and experiments tell us. This will help us see if our program is good at understanding and predicting how cracks work.
We're doing all this to improve our understanding of how cracks form in things like glass, ceramics, and other brittle materials. This knowledge can be essential for engineers and researchers who design structures and materials that might crack over time. So, while it may seem a bit complicated, the end goal is to make things safer and better in the real world.
Expected Date: Before April 2025
My research contributes to several key EU policies. Firstly, it aligns with the EU industrial policy by aiming to enhance the competitiveness of EU industries. Through the development of a computational code that accurately predicts crack behaviour in brittle materials, my investigation supports the EU's goal of fostering innovation and growth within the industrial sector. This is particularly relevant as the EU seeks to lead in the transitions towards climate neutrality and digital leadership, where understanding and mitigating material weaknesses are crucial. Additionally, my investigation has relevance within Horizon Europe, the EU's framework program for research and innovation. By developing solutions to address policy priorities related to the green and digital transitions, my research supports the overarching aim of strengthening the EU's scientific and technological basis. It also contributes to tackling global challenges such as climate change and pollution, aligning with Horizon Europe's mission to address critical areas of concern.
In summary, my research contributes to EU policies by advancing knowledge in materials science and fracture mechanics, which in turn aids in the pursuit of industrial competitiveness, a unified research area, and innovation to address pressing societal and environmental challenges.
Simone Sangaletti
“Il più grande nemico della conoscenza non è l’ignoranza, ma l’illusione della conoscenza."
ESR02: Toughening composites by micro and meso structural optimization. See details»
Hello, my name is Simone, I am from Milan. I studied the Bachelor of Aerospace Engineering and then the Master in aeronautical engineering. I am now finishing my PhD at Universidad de Sevilla and I’m ESR02 in the NewFrac network.
ETH Zurich // Duration: 6 months (March 2022 – September 2022)
At ETH I focused the attention on the application of phase field modelling at the microscale for PEEK composite materials. The work has been carried out in collaboration with two departments: the Computational Mechanics group of Laura De Lorenzis and the CMAS lab of Paolo Ermanni. The work has been presented to the international conference ICCM2023 in Belfast. During the stay I had the occasion to meet all the guys from ETH and in particular Francesco (ESR10) and Camilla (ESR05) and to share with them not only theorems but also beers and parties!
Bottero // Duration 4 months (June 2023 – September 2023)
During this industrial secondment I have applied all the developments I have made during my PhD thesis. The stay was focused on the application of phase field modelling to study the fracture of bottles under vertical and pressure loading, given the actual geometry of the bottle including defects, obtained from tomographic techniques.
- COMPOSITES 2023 - 9th ECCOMAS Thematic Conference on the Mechanical Response of Composites, held in Trapani, Italy, from 12th to 14th September, 2023
- ICCM23 – International Conference on Composites Materials, held in Belfast, UK, from 30th July to 04th August, 2023
- CFRAC 2023 - Seventh International Conference on Computational Modelling of Fracture and Failure of Materials and Structures, held in Prague, Czech Republic, from 21st to 23rd June, 2023.
- NewFrac & TC16 Joint Workshop – “Reaching Out”, held in Torino, Italy, from 17th to 20th January, 2023
- ECF23, European Conference and Summer School on Fracture 2022 held in Funchal, Madeira, Portugal, from 25th June 2022 to 2nd July 2022
- NewFrac Workshop 2 – “Expanding Horizons”, held in Lucca, Italy, from 09th to 12th May, 2022
- NewFrac Workshop 1 – “New Strategies in Computational Fracture Mechanics”, held in Seville, Spain, from 1st to 8th October, 2021
Dissemination
Being part of the Universidad de Sevilla, I organized and took part in the European Researchers Night for two years. It was an amazing experience!
- “Fracture tailoring in 3D printed continuous fibre composite materials using the Phase field approach for fracture”, 2022, Composite Structures. https://doi.org/10.1016/j.compstruct.2022.116127»
- “Effect of tailored fiber deposition in 3D printed composites: application of an anisotropic phase field model”, 2023, TAFMEC. https://doi.org/10.1016/j.tafmec.2023.104030»
- "Effect of stacking direction and raster angle on the fracture properties of Onyx 3D printed components: a mesoscale analysis", 2023, TAFMEC. https://doi.org/10.1016/j.tafmec.2023.104228»
3D printing is gaining a huge interest both in industrial and academic environments. Anyway, the materials typically used in 3D printing need a deep study of their mechanical properties. The main aim of the PhD is the study of the mechanical properties of the structures realized with such innovative production technique. In addition, some reinforcement strategies based on optimization techniques are of primary interests, in order to generate a new generation of tougher structures.
Two parts are distinguished in this thesis. The first one is dedicated to the numerical study of the reinforcements strategies in 3D printed structures. The second one is related to the experimental study of the toughening mechanisms achieved by means of 3D printing.
The main aim of my work is to study the toughening mechanisms that can be achieved by means of 3D printing techniques. The first part was focused on the numerical assessment of these mechanisms, modelling the structures printed in 3D both using one or two materials. The second part is more experimental: we wanted to understand and see what was behind the toughening mechanisms achieved in by using 3D printing.
Conventional 3D printing uses thermoplastic filaments and powder made of ABS, PLA. The main drawback of the use of these materials are the mechanical properties, insufficient for many applications. To improve their performance, short fibers and platelets are added during the extrusion process, not achieving the ones of traditional composites, anyway. Continuous fiber 3D printing integrates, in the polymeric matrix, long fibers such as carbon fiber, fiberglass and Kevlar during the extrusion process, allowing the components printed in such way to achieve mechanical properties very close to the ones of their classical counterpart.
Of fundamental interest is to understand, first of all, whether the phase field tool is able to catch the crack deflection typical of the long fiber reinforced specimens. This was proved by means of a first study where polymeric material and long fibers are modelled as different materials. The study was extended to typical specimens of the mechanical and aeronautical world, like notched and holed tension specimens, see Figure 1.
Figure 1 Phase field simulation of the fracture process for: a) component without reinforcement, b) component with reinforcement.
The second part is focused on the improvement of the mechanical performance of 3D printed specimens by means of result driven optimization techniques, see Figure 2. The possibility to shape the reinforcement pattern in the 3D printed components allows an ad-hoc reinforcement, able to increase their mechanical resistance, given the loads they are supposed to endure. The concept has been applied to tension, shear and bending scenarios, demonstrating the efficiency of such procedure in many scenarios.
Figure 2 Improvement of strength for Open Hole Tension specimens by means of a tailored fibre deposition.
The third part is focused on the experimental investigation of the toughening mechanisms, see Figure 3 and 4. Bending specimens were printed with different configurations of stacking directions and raster angles to check their influence on the mechanical properties of the coupons. After a deep analysis of the fracture surfaces by means of a digital microscope, the best combination of printing parameters to ensure enhanced mechanical properties was found.
All the evidence, both numerical and experimental, could contribute to a larger adoption of the 3D printing technology both in the academic and industrial environment.
Figure 3 Printing configurations studied
Figure 4 Digital image of one of the fracture surfaces.
Date: Defended on 22/03/2024
Link to Open Access Repository: https://idus.us.es/handle/11441/158904»
Presentation: ESR02_Sangaletti_Simone»
All the developments I have made they can be applied in 3D printed materials for space applications.
Sara Jiménez Alfaro
"J’ai appris que la voie du progrès n’était ni rapide ni facile" - Marie Curie
ESR03: Fracture analysis of advanced layered ceramics. See details»
Hello, my name is Sara, I am from Seville (Spain). I studied the Bachelor of Aerospace Engineering and then the Master in aeronautical engineering. I am now finishing my PhD at Sorbonne Université, in the Institut Jean Le Rond d'Alembert. I am ESR3 in NewFrac.
A secret about me? I am very talkative!
University of Seville // Duration: 6 months (June - September 2021, September-October 2022)
At University of Seville I studied the Phase Field model, one of the two mechanical frameworks that are studied in the network to predict fracture mechanics. The main objective of this secondment was to apply the phase field model at different scales, comparing the results obtained with the ones analysed by the Coupled Criterion (in the framework of Finite Fracture Mechanics).
From my personal point of view, the secondment in Seville was an amazing experience. I had the opportunity to meet other PhD students from the network: Karthic (ESR1) , Simone (ESR2), Anatoli (ESR4), Zeng (ESR9), Sindhu (ESR11) and Juan (ESR12). Together with other PhD students in Seville, we made lots of trips together and we become close friends!
Safran // Duration 4 months (March-June 2023)
During this industrial secondment I have applied all the developments I have made during my PhD thesis. We have studied short fibres CMC (ceramic matrix composites), an advanced structure of ceramic material that is now under study by the company. I had the opportunity to live an amazing experience there, meeting other colleagues in the mechanical department. The most important thing I learnt is how to visualize an academic work to be applied in the industry, which I think is a key piece in the development of a project.
- NewFrac Conference – New Computational Strategies for Fracture, held in Porto, Portugal from 07th to 10th May, 2024
- EUROMECH COLLOQUIUM 635 - Finite Fracture Mechanics held in Lyon, France, from 12th to 14th September, 2023. Awarded by the “Best PhD Presentation”
- CFRAC 2023 - Seventh International Conference on Computational Modelling of Fracture and Failure of Materials and Structures, held in Prague, Czech Republic, from 21st to 23rd June, 2023.
- ICF15 - 15th International Conference on Fracture, held in Atlanta, Georgia, USA, from 9th to 19th June, 2023
- NewFrac & TC16 Joint Workshop – “Reaching Out”, held in Torino, Italy, from 17th to 20th January, 2023
- ESMC2022 – 11th European Solid Mechanics Conference, held in Galway, Ireland, from 4th to 8th July, 2022
- ECF23 - European Conference and Summer School on Fracture 2022 held in Funchal, Madeira, Portugal, from 25th June 2022 to 2nd July 2022
- NewFrac Workshop 2 – “Expanding Horizons”, held in Lucca, Italy, from 09th to 12th May, 2022
- IBCSI2022 – 5th Iberian Conference on Structural Integrity, held in Coimbra, Portugal, from 30th March to 1st April, 2022
- NewFrac Workshop 1 – “New Strategies in Computational Fracture Mechanics”, held in Seville, Spain, from 1st to 8th October, 2021
Dissemination
I was also invited to give a seminar at the University of Carlos III, where I could talk about my PhD thesis, see the link below: https://www.youtube.com/watch?v=YfXWCmIoj0g»
I have also taken part in the European Researchers Night during 3 years, an amazing experience that I really enjoyed.
- Baranova, S., Mogilevskaya, S. G., Mantič, V., & Jiménez-Alfaro, S. (2020). Analysis of the antiplane problem with an embedded zero thickness layer described by the Gurtin-Murdoch model. Journal of Elasticity, 140, 171-195. Analysis of the Antiplane Problem with an Embedded Zero Thickness Layer Described by the Gurtin-Murdoch Model | Journal of Elasticity (springer.com)»
- Jiménez-Alfaro, S., Villalba, V., & Mantič, V. (2020). Singular elastic solutions in corners with spring boundary conditions under anti-plane shear. International Journal of Fracture, 223, 197-220. Singular elastic solutions in corners with spring boundary conditions under anti-plane shear | International Journal of Fracture (springer.com)»
- Jiménez-Alfaro, S., & Leguillon, D. (2021). Finite Fracture Mechanics at the micro-scale. Application to bending tests of micro cantilever beams. Engineering Fracture Mechanics, 258, 108012. https://doi.org/10.1016/j.engfracmech.2021.108012»
- Jiménez-Alfaro, S., & Leguillon, D. (2022). Modelling of glass matrix composites by the Coupled Criterion and the Matched Asymptotics approach. The role of a single platelet. Theoretical and Applied Fracture Mechanics, 122, 103650. https://doi.org/10.1016/j.tafmec.2022.103650»
- Jiménez-Alfaro, S., Reinoso, J., Leguillon, D., & Maurini, C. (2022). Finite Fracture Mechanics from the macro-to the micro-scale. Comparison with the Phase Field model. Procedia Structural Integrity, 42, 553-560. https://doi.org/10.1016/j.prostr.2022.12.070»
- Jiménez-Alfaro, S., & Mantič, V. (2020). FEM Benchmark Problems for Cracks with Spring Boundary Conditions Under Antiplane Shear Loadings. Aerotecnica Missili & Spazio, 99(4), 309-319. FEM Benchmark Problems for Cracks with Spring Boundary Conditions Under Antiplane Shear Loadings | Aerotecnica Missili & Spazio (springer.com)»
- Jiménez-Alfaro, S., & Mantič, V. (2023). Crack tip solution for Mode III cracks in spring interfaces. Engineering Fracture Mechanics, 288, 109293. https://doi.org/10.1016/j.engfracmech.2023.109293»
Ceramic materials are widely used in the industry owing to their countless advantages, such as the resistance to corrosion or oxidation. However, they have a very low fracture toughness, which is related to the spontaneous brittle failure of the component. In this context, the main objective of this thesis is the consistent extension of numerical modelling tools in fracture mechanics for predicting crack nucleation and growth in advanced ceramics, with a special emphasis in the relationship between the micro and macro-scale characteristics within these materials. Two approaches are followed: the Coupled Criterion (CC) within the Finite Fracture Mechanics (FFM) framework and the Phase Field (PF) model for fracture.
Two parts are distinguished in this thesis. The first one is dedicated to the study of ceramics fracture properties at the micro-scale. In the second part we focus on the fracture analysis of brittle materials reinforced by a second constituent in the form of micro-platelets or short fibers, a kind of structure of high technological interest for advanced ceramics.
Ceramic materials are widely used in the industry owing to their countless advantages, such as the resistance to corrosion or oxidation. However, they have a very low fracture toughness, which is related to the spontaneous brittle failure of the component. In this context, the main objective of this thesis is the consistent extension of numerical modelling tools in fracture mechanics for predicting crack nucleation and growth in advanced ceramics, with a special emphasis in the relationship between the micro and macro-scale characteristics within these materials. Two approaches are followed: the Coupled Criterion (CC) within the Finite Fracture Mechanics (FFM) framework and the Phase Field (PF) model for fracture.
An inherent property of materials is an internal length frequently named as the Irwin length, that depends on the fracture properties. At the macro-scale, this length is small compared to the dimensions of the specimen. However, at the micro-scale it is of the same order of magnitude or even larger and can interact with the dimensions of the structure. In my PhD thesis this phenomenon is studied considering two different numerical tools. First, in the framework of FFM, a crack is assumed to jump a given finite length at onset, and the CC estimates that this length is proportional to the internal length of the material. On the other hand, in the PF model for brittle fracture there is a length related to the size of the damaged region, called the phase field length scale, that is also proportional to the internal length of the material.
Moreover, we study the answer brought by both the CC and the PF model when descending the scales from the cm-scale to the μm-scale and even nm-scale. This would help to better describe ceramic materials at the micro-scale, and therefore to enhance the design of advanced ceramics, which is commonly based on changing the micro-structure of classical ceramics to generate new materials with improved mechanical properties. One type of these new structures is deeply studied in my PhD, made of brittle matrices reinforced by short fibers or platelets. They are analyzed using numerical techniques that avoid the controversial conclusions obtained about fracture properties when descending the scales in ceramics.
Thus, we develop a computational tool to study the fracture behaviour of such composites, based on the connection between the micro- and the macro-scale. The aim of this tool is to provide an insight into the changes generated in the crack propagation when it encounters the reinforcing element, estimating the apparent fracture toughness of the composite as a function of design parameters.
To sum up, two parts are distinguished in this thesis. The first one is dedicated to the study of ceramics fracture properties at the micro-scale. In the second part we focus on the fracture analysis of brittle materials reinforced by a second constituent in the form of micro-platelets or short fibers, a kind of structure of high technological interest for advanced ceramics.
Date: Defended on 16/10/2023
Link to Open Access Repository: To be published by Sorbonne Univ.
Presentation: ESR03_Jimenez_Sara»
- CLEAN AND SUSTAINABLE MOBILITY»: The design tool I have developed during my PhD thesis has been applied to a material proposed by Safran company to enhance the performance of the engine and therefore to achieve climate neutrality by 2050
- EU SPACE POLICY»: All the developments I have made they can be applied in ceramics materials for space applications.
Anatoli A. Mitrou
"Imagination creates reality"
ESR04: Fracture of LFRP ultra-thin ply laminates in aeronautical applications. See details»
I am a musician at heart and an engineer by trait that really enjoys discovering new things. I have thus far already traveled quite a bit and can understand more languages than I can properly speak (oh well…beware!). I fell in love with flying age 5 and have since enjoyed almost all things aerospace related, with no one topic being my favorite, but would love to at some point work on a project that is completely novel and that will bring light to new knowledge, such as a personal favorite NASA’s Cassini-Huygens mission.
Sevilla // Duration: 6 months (Sept. 2021 - March 2022)
I was at the university of Seville for a total of 6 months starting in the fall of 2021. During that secondment my task was to work on the Phase Field formulation part of my work. It was a good opportunity to work with other ESR’s on a technical level as a couple of them were also there, ESR1, ESR2, ESR3, ESR9, ESR11, ESR12. With ESR2 especially, aka Simone Sangaletti, this sparked a joint venture to work together on a topic that eventually has now led to published work. With these ESRs we drove to some cool places in Andalucia tried food and experienced fun times through which strong friendships occured.
Madrid // Duration: 3 months (Sept. 2022 - Dec. 2022)
As part of FIDAMC in Madrid, a composite testing and manufacturing company, I had a very nice time. I got to interact with the experts in the field there and learn from them. I also got to do part of my testing there with them. It was overall nice to also get to meet and experience another Spanish city.
In total I have attended 9 international conferences and workshops, at which I presented each time the developments of my work during that time.
- NewFrac Conference – New Computational Strategies for Fracture, held in Porto, Portugal from 07th to 10th May, 2024
- COMPOSITES 2023 - 9th ECCOMAS Thematic Conference on the Mechanical Response of Composites, held in Trapani, Italy, from 12th to 14th September, 2023
- ICCM23 – International Conference on Composites Materials, held in Belfast, UK, from 30th July to 04th August, 2023
- CFRAC 2023 - Seventh International Conference on Computational Modelling of Fracture and Failure of Materials and Structures, held in Prague, Czech Republic, from 21st to 23rd June, 2023.
- ICF15 - 15th International Conference on Fracture, held in Atlanta, Georgia, USA, from 9th to 19th June, 2023
- NewFrac & TC16 Joint Workshop – “Reaching Out”, held in Torino, Italy, from 17th to 20th January, 2023
- ECF23 - European Conference and Summer School on Fracture 2022 held in Funchal, Madeira, Portugal, from 25th June 2022 to 2nd July 2022
- NewFrac Workshop 2 – “Expanding Horizons”, held in Lucca, Italy, from 09th to 12th May, 2022
- NewFrac Workshop 1 – “New Strategies in Computational Fracture Mechanics”, held in Seville, Spain, from 1st to 8th October, 2021
Attending these conferences and the extra interaction with experts was incredibly nice. I developed good soft skills and made more than a few nice connections. Additionally, I have attended all the NewFrac workshops, small internal almost conferences, that gave us the opportunity to collectively learn about each other’s work and given the more closed nature of these workshops I was able to develop a close relationship with some professors outside the network as well. Apart from all things professional, the travels attached and experiences and food that I tried during these events is something cherishable.
Dissemination
Moreover, I have taken part in the European Researchers’ Night during 3 years, an amazing opportunity to bring science closer to people who are not involved in the field.
- Modeling fracture of multidirectional thin-ply laminates using an anisotropic phase field formulation at the macro-scale». A Mitrou, A Arteiro, J Reinoso, PP Camanho. International Journal of Solids and Structures 273, 112221 (2023)
- Effect of tailored fiber deposition in 3D printed composites: application of an anisotropic phase field model». S Sangaletti, A Mitrou, IG García, A Arteiro. Theoretical and Applied Fracture Mechanics 127, 104030 (2023)
- Application of Composite Materials to Reduce Mass of Internal and External Exploration Habitat Structures». M Simon, L Carpenter, G Hrinda, A Bergan, J Samareh, A Mitrou. 49th International Conference on Environmental Systems. 2019
My work pertains to developing a tool for the macro-scale level analysis of Multidirectional Thin-ply laminates. The two methods proposed are the use of the Phase Field (PF) method and the coupled Finite Fracture Mechanics (FFM) criterion. The specific problem this was applied to was predicting the off-axis response of a range of lay-ups both concerning strength and fracture path.
Studying how materials used in airplanes break to be able to safely design and use them in new aircraft of the future. In order to use a certain material, you must know how and when it breaks. Thus, engineers like me work on creating methods and the tools to know how each material used on airplanes behaves, how much it can take before failing, to use them with confidence.
Date: Defended on 30/07/2024
Link to Open Access Repository: To be published by Porto Univ.
Presentation: ESR04_Mitrou_Anatoli»
- CLIMATE ACTION: My work is directly linked to the efforts made by the aerospace industry to improve their tools and materials used for more efficient aircraft that will help lead to more sustainable and efficient flight. Part form that my work con novel materials could also be extended to any application this material or these numerical techniques could lead to use of less “scrap” material and thus lead to more sustainable R&D and end products.
Camilla Zolesi
"Beauty is truth, truth beauty,—that is all Ye know on earth, and all ye need to know." from Ode on John Keats
ESR05: Nucleation and propagation of compressive cracks. See details»
I am a Ph.D. student with a deep enthusiasm for theoretical mechanics. My passion extends to both mechanics and sea sports. I am particularly enthusiastic about the untapped research prospects in modeling physical phenomena like and I aspire to make a contribution to this field. What captivates me in the scientific research and the sea is the fact that they both embody a sense of freedom despite the rigor required.
ETH Zürich, Switzerland // Duration: 6 months (Jun 2021 - Sept 2021 & Jun 2022 - Jul 2022), Supervisor: Prof. Laura De Lorenzis
We established a collaboration with ESR10 in order to sort the wealth of literature based on specific criteria pointed out during this preliminary analysis. We define these criteria as the ability to flexibly reproduce multi-axial strength and avoid interpenetration of crack faces, and so we perform a systematic review of some available models. Based on these concepts, we propose numerical benchmarks to evaluate the behavior of solutions in literature. In particular, the proposed tests provide an assessment of a phase field model for both nucleation and propagation.
Renningen, Germany // Duration. 4 months (Mar 2023 - Jun 2023), Supervisor: Dr. Fabian Welshinger.
In order to maximize the benefit of the researcher's secondment period at Bosch, a collaboration was initiated to compare the models developed for quasi-incompressible materials with experimental data on adhesive joints held by Bosch.
- NewFrac Conference – New Computational Strategies for Fracture, held in Porto, Portugal from 07th to 10th May, 2024
- CFRAC 2023 - Seventh International Conference on Computational Modelling of Fracture and Failure of Materials and Structures, held in Prague, Czech Republic, from 21st to 23rd June, 2023.
- 8th GAMM Workshop on Phase-field modeling, held in Zürich, Switzerland, from 6th to 7th February, 2023
- NewFrac & TC16 Joint Workshop – “Reaching Out”, held in Torino, Italy, from 17th to 20th January, 2023
- ECF23 - European Conference and Summer School on Fracture 2022 held in Funchal, Madeira, Portugal, from 25th June 2022 to 2nd July 2022
- CSMA2022 – 15éme Colloque National en Calcul des Structures, held in Giens, France, from 16th to 20th May, 2022
- NewFrac Workshop 2 – “Expanding Horizons”, held in Lucca, Italy, from 09th to 12th May, 2022
- NewFrac Workshop 1 – “New Strategies in Computational Fracture Mechanics”, held in Seville, Spain, from 1st to 8th October, 2021
Dissemination
European Researchers’ Night (organizer), NewFrac & Politecnico di Torino, Italy, (Sept 30, 2022), NewFrac & Universidad de Sevilla, Spain, (Sept 30, 2022 & Sept 24, 2021).
- F. Vicentini, C. Zolesi, P. Carrara, C. Maurini. L. De Lorenzis, On the energy decomposition in variational phase-field models for brittle fracture under multi-axial stress states, submitted to IJF (soon the link to the pre print)
Phase-field (PF) modeling of fracture is gaining popularity in the fracture mechanics community, particularly for its ability to generate cracks with arbitrarily complex geometries and topologies in two and three dimensions without the need for ad hoc criteria. The model first introduced in [1] has a clear connection with Griffith’s propagation criterion via Gamma convergence tools and further results [2] have shown that, in addition to propagation, it can quantitatively predict crack nucleation for mode-I loading. However, the initial model cannot reproduce with flexibility the experimentally measured strengths under multi-axial loads. Moreover, a modification is necessary to avoid the interpenetration of crack surfaces in compression and reflect the physical asymmetry of fracture behavior between tension and compression [3]. The project is inscribed in the study and analysis of these issues and limitations to broaden the applicability of PF model to multi-axial loads.
Fig. 1: Plate with hole test using the new model. A parameter is calibrated to obtain a crack parallel to the loading direction. The original phase-field model fails in reproducing such experimentally observable crack direction.
Phase-field modeling of fractures is a technique used to understand how materials break apart. It's becoming quite popular because it allows us to predict complex crack patterns in 2D and 3D without using additional rules.
But here's the catch: this model isn't great at explaining how materials break under different kinds of forces, like when you push or twist them. Our project is all about studying these issues and trying to make this model more useful for a wider range of situations where things break in different ways.