Prof. Anna Pandolfi, Professor of Structural and Material Mechanics at the Politechnical University of Milan (Italy), will give the SFB 1313 Anneliese Niethammer Lecture of the summer semester 2024 on June 18th 2024.
The title of her presentation will be:
Speaker: Prof. Anna Pandolfi, Politechnical University of Milan (Italy)
Title: "A coupled approach for diffused fracturing in porous brittle materials"
Date: June 18th 2024
Time: 4:00 pm CET
Place: Multi Media Lab (MML), U1.003, Pfaffenwaldring 61, 70569 Stuttgart, Campus Vaihingen.
Online Access: https://unistuttgart.webex.com/unistuttgart/j.php?MTID=ma767632d082b045ad5cf0f76cdf97166
Abstract
The mechanical behaviour of geomaterials cannot be disjoined from the flow of pore fluids. The mechanical response of rocks and soils subject to mechanical and hydraulic loads induces not only changes in stiffness and strength of the solid skeleton, but also in the porosity and permeability of the geomaterial, causing, in turn, redistribution of pore pressure, and again, modification on the stress state of the material, possibly inducing the enucleation of new fractures or the propagation of existing ones. A thorough understanding of the behaviour of such materials is important for many applicative aspects, ranging from civil, petroleum and mining engineering, geology and geophysics. For realistic simulations of the behaviour of fracturing porous media, together with a correct coupling procedure for the mechanical and hydraulic problem, it is also necessary a constitutive model for the material, able to reproduce the behaviour of existing cracks and the formation of new ones.
In this work we apply a brittle damage material model recently developed in [1] to the simulation of hydro-mechanical tests at different scales. The material model is based on the idea of distributed damage, described by a pattern of distributed equi-spaced and parallel cracks, and it has been implemented into a finite element code [2-3]. Unlikely most commercial software, the approach does not assume the existence of a unique sharp fault and is based on energetic consideration to identify the “optimal pattern” of the faults. The numerical solution of the coupled problem is achieved using a staggered approach, allowing the use of the most suitable algorithm for the solution of the equations involved (explicit approach for the non-linear, equilibrium equation, and direct approach for the continuity equation).
The code has been used for the simulation of a fracking test at the laboratory scale. The numerical results are in reasonably good agreement with the experiments. The code has also been used for the simulation of fracking jobs at the reservoir scale. A parametric study allowed assessing the influence of different operational parameters on the production of the reservoir.
References
[1] A. Pandolfi, S. Conti, and M. Ortiz. A recursive-faulting model of distributed damage in con_ned brittle materials. Journal of Mechanics and Physics of Solids Vol. 54: pp. 1972-20030, 2006.
[2] ML, De Bellis, G. Della Vecchia, M. Ortiz, A. Pandolfi. A linearized porous brittle damage material model with distributed frictional-cohesive faults. Engineering Geology, 215, 10-24, 2016.
[3] M. L. De Bellis, G. Della Vecchia, M. Ortiz and A. Pandolfi. A multiscale model of distributed fracture and permeability in solids in all-round compression. Journal of Mechanics and Physics of Solids Vol. 104: pp. 12-31, 2017.
About Anna Pandolfi:
Anna Pandolfi is a distinguished Professor of Materials and Structural Mechanics at the Politecnico di Milano, Italy, where she has been a faculty member since 1995. She earned her M.S. in Civil Engineering in 1984 and her Ph.D. in Mechanics in 2007. Over her career, she has published 66 international peer-reviewed papers and contributed to six book chapters. Her work is widely recognized, with a Web of Science h-index of 22 and over 2,300 citations.
She has held significant leadership roles, including serving as President of the Italian Group of Computational Mechanics (GIMC-AIMETA) and as a member of the Euromech Council. Prof. Pandolfi is also an honorary speaker at numerous international conferences and workshops.
Her collaborations extend globally, with current research partnerships at institutions such as Caltech, the University of Siegen, and the University of Nantes. She has advised numerous graduate students and postdoctoral researchers, many of whom have gone on to successful careers in academia and industry.
Prof. Pandolfi continues to contribute significantly to the field of mechanics through her research, teaching, and extensive involvement in the scientific community.
About Her Research:
Prof. Pandolfi's research spans a range of topics, including multiscale modeling of fracture and permeability, numerical analysis of corneal biomechanics, and the development of advanced materials like metaconcrete. She has been a regional associate editor for the International Journal of Fracture and a guest editor for several special issues in prestigious journals.
About the SFB 1313 Anneliese Niethammer Lecture Series
Anneliese Niethammer was the first female professor of the University of Stuttgart in 1947. The lecture series, dedicated to Anneliese Niethammer, is organised by the Collaborative Research Center (SFB) 1313 and takes place once a semester. Renowned international female researchers speak on relevant topics of current research in the research area of porous media.
