The Mechanics of Infrastructure Materials research group are looking to hire a Postdoctoral Research Associate (PDRA) to work in the development of new phase field-based models for predicting localised corrosion (pitting and stress corrosion cracking). The work is part of a wider project, led by Dr Emilio Martínez-Pañeda, that builds upon our recent JMPS work (https://doi.org/10.1016/j.jmps.2020.104254).
We have contributed to the Special Issue organised by the Royal Society on occasion of the centenary of Griffith's seminal paper with a paper revisiting phase field fracture methods and their connection with conventional fracture mechanics theory. I hope that you find it of interest. (https://royalsocietypublishing.org/doi/10.1098/rsta.2021.0021)
The Mechanics of Infrastructure Materials research group are looking to hire a Postdoctoral Research Associate (PDRA) to work in the EPSRC project NEXTGEM. The project, led by Dr Emilio Martínez-Pañeda, aims at combining phase field methods and electro-chemo-mechanics modelling to resolve the scientific challenges holding back the applicability of hydrogen embrittlement models.
I hope that the following work is of interest to you. We combine the phase field method with cohesive zone modelling to predict the fracture behaviour of fibre-reinforced composites across scales.
Dear iMechanicians, I hope that our latest JMPS paper is of interest to you. We show how the phase field paradigm can be extended to model localised corrosion (aqueous electrolyte-solid interface) and the associated damage mechanisms.
C. Cui, R. Ma, E. Martínez-Pañeda. A phase field formulation for dissolution-driven stress corrosion cracking. Journal of the Mechanics and Physics of Solids 147, 104254 (2021)
The Mechanics of Infrastructure Materials research group are looking to hire a Postdoctoral Research Associate (PDRA) to work in the EPSRC New Horizons project NanoHMAT. The project, led by Dr Emilio Martínez-Pañeda, aims at exploring high-risk high-gain approaches for developing a new generation of hydrogen embrittlement-resistant materials.
Dear iMechanicians. I hope that the following paper is of interest to you. We develop the first phase field formulation for fracture (and fatigue) in Shape Memory Alloys. Its potential is demonstrated by solving a variety of paradigmatic 2D and 3D boundary value problems, from R-curves to fatigue cracking of a NiTi biomedical stent.
M. Simoes, E. Martínez-Pañeda. Phase field modelling of fracture and fatigue in Shape Memory Alloys. Computer Methods in Applied Mechanics and Engineering 373 (2021) 113504
I hope some of you find of interest our latest Acta Mat. paper. We show that the concept of "beneficial traps" can enlarge by an order of magnitude the range of "safe loading frequencies" at which hydrogen embrittlement is not observed.
Analysis of the influence of microstructural traps on hydrogen assisted fatigue
I hope that the following paper is of interest to you. We use for the first time Gurtin (2004) gradient plasticity theory to investigate crack tip mechanics, revealing the existence of an elastic core adjacent to the crack tip, resembling a dislocation-free zone. Also, we show that the combination of strain gradient hardening and dislocation blockage can rationalise brittle fracture in elastic-plastic material interfaces.
I hope some of you find our recent JMPS paper interesting. We combine phase field fracture, hydrogen transport and strain gradient plasticity to provide a modern rationale to the mechanism of hydrogen enhanced decohesion.
A phase field model for elastic-gradient-plastic solids undergoing hydrogen embrittlement
Philip K. Kristensen, Christian F. Niordson, Emilio Martínez-Pañeda
Journal of the Mechanics and Physics of Solids, 143, 104093 (2020)
I hope the present work is of interest to you. We present a new formulation for resolving the electrochemical-diffusion interface in hydrogen embrittlement modelling
E. Martínez-Pañeda, A. Díaz, L. Wright, A. Turnbull
Generalised boundary conditions for hydrogen transport at crack tips
I hope the present work on two-scale modelling of hydrogen permeation is of interest to you. A post-print is available at www.empaneda.com
A. Díaz, I. I. Cuesta, E. Martinez-Pañeda, J. M. Alegre Analysis of hydrogen permeation tests considering two different modelling approaches for grain boundary trapping in iron International Journal of Fracture 223, 17-35 (2020)
I hope this paper is of interest to you. We show that quasi-Newton methods make monolithic phase field fracture implementations very robust. Convergence and computations times orders of magnitude smaller than the usual staggered approaches are demonstrated in complex problems such as unstable cracking, fatigue or dynamic crack branching.
I hope that some of you will find this work interesting. We show that early cracking occurs in slow strain rate tensile testing (SSRT), which compromises the capabilities of this popular experiment for measuring hydrogen embrittlement susceptibility.
On the suitability of slow strain rate tensile testing for assessing hydrogen embrittlement susceptibility
E. Martínez-Pañeda, Z. D. Harris, S. Fuentes-Alonso, J. R. Scully, J. T. Burns
Applications are invited for two Research Assistant (PhD candidates) or Research Associates (post-docs) positions at the University of Oviedo, in close collaboration with Imperial College London. Research Assistants will be appointed for 2 years while Research Associates will be appointed initially for one year, with the possibility of extending one more year. Conditional upon satisfactory progress, the researchers will have the opportunity to divide their time between the University of Oviedo and Imperial College upon their convenience.
Please find below a paper, co-authored with Ivan Cuesta and Norman Fleck, on the mode II fracture of elastic-plastic sandwich layers. The paper is part of the special issue in the Journal of Applied Mechanics dedicated to John Hutchinson's 80th anniversary and the Century Fracture Mechanics Summit.
Applications are invited for a PhD scholarship at Imperial College London. The work will be conducted in close collaboration with the University of Cambridge, with the student being supervised by Dr Emilio Martínez Pañeda (main supervisor), Prof Catherine O'Sullivan (Imperial College) and Prof Norman Fleck FRS FREng (University of Cambridge).
The project aims at developing new theoretical and computational micromechanics-based models for rocks and porous media. More details of the project are given here:
We would like to invite you to submit a contribution for the Minisymposium on “Analysis and Methods for the Simulation of Deformation, Failure and Coupled Processes Across Scales” (description below), organized for the 2020 International Conference of the Engineering Mechanics Institute, April 24-26, at Durham, UK.
Applications are invited for a PhD scholarship at the University of Oviedo (Spain). The work will be conducted in close collaboration with Imperial College London. The PhD studentship is part of the MICROROCK project, which aims at developing a new generation of micromechanics-based models for predicting rock fracture. A competitive salary is offered and the position is open to international candidates. Further details are provided below and in the attached PDF.
PhD post in Computational Mechanics for porous media at the University of Oviedo, Spain
Applications are invited for a PhD scholarship at Imperial College London. The project will involve the development of novel computational tools to unravel fracture mechanics challenges across disciplines. The student will join the Mechanics of Infrastructure Materials Lab, led by Dr Emilio Martínez-Pañeda.
I hope some of you will find this work interesting. We present a new Weibull framework for cleavage fracture that incorporates strain gradient plasticity and can estimate the three parameters of Weibull-type models without any prior assumptions. A post-print is available at www.empaneda.com
Gradient-enhanced statistical analysis of cleavage fracture
I hope some of you may find this work interesting. We show, analytically and numerically, that strain gradient plasticity predicts the existence of an inner elastic field adjacent to the crack tip, reminiscent of a dislocation-free zone. The fact that elastic strains dominate plastic strains near the crack tip implies a paradigm-shift with respect to previous crack tip asymptotic studies in plasticity and gradient plasticity, which neglect elastic strains.
I hope some of you will find our recent paper in the Journal of the Mechanics and Physics of Solids interesting. The Abaqus user element (UEL) subroutine developed to implement strain gradient plasticity theories with energetic and dissipative higher order stresses (Gudmundson 2004, Fleck and Willis 2009) can be downloaded from www.empaneda.com/codes
The role of plastic strain gradients in the crack growth resistance of metals
Emilio Martínez-Pañeda, Vikram S. Deshpande, Christian F. Niordson, Norman A. Fleck
Applications are invited for a PhD scholarship at Imperial College London. The project will involve the development of novel computational tools to unravel fracture mechanics challenges across disciplines. The student will join the Mechanics of Infrastructure Materials Lab, led by Dr Emilio Martínez-Pañeda.
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