Welcome
In our group, we combine theoretical, computational and experimental methods to study the mechanical behaviour of materials. Our primary focus is on material degradation and multi-physics problems, with diverse applications in science and technology - from batteries to wind turbine structures. Take a look at who we are in the People tab; read more about some of our ongoing research activities in the Research tab; see our latest papers (and their associated codes) in the Publications tab; check our experimental resources in the Facilities tab; and feel free to download and use our Codes.
There are numerous opportunities for establishing a connection and for joining Oxford's Mechanics of Materials Lab. Inquiries are welcomed.
Recent news:
November 2024: We have a postdoc vacancy on computational solid mechanics. For application and details see here.
October 2024: We have a PhD vacancy on hydrogen embrittlement testing (ERC Starting Grant ResistHfracture). For application and details see here.
August 2024: Our PI, Prof Emilio Martinez-Paneda, has been awarded IACM's John Argyris Award. For more details see here.
July 2024: New postdoc vacancy to work on computational models for concrete crushing. For application and further details see here.
June 2024: Our PI, Prof Emilio Martinez-Paneda, has been awarded ECCOMAS's Zienkiewicz Award. For more details see here.
May 2024: We have been funded a research project to support Ukraine's recovery. For more details see here.
March 2024: New postdoc vacancy to work on phase field modelling of corrosion fatigue. For application and further details see here.
February 2024: New summer undergraduate intern vacancy to work on materials oxidation. For application and further details see here.
January 2024: Awarded a grant by EPSRC/Supergen ORE Hub. A postdoc position will be advertised soon.
November 2023: New postdoc vacancy to develop hydrogen-assisted fracture models. For application and further details see here.
September 2023: We have been awarded an ERC Starting Grant (ResistHfracture). Postdoc and PhD positions will be advertised soon.
Recent papers
Unravelling the interplay between steel rebar corrosion rate and corrosion-induced cracking of reinforced concrete
Accelerated impressed current testing is the most common experimental method for assessing the susceptibility to corrosion-induced cracking, the most prominent challenge to the durability of reinforced concrete structures. Although it is well known that accelerated impressed current tests lead to slower propagation of cracks (with respect to corrosion penetration) than in natural conditions, which results in overestimations of the delamination/spalling time, the origins of this phenomenon have puzzled researchers for more than a quarter of a century. In view of recent experimental findings, it is postulated that the phenomenon can be attributed to the variability of rust composition and density, specifically to the variable ratio of the mass fractions of iron oxide and iron hydroxide-oxide, which is affected by the magnitude of the applied corrosion current density. Based on this hypothesis, a corrosion-induced cracking model for virtual impressed-current testing is presented. The simulation results obtained with the proposed model are validated against experimental data, showing good agreement. Importantly, the model can predict corrosion-induced cracking under natural conditions and thus allows for the calculation of a newly proposed crack width slope correction factor, which extrapolates the surface crack width measured during accelerated impressed current tests to corrosion in natural conditions.
Influence of dislocation cells on hydrogen embrittlement in wrought and additively manufactured Inconel 718
Influence of dislocation cells on hydrogen embrittlement in wrought and additively manufactured Inconel 718
Hydrogen embrittlement (HE) is a major issue for the mechanical integrity of high-strength alloys exposed to hydrogen-rich environments, with diffusion and trapping of hydrogen being critical phenomena. Here, the role of microstructure on hydrogen diffusion, trapping and embrittlement in additively manufactured (AM) and wrought Inconel 718 is compared, revealing the key role played by dislocation cells. Trapping behaviour in hydrogen-saturated alloys is analysed by thermal desorption spectroscopy and numerical simulations. A high density of hydrogen traps in cell walls, attributed to dense dislocations and Laves phases, are responsible for the local accumulation of hydrogen, causing significant loss in strength, and triggering cracking along dislocation cell walls. The influential role of dislocation cells alters fracture behaviour from intergranular in the wrought alloy to intragranular for the AM alloy, due to the large proportion of dislocation cells in AM alloys. In addition, the cellular network of dislocations accelerates hydrogen diffusion, enabling faster and deeper penetration of hydrogen in the AM alloy. These results indicate that the higher HE susceptibility of nickel superalloys is intrinsically associated with the interaction of hydrogen with dislocation walls.
Ice viscosity governs hydraulic fracture that causes rapid drainage of supraglacial lakes
Ice viscosity governs hydraulic fracture that causes rapid drainage of supraglacial lakes
Full-thickness crevasses can transport water from the glacier surface to the bedrock where high water pressures can open kilometre-long cracks along the basal interface, which can accelerate glacier flow. We present a first computational modelling study that describes time-dependent fracture propagation in an idealised glacier causing rapid supraglacial lake drainage. A novel two-scale numerical method is developed to capture the elastic and viscoelastic deformations of ice along with crevasse propagation. The fluid-conserving thermo–hydro–mechanical model incorporates turbulent fluid flow and accounts for melting and refreezing in fractures. Applying this model to observational data from a 2008 rapid-lake-drainage event indicates that viscous deformation exerts a much stronger control on hydrofracture propagation compared to thermal effects. This finding contradicts the conventional assumption that elastic deformation is adequate to describe fracture propagation in glaciers over short timescales (minutes to several hours) and instead demonstrates that viscous deformation must be considered to reproduce observations of lake drainage rates and local ice surface elevation changes. As supraglacial lakes continue expanding inland and as Greenland Ice Sheet temperatures become warmer than −8 °C, our results suggest rapid lake drainage events are likely to occur without refreezing, which has implications for the rate of sea level rise.
A nonlinear phase-field model of corrosion with charging kinetics of electric double layer
A nonlinear phase-field model of corrosion with charging kinetics of electric double layer
<jats:title>Abstract</jats:title>
<jats:p>A nonlinear phase-field model is developed to simulate corrosion damage. The motion of the electrode-electrolyte interface follows the usual kinetic rate theory for chemical reactions based on the Butler-Volmer equation. The model links the surface polarization variation associated with the charging kinetics of an electric double layer (EDL) to the mesoscale transport. The effects of the EDL are integrated as a boundary condition on the solution potential equation. The boundary condition controls the magnitude of the solution potential at the electrode$-$electrolyte interface. The ion concentration field outside the EDL is obtained by solving the electro$-$diffusion equation and Ohm's law for the solution potential. The model is validated against the classic benchmark pencil electrode test. The framework developed reproduces experimental measurements of both pit kinetics and transient current density response. The model enables more accurate information on corrosion damage, current density, and environmental response in terms of the distribution of electric potential and charged species. The sensitivity analysis for different properties of the EDL is performed to investigate their role in the electrochemical response of the system. Simulation results show that the properties of the EDL significantly influence the transport of ionic species in the electrolyte.</jats:p>