Vacancies

PhD project 1 – A symbolic-numeric integrative modelling framework for skin biophysics

Background:  Besides the brain, no other organ of the human body plays such a central role in our everyday biological and social life than the skin [1-2]. It is the first line of defence against the external environment and this vital physical interface controls many types of exchanges between our inner and outer worlds. These exchanges take the form of mechanical, thermal, biological, chemical and electromagnetic processes which typically do not operate in isolation but are rather parts of a very dynamic system featuring complex non-linear feedback mechanisms. Computational modelling of skin biophysics is playing an ever growing role in academic and industrial research (across many sectors from medical and biological sciences, through personal care and medical products to consumer electronics and vehicle safety).

The project: To date, physics-based modelling of the skin has been fragmented due to the absence of a unified computational environment where “plug and play” multiphysics/multiscale finite element formulations (e.g. constitutive models, contact algorithms) could seamlessly be integrated as new theories develop and new experimental data come to life. Another factor hindering the exploitation of new mathematical model is the complexity and time-consuming aspect of implementing new finite element code or modifying legacy code.

For this project it is proposed to use a mature symbolic-numeric environment (AceGen-AceFEM [3]) integrated within the powerful environment of Mathematica® to design a modular modelling platform that will address current shortcomings in skin modelling (or, for that matter, for any types of complex structural material). The framework will exploit robust multi-mode differentiation tools and AceGen symbolic/numeric/stochastic algorithms to optimise code generation. From a single symbolic description of a finite element/any numerical formulation, optimised C, Fortran, Matlab or Mathematica code can be generated (controlled by a simple flag switch). Software interfaces between this developed environment and open source/commercial finite element environments (e.g. FEniCS, FireDrake, Deal II, Abaqus) will be produced to gain access to large scale parallel computing capabilities available at the University of Southampton and to maximise impact of this research.

Although significant efforts will go in the development of the modelling platform, a number of scientific questions/hypotheses about the mechanobiology of skin, particularly in ageing, will be addressed (e.g. the role of cell hydration levels across the viable epidermis on the multiscale mechanics of the epidermis).

[1] Mathematical and computational modelling of skin biophysics – a review, 2017. Proc. Roy. Soc. A (invited contribution), submitted

[2] Limbert, G. 2014, In Computational Biophysics of the Skin (ed. B. Querleux), pp. 95-131. Singapore, Pan Stanford Publishing Pte. Ltd.

[3] Korelc, J. & Wriggers, P. 2016 Automation of Finite Element Methods. Springer, First edition, 346 pages.

The ideal applicant: We are looking for an applicant with a background in applied mathematics, physics, engineering mechanics, or computer science with strong interest and/or skills in programming and an appetite to independently learn and research across conventional discipline boundaries. An important part of this project is its integration within our existing team working on skin biophysics and material modelling so being a team player is essential.

The successful candidate will work in a stimulating research environment, supported by world-leading organisations such as Procter & Gamble, Rolls Royce and the US Air Force and will be encouraged to work with our international academic and industrial collaborators in Europe, South Africa, New Zealand, Singapore and the USA.

How to apply: If you wish to discuss any details of the project informally, please contact Georges Limbert, Email: g.limbert [ @ ] soton.ac.uk Tel: +44 (0) 2380 592381

PhD project 2 – Design and optimisation of bio-inspired programmable surfaces with active materials

Background: In Nature, a number of animals and plants have evolved the ability to exploit patterned surfaces at various scales (e.g. Lotus flower, shark cuticles) to their advantages. Dynamic or adaptive patterned surfaces are very desirable as they can be adapted to specific contexts, operating conditions and environments.Cephalopods such as octopus, squid and cuttlefish possess some of the most striking abilities in the animal kingdom: camouflage via rapid colour change and, of particular relevance for this project, adaptive change of the three-dimensional texture of their skin. Their skin acts as a programmable morphing soft surface.In an engineering context, this type of functional ability can open up a vast array of practical applications from programmable haptic surfaces, morphing skin to control hydro-/aerodynamic drag (i.e. tunable friction) through antibiofouling strategies, to flexible electronics and tissue engineering and regenerative medicine.

The project: In this research, it is proposed to explore the use of soft active materials that respond to external stimuli in a controlled manner to induce various levels of potentially large surface deformation. Soft active materials respond to an external stimulus to perform a function or exhibit a change in material properties. Examples include dielectric elastomers that deform under electricity and force, and hydrogels that swell under a change in temperature or pH value. The proposed research aims to understand the physical mechanisms behind surface instabilities and to achieve enhanced functions by harnessing or suppressing instabilities through the development of a robust and efficient finite element environment featuring integrated optimisation techniques and robust modelling of surface instabilities (this will involve significant code development). We aim to model how coupled fields such as stress, electric field, and chemical potential interact together to cause deformation and instabilities in such materials. Theoretical modelling and numerical simulations will be performed to better understand such coupled responses. It is anticipated that the numerical tools to be developed may advance the understanding of surface patterning, and also facilitate the design of new materials and structures.

The ideal applicant: We are looking for an applicant with a background in physics, engineering mechanics, mathematics, or computer science, and an appetite to learn and research across conventional discipline boundaries. An important part of this project is its integration within our existing team working on skin biophysics and material modelling so being a team player is essential.

The successful candidate will work in a stimulating research environment, supported by world-leading organisations such as Procter & Gamble, Roche, Rolls Royce and the US Air Force and will be encouraged to work with our international academic and industrial collaborators in Europe, South Africa, New Zealand, Singapore and the USA.

How to apply: If you wish to discuss any details of the project informally, please contact Georges Limbert, Email: g.limbert [ @ ] soton.ac.uk Tel: +44 (0) 2380 592381