Simulating Spontaneous Shape Changes in Programmed Elastic Sheets

Thin soft sheets made from some elastic materials can undergo shape changes governed by parameters which are 'programmed' in the sheet.
These parameters describe, at each point, the stretching and bending the sheet will 'want' to undergo upon some form of 'activation'. This activation can take the form of heating, illumination, or biological growth, for example. The main aim of my project is to develop and utilise a novel simulation algorithm/code that simulates these shape changes, given a set of programmed parameters. Examples of systems this could be applied to include growing biological tissues (e.g. leaves), swelling hydrogels, and liquid crystal elastomers (LCEs). In the latter case, which will be the main focus, the programmed quantity is a 'director' pattern, that describes the local orientation of rod-like molecules. The simulation will be used as a predictive tool, aiding the design of director patterns that produce interesting or useful shape changes. The shape change in LCEs can be particularly dramatic and the resulting shapes can be strong for their size, allowing for the creation of soft machines controlled via light or heat. Such machines could act as lifters, grabbers, pushers, irises etc, with many potential applications in microfluidics, biomechanics, medicine, optics and engineering. I plan to also apply the simulation to growing sheets of tissue cells, to try to understand the formation of certain experimentally observed shapes.

My work will include both theoretical and computational aspects. I will design the numerical simulation algorithm with the help of my supervisor. I will write a C++ code from scratch to implement the algorithm. The design of new LCE director patterns will then involve theoretical analysis and pen-and-paper calculations, to either explore and discover patterns with interesting mathematical properties, or to produce patterns that will produce specific shape changes with specific applications in mind. For example, I have already been involved in designing a ring of LCE that contracts like an iris upon illumination, imitating the functioning of an eye. I have helped develop certain versions of this pattern, and done simulations to predict the exact shape change, which will be compared with collaborators' experiments

Computing, data and communications infrastructure have transformed modern life. They all require software, security and trained personnel to work effectively and it has become common to use the term e-Infrastructure to refer to the whole of this interconnected ecosystem. E-Infrastructure has become a major contributor to advances in science and technology and it is clear that no industry will be able to compete internationally unless it exploits e-Infrastructure at highest level. The proposed EPSRC Centre for Doctoral Training in Computational Methods for Materials Science is focused on the development of new functionality in existing software, and even entirely new codes that will address challenges in materials that cannot presently be addressed. The UK is making large capital investments in e-Infrastructure but these investments will only achieve a fraction of their potential impact unless investments are also made in software development. The CDT will primarily focus on software development for materials science, which is itself, of course, extremely broad. However, the training provided in numerical methods, modern software development techniques and the exposure to present and emerging computational hardware means that the students will have the skilled set to work in any area of software after their PhDs. Given the universally acknowledge lack of highly trained personnel in software development one of our most important impacts will be in providing nearly 80 people who can apply this training in industry, including the very large number of UK software-based SMEs, or academia. The emphasis of the training and subsequent research project in the CDT is on development of innovative new methods for materials modelling and these will have impact in both academia and industry in further expanding the capability of materials simulation and the range of phenomena and processes that can be simulated and/or the amount of information that can be extracted from experiments. Thus we expect the CDT to have a significant impact across a very broad spectrum of disciplines.