Research Projects: Multiscale Materials Modelling

109 SIMULATING THE GROWTH OF BIOMATERIALS
Supervisor: Professor J Harding

Minerals in biological systems (such as shells, teeth and bones) grow into complex shapes, often nothing like the shapes expected from conventional crystal chemistry. Somehow, organic molecules in the environment where the mineral grows are controlling this. It is likely that the mineral begins as a soft, hydrated, amorphous material and only later becomes a hard, crystalline materials. This project will use a range of simulation techniques to investigate how a variety of organic molecules can control the growth of carbonates and phosphates. This project is linked to collaborations with experimental groups both in the UK and elsewhere. Most of the codes required to do this have already been written, but there will be possibilities for people to develop programming skills if they so wish.

110 SIMULATING DIFFUSION IN CERAMICS AND MINERALS
Supervisor: Professor J Harding

How fast atoms move and where they end up is a major issue in understanding (and so controlling the properties of ceramics). The first is the problem of diffusion; the second the problem of segregation. This project will investigate the mechanisms of diffusion for a range of ceramics from perovskites to pyrochlores and garnets. It will also consider the segregation of atoms and ions to surfaces and grain boundaries and what difference this makes to the properties of these structures. A range of static and dynamic simulation methods will be used including ab initio methods. Depending on the materials chosen, the project could link to a range of experimental work in the Department: from batteries and ferroelectric materials to nuclear waste disposal. The codes to do the calculations are already exist, but there will be opportunities for writing scripts and codes if people are interested.

111 NUMERICAL MODELLING APPLIED TO DEEP GEOLOGICAL DISPOSAL OF NUCLEAR WASTE
Supervisors: Dr K P Travis and Professor F G F Gibb

Disposal in deep boreholes is emerging as a potentially better alternative to mined repositories for the geological disposal of heat-generating high-level nuclear wastes. In order to predict the behaviour of the waste forms and materials involved, and make performance assessments of the disposal, it is necessary to combine sophisticated numerical modelling studies with a programme of experimental work.
This project will build on our existing work which has concentrated on modelling the conductive flow of heat in realistic waste disposal scenarios using finite difference methods, extending it to cover heat transfer by convection and modelling container failure. The project requires a high competency in mathematics and would suit students whose first degree is in Physics/Applied Mathematics/materials Science/Chemistry or an appropriate engineering discipline.

112 MODELLING MATERIALS FAILURE USING SMOOTH PARTICLE APPLIED MECHANICS (SPAM)
Supervisor: Dr K P Travis

Smooth Particle Applied Mechanics (SPAM) is a quite general simulation method which uses particles to solve problems in continuum mechanics. The basic idea is to express all of the continuum field variables (density, stress, heat flux etc) on a grid composed of moving particles. SPAM is best suited to solving problems which present extreme difficulty for the more usual continuum methods such as Finite Elements (FE), Finite Differences (FD); The FE approach has problems when large scale irregular deformations are involved while the FD approach runs into difficulty when there are moving boundaries resulting from materials flow. SPAM has been used in a wide variety of applications such as cutting and machining, understanding the stability of naval vessels to waves, the dynamics of ice in the Arctic Ocean and even problems in Astrophysics. It also shows great potential for solving problems in Materials Engineering, particularly material failure.