Materials Engineering

Modelling the mechanical behaviour of MOF materials using quantum mechanics

The aim of the project is to employ first-principles density functional computations to elucidate complex structure-mechanical property correlations in hybrid materials. The study will encompass Metal-Organic Framework (MOF) materials from different families, whose framework architectures, topologies, and chemical affinities can be distinctively different. The project will involve also some experimental studies. For example, the ab initio predictions will be corroborated with in-situ neutron scattering experiments and Terahertz spectroscopy, to be carried out at ISIS and Diamond synchrotron at Rutherford Appleton Laboratory.

People: Jin-Chong Tan, Matthew Ryder

Sponsors: EPSRC DTA, STFC

Date: October 2013–September 2017

Novel nanocomposite materials for clean energy and environmental remediation

The project focuses on the development of a novel group of polymer-based nanocomposites incorporating metal-organic framework (MOF) nanoparticles. Potential applications of such nanocomposites will include gas separations, volatile radioiodine trapping and water purification. New thin-film membranes will be designed, fabricated, and characterised in terms of their mechanical, thermal, and other functional properties. Detailed studies will be performed to address fundamental questions associated with the thermo-mechanical and environmental stability of such novel nanomaterials, which are key to practical engineering applications.

People: Jin-Chong Tan, Mahdi Mahmoud

Sponsor: Yayasan Khazanah

Date: October 2013–April 2017

Thin-film MOF materials for future microelectronics

The project focuses on the development of novel nanostructured materials based on Metal-Organic Frameworks (MOFs) for microelectronics, lighting, and sensing applications. Thin-film structures, coatings, and nanocomposites of multifunctional MOFs will be designed and fabricated to yield two- and three-dimensional architectures featuring numerous structural topologies and chemical functionalities. Central to successful device integration, fundamental properties encompassing the electrical, electronic, thermo-mechanical, and optical characteristics of these novel systems will be studied to gain insight into structure-property relationships fundamental to future device performance.

People: Jin-Chong Tan, Abhijeet Chaudhari

Sponsor: Samsung GRO

Date: January 2014–April 2017

Understanding and Improving Ceramic Armour Materials

This project focuses on improvement of experimental techniques for characterisation of strain rate dependent behaviour of ceramics for armour applications as well as on development of computational methodology for simulation of strain rate dependent behaviour of several ceramic materials while aiming to determine if manufacturing the materials using nano-scale powders offers potential to develop better armour systems.

People: Nik Petrinic, Richard Todd, Simone Falco, Claire Dancer, Emilio Lopez-Lopez

Sponsor: EPSRC, Dstl

Date: April 2009-December 2013

Composite, Hybrid & Multiscale Materials

Our research interests are focussed on the thermo-mechanical behavior of novel materials, such as Metal-Organic Frameworks (MOFs), polymer-based nanocomposites, 2D nanosheets, porous solids, inorganic-organic hybrids, and multi-functional coatings. We design and develop these novel materials for a wide range of functional and structural applications, ultimately to meet current and future challenges in energy, sustainability and healthcare. In our work, we make extensive use of state-of-the-art nanomechanical characterisation techniques (nanoindentation, AFM, SPM), spectroscopy, neutron scattering, and X-ray diffraction, in combination with computational modelling (DFT, FEM) to gain insights into fundamental structure-property relationships of complex nanostructured materials.

People: Jin-Chong Tan

Sponsor: EPSRC

Date: November2012-October2014

Development of multi-scale modelling methodology for simulation of rate dependent behaviour of titanium alloys

This project focuses on the understanding of the effect of geometric and physical aspects of material microstructure upon the strain rate dependent behaviour of titanium alloys at macroscopic scale.  Observation and quantification of the response to well controlled dynamic loading regimes and detailed modelling of thus characterised behaviour are carried out in close collaboration with material manufacturers in order to enable design of alloys with advanced/controlled response to impact loading.

People: Nik Petrinic, Benjamin Cousins

Sponsor: EPSRC, TIMET

Date: October 2010-March 2015

Investigation of texture dependent ballistic behaviour of titanium alloys

This project focuses on the understanding of the effect of material microstructure upon the ballistic properties of titanium alloys.  Microscopic characterisation of samples following rapidly applied loading (e.g. plate penetration, Taylor impact, etc.) is undertaken in order to provide better understanding of deformation and failure mechanisms for design of containment systems.

People: Nik Petrinic, Clive Siviour, Euan Wielewski

Sponsor: TIMET, Rolls-Royce

Date: January 2008-December 2011

Partners: Rolls-Royce, Airbus, Smiths Aerospace, BAE Systems, Imperial College

The objective of this project is to develop improved experimental methods for characterisation of CFRP composites and improved numerical models for simulation of the observed and measured behaviour.  A particular focus is on development of stable algorithms for simulation of damage propagation in laminated CFRP composites for lightweight fan applications.  The experimental programme is providing data for constitutive models at several length scales.

People: Nik Petrinic, Clive Siviour, Peifeng Li

Sponsor: DTI, Rolls-Royce

Date: July 2006-April 2010

Development of methodology for characterisation and predictive modelling of 3D reinforced composites

The objective of this research is to develop two-scale experimental procedures and numerical methods for simulating the response of 3D reinforced composites to impact loading.  A hierarchical ‘bottom-up’ approach has been used to develop macroscopic (continuum) failure criteria and damage evolution algorithms and a ‘top-down’ approach is used to optimise the material’s micro-structure.  A methodology for experimental characterisation of the individual components of 3D reinforced composites has been developed.  This focuses on resin systems, fibre yarns and on the interface between the two at meso-scale.  Implementation of such physically based constitutive modelling framework is an integral part of the project.  Virtual experiments are being used to simulate the behaviour of specific material architectures and complement the experimental work.  This approach has been applied to simulate the experimentally quantified response of composite sub-components to impact loading carried out in controlled laboratory conditions.

People: Nik Petrinic, Clive Siviour, Robert Gerlach

Sponsor: Rolls-Royce

Date: September 2006-January 2010

Impact Performance and Shock From Advanced Composites Technology (IPSoFACTo)

Development of new artificial bird material for bird strike on jet engine fan blades (STEFAN)

The main objective of this research is to develop novel artificial material whose behaviour will be qualitatively and quantitatively comparable to that of real birds in aeroengine impacts.  A secondary objective is to improve experimental methods for characterisation of such material(s) and numerical methods for predictive modelling of material behaviour.  A new hybrid material has been developed which comprises cellulose sponge and low density gelatine.  This has exhibited excellent behaviour when compared with real bird tissue.  Full experimental characterisation for generation of data for constitutive modelling is being carried out.  Numerical models based on a Lagrangian monolithic solid and on an assembly of particles are being developed to enable accurate simulation of bird strike events.

People: Nik Petrinic, Stefan Schwindt

Sponsor: CSL-IBRG

Date: September 2004-October 2007

Materials World Network - Domain Evolution in Ferroelectrics

This project is an international collaboration between University of Texas, Austin, and University of Oxford, UK. Ferroelectric crystals have applications as sensors, actuators and memory devices. Their behaviour in these applications is strongly governed by defects in the crystals such as domain walls. Understanding of these defects is at present held back by a lack of experimental data that are carefully matched to -  and thus can directly evaluate the predictions of - current models.
During the project, 3-dimensional mapping of domain structure using synchrotron X-ray diffraction will be carried out. Material configurations will be chosen to capture features such as domain needle formation, and domain nucleation near electrodes or inclusions. This will provide direct observations of the evolution of domain structure. Existing phase field models, extended to 3-dimensions will then be used to explore the observed configurations. Piezo-force microscopy and scanning electron microscopy will be used to evaluate model predictions at surfaces. The outcomes of the project will contribute at a fundamental level to the understanding of domain structure evolution, fracture, and toughening in ferroelectric crystals.

People: Dan Sui, \kwanlae Kim, Chad Landis (University of Texas, Austin)

Sponsor: EPSRC (UK), NSF (US)

Date: April 2010-April 2013 (Ongoing)

Designing with single crystal piezoelectrics and ferroelectrics

In the last 15 years, the field of functional materials with applications in sensors, actuators and smart materials, has expanded rapidly. Central to this development are piezoelectric materials which offer solid state actuation and sensing under direct electrical control. However, the fundamental issues of designing with and modelling of bulk single crystals remain largely unaddressed. Although many of the potential applications are piezoelectric in nature, the greatest strains are achieved at high field levels, which can induce both ferroelectric switching and phase transformations. At present, applications are severely limited by the issue of robustness: internal stresses give rise to cracks that grow in low-cycle fatigue. Yet there is no reliable model for the internal stress state of large single crystals. Similarly, a predictive understanding of the behaviour of ferroelectric single crystals under combined electrical, mechanical and thermal loads is needed. Such an understanding would enable the engineering design process for existing single crystal piezoelectrics, and would be equally applicable in the future to Lead-free piezoelectric single crystals that have the same underlying mechanisms of piezoelectricity and ferroelectric switching.

People: Prashant Potnis, Nien-Ti Tsou, Ananya Renuka Balakrishna

Sponsor: EPSRC

Date: October 2007-March 2011 (Ongoing)

Additional information:
    http://www.eng.ox.ac.uk/tan