Computational Mechanics

Electrophysiological-mechanical coupled pulses in neural membranes: a new paradigm for clinical therapy of SCI and TBI (NeuroPulse)

NeuroPulse will build the foundations of a new generation of disruptive and enabling healthcare technologies by exploring and using the interaction between the mechanical vibrational properties of neurons - a specialised cell in the body that transmits nerve impulses - and their electrophysiological functions. This endeavour is set to benefit the medical community in the diagnosis, prognosis, and treatment of Traumatic Brain Injury and Spinal Cord Injury, both major, global public health issues, while providing new avenues for non-invasive electrophysiological control, such as pain management.

People: Antoine Jerusalem

Sponsor: EPSRC Healthcare Technologies Challenge Awards

Date: May 2016-May 2020

Mathematical and Computational Modelling for Neuron Growth

The project aims at developing mathematical and computational models of the mechanics, growth, and remodelling  of neurones. In this project, we build new microscopic and macroscopic  models for axonal growth and implement them by developing numerical methods for evolving continuum bodies. This work is done in collaboration with the Mathematical Institute and the Department of Engineering Sciences.

People: Julian A. Garcia Grajales, Antoine Jerusalem, Alain Goriely

Sponsor: King Abdullah University of Science and Technology (KAUST) Global Research Partnership

Date: June 2014-June 2016

Computational Multiscale Neuron Mechanics (COMUNEM)

The last few years have seen a growing interest in computational cell mechanics. This field encompasses different scales ranging from individual monomers, cytoskeleton constituents, up to the full cell. Its focus, fuelled by the development of interdisciplinary collaborative efforts between engineering, computer science and biology, until recently relatively isolated, has allowed for important breakthroughs in bio-medicine/engineering or even neurology. However, the natural “knowledge barrier” between fields often leads to the use of one numerical tool for one bioengineering application with a limited understanding of either the tool or the field of application itself. Few groups, to date, have the knowledge and expertise to properly avoid both pits. Within the computational mechanics realm, new methods aim at bridging scales and modelling techniques; from density functional theory up to continuum modelling on large scale parallel supercomputers. To the best of the knowledge of the author, a thorough and comprehensive research campaign aimed at bridging scales from proteins to the cell level while including its interaction with its surrounding media/stimulus is yet to be done. Among all cells, neurons are at the heart of tremendous medical challenges, and an increased understanding of the intrinsic coupling between mechanical and chemical mechanisms in such cell is of drastic relevance. I thus propose here the development of a neuron model constituted of length-scale dedicated numerical techniques, adequately bridged together. The model will be used for two specific applications: neuron migration/growth and electrophysiological-mechanical coupling in neurons. Upon completion of the project, this multiscale computational framework will be made available to the bioengineering and medical communities to enhance their knowledge on neuron deformation, growth, electro-signaling and thus, on slowly evolving damaging diseases (Alzheimer’s disease, epilepsy), as well as more direct damages such as traumatic brain injuries.

People: Antoine Jerusalem

Sponsor: ERC Starting Grant

Date: May 2013-April 2018

Numerical modelling of shockwave interaction with kidney cells

Shock waves have been used medically in lithotripsy (i.e. fragmenting kidney stones) and the treatment for musculoskeletal indications. However, the shock waves can result in undesired damage to healthy tissue. Shock waves also show great potential in cancer therapy by mechanically destroying tumour cells or enhancing sonoporation to effect therapeutic drug delivery. However, the efficacy of these applications and the involved mechanisms are poorly understood. Our numerical work is aimed at understanding the interaction of shock waves and tissue at the cellular level.

In lithotripsy the goal is to minimise soft-tissue injury—an unwanted side-effect from the procedure. For the other therapeutic applications to focus is on understanding the mechanisms of action and optimising the therapeutic effect on the target cells whilst minimising the impact on healthy cells. This work focuses initially on kidney tissue which has both lithotripsy and cancer applications. However, the model can be extended to others organs.

People: Antoine Jerusalem, Robin Cleveland, Dongli Li

Sponsor: Healthcare Inovation CDT

Date: October 2012-October 2016

Lightweight Fan System Technology Development - SILOET II Project 2

This project focuses on the development of predictive numerical modelling capability for design of lightweight composite materials and systems for components of large aircraft gas turbine fan systems threatened by impact loading.  The research covers a spectrum of activities from experimental observation and quantification of relevant strain rate dependent deformation and failure mechanisms, through to development and validation of multi-scale modelling algorithms aimed at engineering of composite material architectures for optimised performance of engine components.  Topology optimisation based on the capability to simulate strain rate dependent behaviour of materials is an integral part of the materials engineering efforts.

People: Nik Petrinic, Robert Gerlach, Justus Hoffmann

Sponsor: TSB, Rolls-Royce

Date: October 2012-September 2016

Virtual Engine Design Systems - SILOET II Project 10

This project focuses on the coupling of isogeometric modelling with mesh-free discretisation in order to provide an all-NURBS platform for simulation of the response of solids to impact loading.

People: Nik Petrinic, Ettore Barbieri, David Hills, Dhrubajyoti Mukherjee

Sponsor: TSB, Rolls-Royce

Date: October 2012-September 2016

Multi-Scale Penetration Mechanics of Projectiles Through Granular Media Using Neutron and X-Rays

This project focuses on the development of multi-scale computational framework for simulation of impact on wet sand protection against ballistic penetrators.  The modelling efforts are accompanied by the research into in-situ and post-mortem diagnostics systems.

People: Nik Petrinic, Ettore Barbieri, Francesco De Cola

Sponsor: DTRA

Date: July 2012-June 2015

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


Date: October 2010-March 2015

Multi-scale methodology for enhancing damage tolerance of composite materials in submarine environment subject to underwater explosion and depth charge attack

This project focuses on development of experimental methodology for application of blast loading representative of that imposed by underwater explosion.  In addition, experimental methodology for characterisation of strain rate dependent behaviour of water saturated composited materials at several length scales for submarine applications is being developed.  Related computational multi-scale modelling methodology is being developed and validated against the results generated by the developed experimental methodology.

People: Nik Petrinic, Vito Tagarielli, Alan Cocks, Ettore Barbieri, Andreas Schiffer, Christian Kettenbeil

Sponsor: EPSRC, Dstl

Date: September 2009-March 2015

Numerical Modelling of Impact Phenomena

This project focuses on the integration of experimental and numerical methodologies in order to provide better understanding of physical phenomena excited by impact loading.  Particular efforts are directed towards such events occurring at elevated temperatures thus drawing special attention to phase changes in materials under consideration.

People: Nik Petrinic, Antonio Pellegrino, Petros Siegkas, Kalin Dragnevski

Sponsor: Rolls-Royce

Date: December 2010-November 2014

Numerical Modelling of Fragmentation, Penetration and Spallation

This project focuses on the development of algorithms for simulation of failure processes caused by impact loading.  Interaction of quasi-brittle and ductile materials is given a particular attention.

People: Nik Petrinic, Ettore Barbieri, Sascha Knell

Sponsor: Mitsubishi Heavy Industries

Date: March 2012-February 2014

Bubble Collapse by Shock Loading

This project focuses on the development of experimental methodology for shock loading of cavitation bubbles in viscous media.

People: Nik Petrinic, Yiannis Ventikos, Nick Hawker, Phillip Anderson

Sponsor: OXYNTIX

Date: February 2012-January 2014

Numerical modelling of shot peening process

This project focuses on the development of numerical algorithms and benchmarks required to provide validated methodology for simulation of shot-peening as manufacturing processing which relies upon impact loading to provide surface treatment required to reduce effect of cyclic loading upon components of advanced engineering systems such as aircraft gas turbine engines.

People: Nik Petrinic, Kovthaman Murugaratnam

Sponsor: EPSRC, Rolls-Royce

Date: May 2010-December 2013

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

Development of numerical modelling of failure in composite materials subjected to impact loading (SILOET 1)

This project focuses on the development of numerical algorithms for simulation of deformation in continuous fibre reinforced polymer matrix systems and related experimental support.  A combined continuum and discontinuity analysis methodology is being devised in order to simulate the effects of manufacturing induced flaws as well as those initiated during impact loading.  Algorithms for simulation of strain rate dependent behaviour hare being implemented in a multi-scale framework and are being validated against experiments at corresponding length scales.

People: Nik Petrinic, Jens Wiegand, Andreas Giebe

Sponsor: TSB, Rolls-Royce

Date: October 2009-September 2013

Investigation of rate dependent behaviour of titanium foams

The objective of this research is to develop both the experimental and numerical methodology for characterisation and predictive modelling of the response of sintered titanium foams to impact loading.  A range of different sintered Ti foams has been characterised under compressive loading at a range of strain rates. The sensitivity of foam strength to relative density and applied strain rate has been determined.  Modelling techniques have been developed to exploit the information obtained from X-ray scans of foams under consideration. This approach has been used to develop a virtual testing framework to complement the experiments in real laboratory.  The main objective is to explore experimentally and numerically the sensitivity of the foam response to geometry, porosity, applied strain rate, with the aim of developing homogenised constitutive models for the response of sintered Ti foams to impact loading at macroscopic length scale.

People: Nik Petrinic, Vito Tagarielli, Petros Siegkas

Sponsor: EPSRC, Rolls-Royce

Date: October 2007-March 2013

Impact Performance and Shock From Advanced Composites Technology (IPSoFACTo)
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, Prof. C. 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, Prof. C. R. Siviour, Robert Gerlach

Sponsor: Rolls-Royce

Date: September 2006-January 2010

Characterisation of composite materials and development of constitutive models in aid of lightweight hybrid fan systems (VITAL - enVIronmenTALly friendly engine)

The main objective of this project is to enable design of composite aeroengine components threatened by impact loading.  The experimental aspects of the work included initial selection of materials for aircraft gas turbine engine fan blade and containment applications as well as the full characterisation of selected materials.  Small-scale structural tests in controlled laboratory conditions have been carried out in order to provide data for validation of developed modelling tools.  Modelling aspects of the work have included evaluation of existing constitutive models and development of new algorithms for simulation of observed and quantified strain-rate dependent behaviour.

People: Nik Petrinic, Jens Wiegand

Sponsor: EU

Date: January 2005-September 2009

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

Self-consistent Modelling And Diffraction Study Of BCC And HCP Polycrystals

A coordinated experimental and modelling study of polycrystalline deformation and internal stress development in polycrystals of important structural materials will be carried out. Diffraction of beams of penetrating radiation (neutrons at ISIS and ILL, and synchrotron X-rays at the ESRF) on samples and components subjected to residual and live in-situ stresses will be used to collect detailed data on the internal stress evolution during straining. The data will be used to develop and validate elasto-plastic self-consistent (EPSC) models for these materials.

The systems targeted in the present study are ferritic steels (as representative of bcc structure) and titanium alloys (hcp structure). The approach will be used to characterise the evolution of intergranular stresses during monotonic and cyclic loading of polycrystalline samples, which will give new and improved insight into the influence exerted by the internal stresses on the performance and service life of structural materials.




Internal Stress Evaluation Using Multiple Peak Laboratory X-ray Diffraction Analysis

The main thrust of the project is to develop the application of multiple peak diffraction analysis to stress determination in polycrystals using modern laboratory X-ray equipment. While significant amount of effort over the last decade has been devoted to synchrotron X-ray and neutron work in this area, the distinct and important implications for laboratory X-ray analysis only begin to be systematically explored. In situ monotonic and cyclic loading devices will be used in order to develop novel methods allowing the determination of the sample's deformation history, and its residual strength.


Sponsor: Oxford, EPSRC


Strain Scanning For Engineering Applications Using Synchrotron X-ray Radiation

The advent of the third generation synchrotron source at the European Synchrotron Radiation Facility (ESRF) in Grenoble opened up new possibilities for efficient use of X-rays to map internal stresses in engineering components non-destructively. The photon flux furnished by the modern insertion devices exceed that available in the lab by the factor of 109, making measurements through over a centimetre of Al to the strain accuracy of 10-4 possible during seconds. Joint development projects are carried out in collaboration with Manchester Materials Science Centre (Prof. P. J. Withers) and University of Salford (Prof. P. J. Webster) . Several beamlines are involved at the ESRF (ID31 Powder Diffraction, ID11 Materials Science) and SRS (16.3 Materials) and development of hardware and software solutions for engineering purposes is carried out.


Sponsor: ESRF, EU TMR