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Details of Grant 

EPSRC Reference: EP/I021043/2
Title: Micro-mechanical modelling techniques for forming texture, non-proportionality and failure in auto materials
Principal Investigator: Dunne, Professor FP
Other Investigators:
Wilkinson, Professor AJ Cocks, Professor AC Todd, Professor RI
Researcher Co-Investigators:
Project Partners:
BMW
Department: Materials
Organisation: Imperial College London
Scheme: Standard Research
Starts: 01 July 2012 Ends: 31 March 2015 Value (£): 384,427
EPSRC Research Topic Classifications:
Eng. Dynamics & Tribology Materials Characterisation
Materials Processing Materials testing & eng.
EPSRC Industrial Sector Classifications:
Aerospace, Defence and Marine Manufacturing
Transport Systems and Vehicles
Related Grants:
Panel History:  
Summary on Grant Application Form
A well-defined programme of biaxial forming tests will be carried out by our collaborators at BMW in which the steel microstructures, both before and after straining, are fully characterised using optical and scanning electron (with EBSD) microscopy in order to quantify micro- and macro-level texture and its evolution and to provide the material morphology and crystallography as input to the computational work. Additionally, TEM and x-ray/neutron diffraction work will be carried out in order to investigate dislocation structures established and whether particular forms develop during non-proportional straining. The non-proportional 'Nakajima' tests will be carried out on two materials; namely, a conventional 'forming grade' steel and a high strength steel for which currently, formability is a problem. 3D representative volume elements, RVEs, with appropriate periodic boundary conditions will enable texture development, non-proportionality of straining and localisation and necking to be studied and direct comparisons may be made with the experimental data. The key features of the crystal slip model - the form of the evolution of statistically stored dislocations, the development of geometrically necessary dislocations due to plastic strain gradients, and the establishment of dislocation structures - can be refined by use of the TEM and the experimental localisation results. Once established and validated, the RVE technique becomes powerful and enables parametric studies of the effects of non-proportionality to be carried out in a way that is simply impossible with an equivalent experimental programme.The computational models will naturally take into account the full range of length scales that occur in this problem: at the dislocation and grain levels as well as length scales related to the formation of the localized band of deformation. The resulting simulations will be used to guide the development of simplified models based on the Marciniak and Kuczynski approach. This will be undertaken at a number of different levels to aid the development of tools that can be readily used within an industrial environment. Also the full range of simulations will be used to aid the development of design rules which account for non-proportional loading and which can be used to guide the initial development of a processing route.
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Organisation Website: http://www.imperial.ac.uk