Local Approaches in Composites Dmitry S. Ivanov Bristol Composites - - PowerPoint PPT Presentation

Local Approaches in Composites

Dmitry S. Ivanov

Bristol Composites Institute – National Composites Centre conference 2019

21/11/2019

To discuss

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• Locality for forming
• Locality for functionality
• Locality for composite properties
• Locality of precursor testing

Local tuning properties of the composite structures or composite precursors for efficiency and cost

Locality for forming

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Mark Turk, Adam Thompson, Jonathan Belnoue, Stephen Hallett, Dmitry Ivanov

• Complex shape (taper, convex/concave corners) – drapable but not formable
• Solution = patches of liquid thermally-conditioned fast-curing resin:
• No interference with fibre architecture
• Viscosity of the patches – can be tuned by staging to advantageous degree of cure

Non-optimised patch

Turk M.A., Vermes B., Thompson A.J., Belnoue J.P.-H., Hallett S.R., Ivanov D.S. Mitigating forming defects by local modification of dry preforms, Compos A 128 (2020)

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Locality for forming

Mark Turk, Adam Thompson, Jonathan Belnoue, Stephen Hallett, Dmitry Ivanov

• Patch placement – complex multi-parameter optimisation -> patch properties, size,

position, orientation – all play role.

• Orientation of narrow “stripe patches” = allows to strike a right balance between shear

rigidity and bending stiffness of modified fabric

• Forming made possible without blank holders, springs, or additional arrangements

Turk M.A., Vermes B., Thompson A.J., Belnoue J.P.-H., Hallett S.R., Ivanov D.S. Mitigating forming defects by local modification of dry preforms, Compos A 128 (2020)

Patch strips Critical corner A B C D E

Locality for multi-matrix composites

5 Segmentation of non-formable parts Optimisation through simulation Depositing non- formable elements Forming and infusion Integrating non-formable:

• Functional

elements

• Reparable

patches

• Reformable

edges

• Toughening

crack- stoppers

Mark Turk, Michael Elkington, David Anthony, Emile Greenhalgh, Dmitry Ivanov

Locality for mechanical performance

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Stanier D., Radhakrishnan A., Gent I., Roy S.S., Hamerton I., Potluri P., Scarpa F., Shaffer M., Ivanov D.S. Matrix- graded and fibre-steered composites to tackle stress concentrations, Compos Struct 207 (2019) 72-80.

University of Machester, Imperial College London, University of Bristol

• Patch placement – local tailoring of

material properties through high volume fraction of additives

• Local fibre steering in braiding process

Locality for mechanical performance

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Hengli Cao, Laveena Thadhani, Ric Sun, Luiz Kawashita, Dmitry Ivanov

¼ of sample Braiding simulations

• pen hole

Stress analysis

patch

• Analysis of locally varying fibrous and matrix architectures
• Combined numerical simulation of process and mechanical modelling of the resultant

materials with embedded elements

Locality for mechanical performance

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• Sample fully infused with “patch material” is not as

effective as when locally introduced

• Patch shape matters – optimum shape is complex
• Steering damage away from the critical location can

be beneficial

• Patch material/configuration can change the failure

mode

Hengli Cao, Arjun Radhakrishnan, Dmitry Ivanov Change of failure mechanisms in patched samples Redesigning stress distribution around

• pen hole

Diverting damage accumulation from critical locations

Patch deposition

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Path morphology for various processing conditions Rheological characterisation of fast curing functionalised resins Consolidation analysis of patches with various degree of cure (DOC)

Patch printing = out-of vacuum bag process. Patch quality is found to be

• tunable. Matching consolidation parameters to resin chemorheology

Arjun Radhakrishnan, Ian Hamerton, Dmitry Ivanov

Locality of testing for precursors

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• The systems is set to recognise

the flow/deformation modes by its characteristic signatures

Anatoly Koptelov, Jonathan Belnoue, Stephen Hallett, Dmitry Ivanov

Output: flow

mode, material properties

Autonomous tester

real-time data processing

Library of models Testing machine

Shear flow Percolation flow Tow scale Fibre-scale Patch-scale Zero friction No slip

Process

• ptimisation
• Proof-of-concept in virtual

space – right flow mode is recognised automatically

Acknowledgements

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• EPSRC Future Composites Manufacturing

Hub CIMComp, Core Project “Manufacturing for structural applications of multifunctional composites”

• EPSRC Platform Grant “SIMulation of new

manufacturing PROcesses for Composite Structures” (SIMPROCS)