Structures

Research Theme

Stephen Hallett

The Structures Academic Team2

Our research into the mechanical performance of

composites encompasses novel numerical methods, novel structural

configurations, advanced analysis techniques, multi-functionality and

data rich experimentation.

Stephen HallettProfessor in Composite Structures

Paul WeaverProfessor of Lightweight Structures

Mark SchenkLecturer in Aerospace

Engineering

Alberto PirreraSenior Lecturer in

Composite Structures

Luiz KawashitaSenior Lecturer in Composite

Mechanics

Ben WoodsSenior Lecturer in

Aerospace Structures

Michael WisnomProfessor of Aerospace Structures

Giuliano AllegriReader in Composite Structures

Terence MacquartLecturer in Aeroelasticity

Janice BartonProfessor in Experimental Mechanics

Eleni ToumpanakiLecturer in Civil Engineering

New Academic - Dr Eleni ToumpanakiBackground• PhD in Civil Engineering (composites and concrete)

- University of Cambridge

• Structural Engineer at Foster + Partners

• Research Associate (timber engineering) - University of Cambridge

• Lecturer in Civil Engineering in Bristol since November 2019

Research Interests

• Composites: (FRPs), timber, concrete

• Bond performance, durability, resilience, sustainability

• Experimental methods (e.g. DIC)

• Analytical solutions and numerical analysis

• Nano- to building scale

New EPSRC Early Career Fellowship4

• Awarded to Dr. Benjamin Woods

• AdAPTS: Adaptive Aerostructures for Power and

Transportation Sustainability

• £1.1M budget, 5 year duration

• Will develop compliance-based morphing

technologies and powerful new analysis tools

• Partnering with Airbus, Leonardo, and Vestas to

develop more efficient Aircraft and Wind Turbines

RAEng Senior Research Fellowship 5

• Started October 1st – duration of 5 years

• Fatigue testing combined with theoretical developments

and numerical implementation at each scale

• Role of environmental effects (temperature & moisture)

• Delivery of accelerated fatigue testing methodologies for

certification purposes

• In-service diagnostics and prognostics (digital twins)

“Physically Based Modelling of Fatigue in Composites”

• Awarded to Giuliano Allegri

Other Awards/Highlights6

• Janice Barton - invited to present the US Society for Experimental

Mechanics’ 2020 William M. Murray Lecture for her pioneering

contribution to Thermoelastic Stress Analysis (TSA)

• David Brigido – Won University of Bristol’s Three Minute Thesis

(3MT) competition, and the People’s choice award – “Coffee, Fish,

and Aeroplanes”

• David Brigido – Also won the Jefferson Goblet Student Paper

Award at the 2020 AIAA SciTech conference

• Andres Rivero Bracho - Won the Dyson Sustainability Award at

STEM for Britain for his work on the Fish Bone Active Camber

(FishBAC) device

• Michael Wisnom, together with Federico Paris (Universidad de

Sevilla), led an on-line workshop on

"How do we define and measure strength of a composite?”

• Panel of 12 international experts to discuss and debate the topic

• Over 100 people joined on-line

• You can watch the

presentations and discussion

on the BCI YouTube Channel

On-line Workshop7

Lab Update8

• Laboratory work impacted by Covid 19 pandemic

• Closed in March 2020

• Lockdown time used effectively to improve

lab operating procedures

• Reopened in June 2020 with new

safety protocols and reduced capacity

• At start of November (before lockdown 2) all

requests to access lab being accommodated

• Even had time to procure, install and commission new equipment

• Instron Elecropuls E10000

• Telops MK3 Fast Infra-red camera (100 kHz)

Composites UTC9

• Large and very active programme• 8 BCI academics, 9 RAs, 12 PhD students,

3 EngD research engineers

• Impact case study submitted for UK Universities

REF2021 exercise• Cohesive Zone Interface elements for delamination

modelling

• Currently TRL8 – used in production version of LS-Dyna

for component design

• Direct Insertion method of manufacturing Through-

thickness Reinforced composite laminates

• Custom designed robotic cell installed at the Filton

Composite Technology fan blade pre-production facility

UTC Technical Highlight10

• Next generation CZM now being developed

• Designed to model delamination with large meshes

• Rotational degrees of freedom added to nodes to better capture crack tip stress field

• CZM Elements inserted “on-the-fly” for element splitting

• Demonstrated to work on simple fracture toughness tests

• Successfully applied to complex gelatin impact tests

* Selveraj et al – submitted to Composites Science and Technology

Wind Blade Research Hub11

• Led by Paul Weaver and Alberto Pirrera

• 17 UoB researchers and academics

• Unique in-house wind turbine aeroelastic

analysis and tailoring capabilities, with specific

focus on composite optimisation

• EngD student, Robbie Herring, involved in the

work of The Climate Change Committee

producing the Progress Report to Parliament

on Reducing UK Emissions

• Close four-way network comprising the UoB,

ORE Catapult, Vestas, the NCC and other universities

Blade Hub Technical Highlight12

• Collaborations with

• Imperial College on novel blade topologies for

additive manufacturing

• Limerick and Strathclyde on health monitoring

and recycling methods for wind turbine blades and

their application to wind farm level

• NCC and ORE Catapult to

• Identify the potential for advanced composites for the next generation floating turbines

• Develop blade concept and baselines for 20MW wind turbines

Composite tailoredstructural parameterisation

13

Integration of multi-scale modelling and high-

fidelity data-rich testing on structural scale via

Bayesian learning and ‘Design of Experiments’

• Led by Ole Thomsen

• 10 PDRA hired - 6 in Structures Theme of BCI

• 4 Research Challenges:Multi-scale

Performance

Modelling

Data-rich High-

fidelity Structures

Characterisation

Features and

Damage

Characterisation

Integration and Validation

of Methodology

“CerTest” Certification for Design: Reshaping the Testing Pyramid

CerTest Technical Highlight14

• Composite failure is usually initiated by small scale events

• Best modelled by high fidelity solid models

• Large aerospace structures require a homogenized model

• Usually shell element models.

• We are developing multi-scale modelling techniques for accurate damage prediction at structural scale

• Combining the two scales in a nonlinear analysis with shell and solid element models.

Step 1: Sample strains and curvatures

Shell element

High-fidelity solid model

Global structure

**Step 3: Boundary conditions for scale

transition

Step 4: Return homogenised constitutive

tangents and stresses

Step 2: Build solid model

Summary and Outlook15

• 33 Staff Researchers and 30 PhD students

• World-class research and activities, ranging from blue-sky to

engineering applications

• See poster sessions for more technical details

• Delivering innovative solutions and technology for our

industrial partners

• Opportunities for new projects and technology transfer

Posters16

• Giuliano Allegri - Physically Based Modelling of Fatigue in Composites

• Ganapathi Ammasai Sengodan - A visco-elastic cohesive zone model for rate and

temperature dependent interlaminar fracture of composites

• Xiaoyang Sun - Predicting Trans-laminar Fracture Using VCCT and In-situ CT Scans

• Karthik Ram Ramakrishnan - Full field imaging of composite structures combining

DIC and IR thermography

• Hernaldo Mendoza Nava - Sound production through elastic instabilities in the

aeroelastic tymbals of ermine moths

• Reece Lincoln - Imperfection-Insensitive Continuous Tow-Sheared Cylinders

• Keyao Song - Form-Finding of Tessellated Tensegrity Structure

• Andres Rivero - Flexible Airplanes? Achieving higher fuel efficiency by continuously

adapting wing geometry

• Calum McInnes - Improving the dynamic performance of launch vehicle structures

• Xun Wu - Compressive failure strain of unidirectional carbon fibre composites from

bending tests

• Samuel Scott - Optimal Aeroelastic Tailoring of Wind Turbines

• Alex Moss - Topological Optimization of Large, Additively

Manufactured Composite Structures with a Graded Lattice Core

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stephen.hallett@bristol.ac.uk