6th ANNUAL CONFERENCE OF THE CDT IN ADVANCED COMPOSITES FOR INNOVATION AND SCIENCE POSTER BOOKLET Tuesday 11th April 2017 University of Bristol, Queen’s Building, University Walk, Bristol, BS8 1TR, UK Multifunctional Composites and Novel Microstructures Patient specific hip implants Behjat Ansari, Kate Robson Brown*, Richard Trask+, Mark Schenk, Nic Roberts *Department of Archaeology and Anthropology (University of Bristol), +Department of Mechanical Engineering (University of Bath) The feasibility of a bespoke revision hip implant solution is evaluated through the characterisation of the trabecular architecture of the acetabulum, the finite element analysis of a human innominate bone under typical load cases and the identification of a suitable substitute material, together with an appropriate processing method. Incentives Objectives Prevent 1.4 million More than Mesh F Bespoke osteolysis and procedures doubled in CT Scans generation O L solution promote A annually – 2000- and FEA TY osseointegration CI $5.84 billion 2010 I N UALFE High NA Growing demand, result of rise Structural Implant QLI durability FI in population age and obesity optimisation manufacture Trabecular characterisation Methodology • CT scanning of 4 hip bone specimens – focusing on acetabular region • 2D and 3D analyses of histomorphometric parameters 70 120 mes 60 of 100 CddlfcperoeiaTossmmc smcsk opocre nataandhtmnrs ieenn tio rdfueaaif eot cttwdtuioenh os tgetaa rh a pbkfaenep u) cdmel mul toasrmaosraplaree baenre er scdsdtcpeogeue e e lnataac hsweinmee ad lwyey ni t h 3D ANALYSIS% Bone volume for 3 voluof interest B.V/T.V (%)Fe12345m000000ale M11111111111ale Male - 2222222222222LEFT Male -333333333333 RIGHT 2D ANALYSIS% Bone area for 6 regions interest B.Ar/T.Ar(%) -22468000000 1 21210 3 11304 10550 6 edge, highlighted in e), b) thick cortical bone bordering the Notable findings cancellous region, c) smaller • Bone volume on average 14% lower in female specimen trabeculae, transversely connecting the larger, longitudinal • Varying degrees of anisotropy – variations in loading direction counterparts visible in d). Finite element analysis m Methodology u m xi • Loading for one- a m legged stance of s Contour plots principal stres • Pjjsooyiniimnnnttpes ahd –n yadssti as pt cuwrbooiicli ac Fjorienet bfoordcye sd,i awghrearme Kof ish ip Notable findings body weight minus weight of bearing leg, M is • Max principal stress 1.373 GPa at sacroiliac joint abductor muscle force and R is joint reaction force, • Compressive stress of 12 - 30 MPa around acetabulum edge – increasing with a and b moment tensile stress away from the edge arms of the forces K and M from the hip joint, Byrne • Varying body weight, abductor muscles force, joint reaction force and lever et al. (2010). arm ratio contribute to variations in load magnitude and stress distributions Future work Explore additive manufacturing methods such as FDM and EBM to create porous hydroxyapatite and tantalum scaffolds, and develop structural optimisation methods to aid implant design. Supported by www.bristol.ac.uk/composites Positioning and aligning CNTs by external magnetic field to assist localised epoxy cure Giampaolo Ariu, Ian Hamerton, Bhrami Jegatheeswaram Pillai, Dmitry Ivanov The investigation of effective through service on-platform repair technologies for propulsion systems is of interest for aerospace applications. The research focuses on the manipulation of nanofillers such as multi-walled carbon nanotubes (MWCNTs) through external magnetic fields for advanced curing. Methodology • Magnetic CNT positioning to create tailored CNT networks within composite. • Localised heating from CNTs for more controlled curing process. Schematic of composite inner structure for CNT magnetic alignment and translation. Magnetic positioning of the plated MWCNTs within epoxy resin Nickel-plated Magnetically CNTs blended driven CNT edge s ess with epoxy resin ng pCaNtTte mrna ncoipnufilramtioend c and exposed to di o n within resin. 10 mm Pr through-thickness Fi Alternative metals DC magnetic field tested showing Left: Ni-plated CNT positioning within epoxy PRIMETM20LV after exposition to B = 0.5 T until resin cobalt (Co) as (top view). Right: computerised tomography (CT) scan of PRIMETM 20LV + 2.5 wt.% Ni-plated MWCNTs (in red) under 0.5 T [1]. gelation. best plating. Magnetic positioning of Co-plated CNTs within composite: procedure Sample preparation NCF glass printed with 2.5 wt.% Co-plated CNT-filled epoxy (field/no field exposition), followed by resin infusion. A Sample characterisation B (c) C Co-CNT magnetic migration (A -> B -> C) from fracture surfaces through Co mapping (b) via SEM/EDX, together with mDSC/FT-IR (a) for Co-CNT effect on cure degree ((cid:302)). (a) Resin printer head used for the magnetic patch printing; (b) magnetic patch highlighting sample region and characterised fracture surfaces A, B, C; (c) machined sample region (c). Magnetic positioning of Co-plated CNTs within composite: results Cobalt distribution progression (magnetically driven CNT migration + filtration): Co-plated CNTs could localise and assist cure Increasing (cid:302) A B C Energy-dispersive X-ray (EDX) cobalt mapping (Co represented by yellow regions) at the fracture surface from Modulated Differential Scanning Calorimetry (mDSC) results showing effect location A to C. of Co-CNT distribution on cure kinetics. Future work [1] Ariu G., HamertonI., Ivanov D., Open Physics. (2016) 14:508-516 (DOI 10.1515/phys-2016-0057). Inductive cure of scarf Supported by samples bonded with Co-CNT- filled adhesive, followed by www.bristol.ac.uk/composites bond strength tensile testing. UV-responsive liquid crystal elastomers for room temperature shape change Laura Beckett, George Whittell, Valeska Ting, Richard Trask, Annela Seddon and Ian Manners Liquid crystal elastomers (LCEs) are capable of programmed shape change by switching between the nematic mesophase and the fully disordered isotropic state. By introducing a UV-responsive azo group to the mesogen, disruption of the nematic phase can occur reversibly at room temperature; a process which has been exploited for soft actuators. This work focuses on developing thermoplastic LCEs with the aim of using extrusion to obtain well-aligned, UV-responsive fibres. Polymer Synthesis and Characterisation A synthetic route to the DSC confirms thermal functional polymer has been xSiOySiOzSiOSizOSiy x transitions in desired range: developed with the following O OS OS S + N OO OC4H9 advantages: OH OH OH H9C4O NHO =LC W/g) -0.1 PTgM–VS2 0M°idCblock TNiesom–a1tic2-0Is°oCtropic • High yield – 85%. DichlorDoCmCethane Room48tehmopuerrsature ow ( -0.2 transition DMAP Fl • Mild reaction conditions. eat H -0.3 • Ability to accommodate a SiOSiOSiOSiOSi x y z z y x -0.4 variety of polymer S S S -50 0 50 100 150 Temperature (°C) bgraocukpbso.nes/mesogenic LOCO OO OOLC tAebmopvee rtahtiusr eT g–at room Troraonms ittieomn poecrcautursre a t N O polymer is soft and with UV irradiation H9C4O N OC4H9 deformable O UV-Induced Shape Change Towards Responsive Fibres • Stretching polymer film in isotropic • Aim to use shear forces encountered state aligns mesogens to enable during extrusion to form a well-aligned shape change. liquid crystal monodomain. • Manually stretched thin film held Isotropic polymer in under tension (25.7 kPa stress) - contracts on irradiation with UV light: Anisotropic, responsive fibre out 0.020n n n O O O V- V- V- UV-On Force (Newtons) 000...000011505U UV-O U UV-O U UV-O Fmloewso tghernosugash fsocrrceewd etxhtrrouudgehr naolizgznlse Polymer Film 0.000 ff ff ff • Compare UV response with manually 0 60 120 180 240 300 360 420 UV-Off Time (seconds) aligned film. • Visible light returns polymer to its • Investigate effect of fibre diameter on original state – contraction stops. response. Supported by www.bristol.ac.uk/composites Inverse opals for active colour tuning devices Diego Bracho, Ian Hamerton, Richard Trask, Annela Seddon Photonic crystals are periodic ordered microstructures, built from dielectric materials, with a periodicity in the scale of visible light wavelength (~200-700 nm). Through rational design and smart tuning of the PC periodicity it is possible to tailor the colour exhibited by these materials. The main objective of this work is to design and assemble photonic crystal structures based on colloidal self assembly and silica sol-gel chemistry for active colour display devices. Results (a) Polymer opals and silica inverse opals were prepared by colloidal self-assembly and sol- gel chemistry. The resulting species exhibit angle-dependant colouration characteristic of 555mm photonic structures (Fig. 1a). These exhibit a (b) (c) face-centered cubic (FCC) structure, with the (111) plane oriented at the surface of the structure (Fig. 1b,c). The exhibited colour can be tuned by altering 22(cid:645)(cid:645)(cid:645)(cid:645)m 22(cid:645)(cid:645)(cid:645)(cid:645)(cid:645)(cid:645)(cid:645)(cid:645)m one or more physical parameters of the Figure1: system, such as lattice spacing (Fig. 2), a)PhotographofSiO inverseopalcoatedwithsilver((cid:660)=1μm) 2 symmetry, induction of defects, and refractive b)SEMimageofapolymerdirectopal((cid:660)=240nm) index contrast (Fig. 3). c)SEMimageofSiO inverseopal((cid:660)=500nm) 2 1000 nm 500 nm 310 nm 240 nm Glass substrate Figure3:DiffuseUV-visspectraofSiO inverseopals((cid:660)=240nm) Figure 2: Diffuse UV-vis spectra of PS opals ((cid:660)=240, 2 coatedwith15nmAginair(a),andinfilledwithethanol(b).Inset 310,500and1000nm) showsphotographsofthedevicedisplayingcolourchange Conclusions and Future Work • Direct and inverse opals of different pore sizes were fabricated using a vertical deposition method in a single-step co-assembly of polystyrene colloids in a silica precursor solution. • Tunability of the photonic bandgap within the visible spectrum is interesting for potential applications in photonics and optics, such as colour display devices, active camouflage, sensors, etc. Future work will include the integration of smart materials, aiming for complete tunability within the visible spectrum. Supported by www.bristol.ac.uk/composites Surface modification of composite material for space application—a baseline Yanjun He, Ian Hamerton, Mark Schenk, and Alex Brinkmeyer To improve the durability of composites materials for space applications, a surface modification ‘Photosil’ technique is considered. This technique is a surface modification treatment which improves the resistance to atomic oxygen and UV radiation by silylation of the surface of the composite material. For space deployable structures, where flexural properties are of great importance, tests are performed to ensure the modification does not affect the flexural properties of the material. In this work, a three-point bend and bend radius test, together with acoustic energy measurements, were performed on four types of untreated samples. Together these form a baseline for subsequent comparison to Photosil-treated samples. Test methods • A three point bend according to ASTM D790-15 is applied to the samples. After the first test, the samples are bent around a rigid cylinder 10 times to simulate repeated stowage damage. An acoustic sensor is used to record the energy during the bends to detect fibre damage and failure. The three-point bend test is conducted again after simulated stowage. • Laminates tested (all laminates contain toughened epoxy): - LAM01: Carbon PW 94gsm -LAM02: Carbon PW 61gsm - LAM03: Kevlar PW 60gsm - LAM04: Hybrid Kevlar 60gsm/Carbon 61 gsm Bend radius test set-up Results Acoustic Energy (AE) and amplitude vs. bend number for Flexural stiffness before and after bend for (a) LAM01, (b) LAM01 (rescaled), (c) LAM02, (d) LAM03 and each sample (e) LAM04 Conclusions and future work • Fibre failure occurred the first bend of LAM01, meaning that this laminate is not suitable for this stowage application. LAM01 and LAM03 show more matrix cracking signs compared to LAM02 and LAM04, with the Kevlar laminate undergoing significant damage after 10 cycles of stowage. • The results from the acoustic sensor showed consistent results with three-point bend. • Future work consists of optimising the set-up of bend radius test to improve the baseline, and of testing samples after Photosil treatment and VUV/ATOX exposure. Supported by www.bristol.ac.uk/composites Creating folds: Origami inspired morphing Manu Mulakkal, Richard Trask, George Whittell, Ian Manners and Annela Seddon Folding is a key process at the heart of morphing or transformations that occur in nature. Whether it’s the formation of proteins from polypeptide sequences or vast mountain ranges through the movement of tectonic plates; folding is ubiquitous in nature. A methodology for creating folds on fibrous substrates, such as paper, utilising the forces developed within hydrogels during drying is presented. This methodology is not just limited to folds but curves and sophisticated pop-up structures can also be realised through pertinent design. The shapes formed can revert back to the flat configuration using the stimuli of water. This methodology and design parameters are envisaged to better inform the design and fabrication of stimuli-responsive fibrous substrates. Principle of actuation: shrinking driven Shrinking of hydrogel due to loss of water would create a positive curve on paper due to strain mismatch driving the open regions close to each other Independent Coupled free ends Hydrogel Paper De-hydrated gel 5 mm 10 mm 15 mm 180 °C for 5 min Flat Pop-up 30mm 30mm The resulting fold angle depends on: the amount of gel-forming polymer, its spread, stiffness of paper (i.e grammage) and open area that needs to be folded Examples of some Origami inspired transformations Rectangle to helix Concentric circles to saddle-like shape Hydrogel lines at prescribed angle and spacing on paper Scale bar: 25 mm Construction 45°:(spacing 10 mm) 45°(10 mm) 30°(5 mm) 45°(5 mm) 1-annular paper cut (bottom) 2-gel 1 2 3 1 3-annular paper cut(top) 30°: (spacing 5mm) Front view Side view 3 1 1 45°:(spacing 5 mm) Scale bar: 10 mm Supported by www.bristol.ac.uk/composites Additive manufaFclowt/fiultratrioning of multi-functional and patterned GFRP composites Arjun Radhakrishnan+, David Stanier+, Ian Gent+, Ian Hamerton+, Milo Shaffer*, Dmitry S Ivanov+ +University of Bristol, *Imperial College London Conventional liquid composite moulding processes are hindered by high viscosity when using multiwall carbon nanotubes (MWCNT) enhanced resin. To overcome these limitations and allow the processing of patterned multi-functional GFRP, a combination of two novel approaches are explored in this work : a) use of heterogeneous solution (powder- liquid) and b) Liquid resin print. This process allows for localised enhancement of mechanical and functional properties of the composites. PROCESSING OF PATTERNED COMPOSITES PATCH MORPHOLOGY Step 1: Heterogeneous solution • Filtering of the powder through the fabric from the site of the injection leads to natural grading of the The novel powder mmaattrriixxppaattcchh.. helps improve the processability of solution with higher CNT loadings by Solution = encapsulating them 15 wt.% CNT powder + liquid epoxy within solid epoxy. • Distribution of the particles can be controlled via processparameters. • Electrical conductivity maps across the matrix patch Step 2: Liquid resin printing varies withconsolidation schemes. • The solution is injected into a preform using a • Different patch 3D printer with morphologies are modified head to form achievable a matrixpatch. through consolidation • Higher loadings of parameters. upto 3.5 wt% CNTs are possible when matrix is applied MECHANICAL PROPERTIES locally. • Open hole SSttrreessss,, MMPPaa tensile test increase of Stepp 3: Consolidation (hot press) 17% and 24% of strain-to- • Consolidation pressure is failure and applied at a predefined strength Strain, % degreeof cure. respectively. • Patch morphology is controlled by injection and MOVING FORWARD consolidation parameters. • Mechanical modelling of multi-matrix composites. • Investigating: a. Influence of the multi-matrix interface Step 4: Resin infusion of patched preform on tailoring the mechanical performance. Preform with functionalised b. Optimisation of patch architecture. cured patch is infused using • Assess the feasibility for application in: conventional processes to a. Reinforcing stress concentration create a patterned multi- features like joints. matrix composite. b. Vibrational damping. Supported by www.bristol.ac.uk/composites 3D mesostructures via compressive buckling and potential applications Rujie Sun, Xinge Yu, Xin Ning, Jonathan Rossiter, Fabrizio Scarpa Mechanical assembly of 3d mesostructures with programmed configurations are explored. This method could transfer a variety of advanced materials from 2d precursors into mechanically tunable 3d architectures with broad geometric diversity. Such structures show great potential in areas, including microscale rheology measurement, soft robotics, energy harvesting, and cell mechanics. Experimental Demonstrations (cid:41)(cid:76)(cid:74)(cid:17)(cid:3)(cid:20)(cid:17)(cid:3)(cid:57)(cid:68)(cid:85)(cid:76)(cid:82)(cid:88)(cid:86)(cid:3)(cid:22)(cid:71)(cid:3)(cid:80)(cid:72)(cid:86)(cid:82)(cid:86)(cid:87)(cid:85)(cid:88)(cid:70)(cid:87)(cid:88)(cid:85)(cid:72)(cid:86)(cid:15)(cid:3)(cid:86)(cid:70)(cid:68)(cid:79)(cid:72)(cid:3)(cid:69)(cid:68)(cid:85)(cid:3)(cid:24)(cid:19)(cid:19)(cid:3)(cid:459)(cid:80) Potential Applications Bonding site SU8 Actuation Fig. 2. Soft robotics Fig. 3. Microscale rheology measurement Supported by www.bristol.ac.uk/composites