1. Achieving Vertically-integrated Carbon-fibre Reinforcement Design and Manufacture Demonstrators for Structural Manufacturing and Construction 3-D Composites Parminder Singh Kang 1*, Yong Sun 1, Chris Silva 2 and Alistair Duffy 1 1 Faculty of Technology, De Montfort University, Leicester, UK 2 M Wright and Sons Limited, Quorn Mills, Quorn, Loughborough, UK *De Montfort University, Faculty of Technology, The Gateway, Leicester, LE1 9BH, UK E-mail: pkang@dmu.ac.ukpkang@dmu.ac.uk 1. Introduction Composites are widely used engineering applications. However a new range of composites called 3-D woven are not widely used due to the lack of purposely designed analysis tools. The AVISC project developed designer equipment to evolve 3D woven composites. These woven composites, have binder yarns used to stitch the layers of fabric together; essentially a three dimensionally woven material with warp, weft and binder. In this research emphasis has been put on the number of filaments which make each binder yarn. Two different sizes have been used; 3000 (3K) and 6000 (6K) respectively. 2. Aims and Objectives The main objective of this project is to achieve robust vertically-integrated design and manufacture for structural 3-D Carbon Fibre Reinforced Composites (CFRCs) for the high-value manufacturing sector and woven 3-D reinforcements for concrete and composites to be used in the construction sector. Key innovations are the creation of mechanical-property knowledge (MPK) through the correlation of theoretical simulations and test results and the development of algorithms and software to relate 3-D solid CAD models to weaving CAD enabling composites and reinforcement pre-forms to match user requirements. 3. Research Method M Wright and Sons (MWS) have designed, commissioned and developed a unique CNC-controlled loom, with weaving CADCAM, capable of weaving 3-D solid carbon fibre reinforcement pre-form (CFRP) sections, whilst several 3-D solid CAD and finite element packages are currently available. The MPK base is created as a result of the project’s iterative weaving, moulding, testing and analysis stages. The application of data mining techniques, correlation analysis and neural networks are used to interrogate the developed, practical MPK base, so that so that any 3-D structural composite CAD design that is in the realms of practical manufacture can create a weaving pattern in the weaving CAD system through novel software, algorithms and communications interfaces. The resultant CFRP pre-form should give a right-first-time prototype when moulded into a composite to give the desired properties of the original CAD design. 4. Manufacturing Technology Currently composite parts are made by stacking multiple layers of fabrics to form the desired shapes and dimensions. However, there are many significant issues with this manufacturing process:  it suffers from potential layer separation  it can involve sequential curing  it is labour intensive or involves complex automatic equipment  it can produce excess waste and may be difficult to obtain repeatability The solution offered by the 3 D weaving composites is the capability to offer a preformed shape to the required dimensions. This offers the possibility to reduce the manufacturing process from fabric to composites considerably since there is no need to layup. Manufacturing tests conducted at MWS suggested a fabric preparation timing reduced by a factor of 6 when using a preform against a normal layup. The layup process requires trimming of the each individual layup to fit within the fabric stack. This operation is time consuming and waste material. The infusion timing for 3D woven fabric is also quicker than a normal layup. This is due to the binder yarn running through the thickness. This allows for the resin to reach the middle of the fabric quicker. MWS in house testing revealed that for the same fabric areal weight the timing required to infuse a 3D woven where half the one required to infuse a normal layup. At the current state of art the 3D weaving capability developed at M Wright & Sons Ltd allows for “T,I,L,U” shaped carbon preform to be produced. 5. Results The new 3-D woven carbon composites were tested under various loading conditions, following the procedures in the appropriate ISO standards. These tests include tensile test, compression test, flexural test, interlaminar shear strength test and compression- after-impact test. The results show that, as compared to the industrial standard carbon composite Panel 50, the 3-D woven composites possess higher compressive strength, similar tensile and flexural strength and do not experience interlaminar shear failure. Most importantly, the 3-D woven composites possess much higher compression-after-impact strength and thus are more resistant to impact damage. It is also found that the mechanical properties of the 3-D composites are influenced by binder yarn size. For further details, please consult the AVISC Web Tool at: http://www.avisc.orghttp://www.avisc.org 6. Key Findings One of the key findings of this research is the significantly improved compression-after-impact strength over existing industrial standards, which could enhance the life span and safety performance for products made out of advanced 3-D woven materials. The performances of 3-D woven materials are given in the graphs below: Tensile StrainMean Tensile Strength and Modulus Mean Compressive Strength and Modulus Mean Compressive-After-Impact Mean Flexural Strength and Modulus 7. Potential Industrial Applications The improved performance of all 3-D weaving composites using AVISC means that they can be optimised for specific applications, and can be better designed for specific crash test criteria standards as required. As such, they have tremendous scope in their application to high value manufacturing industries, for instance the wind energy, aerospace, automotive, construction and medical sectors, etc. Aerospace Industry ; all future aircraft have strict economic efficiency criteria to adhere to, which means that many conventional materials will have to be replaced by composites. The Airbus the A350 XWB will be the first airbus to be over 50% composites which is optimistic. Wind Energy Sector ; the use of AVISC to design and manufacture lighter and comparably cheaper components would mean that competitive energy prices through wind energy would be possible. The price of wind energy depends upon the institutional setting in which wind energy is delivered. This means that wind energy costs should be measured in terms of: production, operation and maintenance costs for running a wind farm, the price per kWh that wind energy can be sold at. This approach has the advantage over conventional reliance upon oil and gas, in that the effective currency is the unit price of energy itself. Automotive Industry ; there is a current lack of standardisation of sizing and surface treatment technologies associated with carbon fibre technologies. In addition, the existing carbon fibre industry is not fully equipped to support large scale vehicle manufacture. Because AVISC is based upon unique MPK data standardisation of sizing and surface treatment technologies need not be an issue. Components would be designed and manufactured to fulfil a specific set of criteria, rather than adapting existing CFRPs to fit those criteria. Construction Industry ; the opportunity to replace steel as reinforcement for concrete is worth £100billion in terms of global demand. There are also a considerable number of existing reinforced structures which do not meet current design standards due to inadequate design and/or construction or which need structural upgrading to meet new seismic design requirements. Given CFRPs’ inherent properties, such as high tensile strength, good fatigue and corrosion resistance and ease of use, AVICS is a particularly attractive solution for the construction industry. Medicine ; there are a large number of potential applications for AVISC. One of the most promising areas is in the surgical application of Fracture Fixation Plates (FFPs) in the treatment of bone fractures. Accordingly, a bone fracture can be assisted by screwing a FFP across the junction of a bone fracture. However, this can interfere with normal bone physiology by stress sealing of the bone beneath the plates. Density of living bone is directly proportional to the stress applied. Therefore, AVISC allows for the design of an FFP with a similar elastic modulus to bone, which offers a significant advantage over metal FFPs. Sports Goods ; the shaft of golf clubs but also bicycle frames, forks, handlebars, seat posts and crank arms are increasingly made from carbon fibre composites. Also, there are many possible markets for CFRCs where stiffness and low weight is required, such as in musical instruments. In addition, due to the fire-resistance of polymers and thermo-set composites, carbon fibre composites are increasingly being applied to situations where heat has been a problem in the past. The potential markets for AVISC are therefore only limited by the lack of MPK for a given application. 8. Acknowledgements The authors would like to thank Technology Strategy Board (Project No: 101147 and TSB Reference: 13451-87159) and De Montfort University for funding this research. Generate 3-D Solid CAD model Undertake Finite Element Analysis (FEA) Use Cosmos FEA outputs to refine CAD model Use Scotcad CAD/CAM software to generate Loom CNC program Weave CFR Preform using CNC program RTM Mould CFR Component Test Component and Output results to FEA Undertake Finite Element Analysis (FEA)