National Composites Center

Bristol, United Kingdom

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Bristol, United Kingdom
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Pickard L.R.,University of Bristol | Partridge I.K.,University of Bristol | Shakspeare P.,National Composites Center
ECCM 2016 - Proceeding of the 17th European Conference on Composite Materials | Year: 2016

In the composites sector, where fast growth is forecast to increase even further, use of in-process monitoring to understand and improve manufacturing processes and the resulting parts has huge potential. Despite having been used in academia for some time, such technologies are not popular in industry. The reasons for this are many and varied, however it is notable that academia and industry communicate their knowledge, both within and without their organisations, very differently. This paper explores these differences in the composites community and reports on the development of an industry-targeted resource for the case of dielectric cure monitoring, designed to enable industrial uptake of this technology and to provide a template for others. © 2016, European Conference on Composite Materials, ECCM. All rights reserved.


Kaddour A.S.,QinetiQ | Hinton M.J.,National Composites Center | Smith P.A.,University of Surrey | Li S.,University of Nottingham
Journal of Composite Materials | Year: 2013

The authors have recently completed two world-wide failure exercises, which dealt with benchmarking recognised failure criteria under two-dimensional and three-dimensional loadings, respectively. A new phase, called the 'third world-wide failure exercise' is currently underway to fill some of the major gaps identified in the previous activities. The third world-wide failure exercise is concerned with highlighting the degree of maturity of the current capabilities of 12 internationally recognised methods for modelling various aspects of damage in composite materials. Such problems include matrix cracks due to thermal and mechanical loads; delamination; ply constraint and stacking sequence effects; loading and unloading phenomena; failure due to stress gradients (in particular the hole size effect). The topics addressed within the third world-wide failure exercise represent an extremely important and crucial area for advanced modelling and virtual testing of composites. The third world-wide failure exercise runs in two stages (1) Part A which is devoted to providing full details and a comparison between the 12 theories together with their 'blind' predictions, made by their originators, for a challenging set of test problems and (2) Part B which is concerned with comparing the theoretical predictions with experimental results and assessing the accuracy and maturity of the methods. This paper provides details of the background to third world-wide failure exercise, the process of completing Part A and a summary of key conclusions. © The Author(s) 2013.


Kaddour A.S.,QinetiQ | Hinton M.J.,National Composites Center | Smith P.A.,University of Surrey | Li S.,University of Nottingham
Journal of Composite Materials | Year: 2013

This paper gives details of the input data and a full description of a set of 13 test cases provided to the participants of the third world-wide failure exercise for use in their theoretical models. World-wide failure exercise is aimed at benchmarking leading methods, capable of predicting initiation and progression matrix cracking and damage and failure in composites. The originators of leading theories were requested to use the exact input data provided here in their blind predictions of the test cases. The input data include all of the elastic constants, ultimate strains and strengths and the nonlinear stress-strain curves for the unidirectional laminae and their constituents. Various types of laminates, chosen for the analysis, are described together with the lay-up, layer thicknesses, stacking sequences and the loading conditions. Detailed instructions, issued to the contributors, are also presented at the end of this paper. © The Author(s) 2013.


Kaddour A.S.,QinetiQ | Hinton M.J.,National Composites Center | Smith P.A.,University of Surrey | Li S.,University of Nottingham
Journal of Composite Materials | Year: 2013

This paper provides a set of concluding remarks on Part A of the third world-wide failure exercise where a comparison has been made between the capabilities of 12 different mathematical models for predicting the evolution of matrix cracking, damage and failure in continuous fibre-reinforced polymer composites when subjected to multi-axial loading. The originators (or their collaborators) of those theories have employed their methods to 13 carefully selected challenging problems (test cases) addressing the cracking and damage evolution arising from ply thickness, lay-up sequence, size effects and a variety of loading conditions (biaxial, bending, thermal loading and loading-unloading) of a number of unidirectional and multi-directional glass and carbon epoxy laminates. These covered eight different lay-ups consisting of 0 , [0 /90 /0 ], [0 /90 8/0 ], [0 /90 ]s, [±45 ]s, [±50 ]s, [30 /90 /-30 /90 ]s and a family of [0 m/45 m/90 m/-45 m]s, [45 /0 /90 /-45 ]s and [0 /45 /-45 /90 ]s quasi-isotropic laminates. Key features in each theory are identified including: types of damage models employed, whether linear or nonlinear analysis was carried out, reliance on software and numerical methods and identification of modes of damage. The results of stress-strain curves, crack density and damage curves have been superimposed and bar charts were constructed to show similarities and differences between the predictions of the various theories. © The Author(s) 2013.


Grant
Agency: GTR | Branch: EPSRC | Program: | Phase: Training Grant | Award Amount: 4.93M | Year: 2014

The global Robotics and Autonomous Systems (RAS) market was $25.5bn in 2001 and is growing. The market potential for future robotics and autonomous systems is of huge value to the UK. The need for expansion in this important sector is well recognised, as evidenced by the Chancellor of the Exchequers announcement of £35m investment in the sector in 2012, the highlighting of this sector in the 2012 BIS Foresight report Technology and Innovation Futures and the identification of robotics and autonomous systems by the Minister for Universities and Science in 2013 as one of the 8 great technologies that will drive future growth. This expansion will be fuelled by a step change in RAS capability, the key to which is their increased adaptability. For example, a home care robot must adapt safely to its owners unpredictable behaviour; micro air vehicles will be sent into damaged buildings without knowing the layout or obstructions; a high value manufacturing robot will need to manufacture small batches of different components. The key to achieving increased adaptability is that the innovators who develop them must, themselves, be very adaptable people. FARSCOPE, the Future Autonomous and Robotic Systems Centre for PhD Education, aims to meet the need for a new generation of innovators who will drive the robotics and autonomous systems sector in the coming decade and beyond. The Centre will train over 50 students in the essential RAS technical underpinning skills, the ability to integrate RAS knowledge and technologies to address real-world problems, and the understanding of wider implications and applications of RAS and the ability to innovate within, and beyond, this sector. FARSCOPE will be delivered by a partnership between the University of Bristol (UoB) and the University of the West of England (UWE). It will bring together the dedicated 3000 square metre Bristol Robotics Laboratory (BRL), one of the largest robotics laboratories in Europe, with a trainin and supervising team drawn from UoB and UWE offering a wide breadth of experience and depth of expertise in autonomous systems and related topics. The FARSCOPE centre will exploit the strengths of BRL, including medical and healthcare robotics, energy autonomous robotics, safe human-robot interactions, soft robotics, unconventional computing, experimental psychology, biomimicry, machine vision including vision-based navigation and medical imaging and an extensive aerial robotics portfolio including unmanned air vehicles and autonomous flight control. Throughout the four-year training programme industry and stakeholder partners will actively engage with the CDT, helping to deliver the programme and sharing both their domain expertise and their commercial experience with FARSCOPE students. This includes regular seminar series, industrial placements, group grand challenge project, enterprise training and the three-year individual research project. Engaged partners include BAE Systems, DSTL, Blue Bear Systems, SciSys, National Composites Centre, Rolls Royce, Toshiba, NHS SouthWest and OC Robotics. FARSCOPE also has commitment from a range of international partners from across Europe, the Americas and Asia who are offering student exchange placements and who will enhance the global perspective of the programme.


Hou Y.,Donghua University | Hou Y.,University of Bristol | Tai Y.H.,University of Sheffield | Lira C.,University of Bristol | And 4 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2013

We describe the bending and failure behaviour of polymorphic honeycomb topologies consisting of gradient variations of the horizontal rib length and cell internal across the surface of the cellular structures. The novel cores were used to manufacture sandwich beams subjected to three-point bending tests. Full-scale nonlinear Finite Element models were also developed to simulate the flexural and failure behaviour of the sandwich structures. Good agreement was observed between the experimental and FE model results. And the validated numerical model was then used to perform a parametric analysis on the influence of the gradient core geometry over the mechanical performance of the structures. It was found that the aspect ratio and the extent of gradient (i.e. the horizontal rib length growth rate or the internal angle increment) have a significant influence on the flexural properties of the sandwich panels with angle gradient cores. © 2013 Elsevier Ltd. All rights reserved.


Agnese F.,University of Bristol | Remillat C.,University of Bristol | Scarpa F.,University of Bristol | Payne C.,National Composites Center
Composite Structures | Year: 2015

The work describes a structural composite damper concept based on a chiral auxetic configuration. Chiral structures couple uniaxial and rotational deformations to provide a negative Poisson's ratio behaviour and high dissipation through shear strain energy, and this feature is exploited by up-scaling the deformation mechanism of the chiral cell to design a damper that dissipates energy in the edgewise/shear modes, like the ones occurring in wind turbine blades. The damper concept and its configuration are evaluated through a series of Finite Element parametric and probabilistic models. A small-scale demonstrator is manufactured and subjected to compressive cyclic loading at increasing maximum displacements. Good agreement between the numerical and experimental force-displacement and energy dissipated-displacement curves is observed, showing the feasibility of the chiral composite damper concept for vibration damping-related applications at low frequencies. © 2015 Elsevier Ltd.


Dell'Anno G.,National Composites Center | Treiber J.W.G.,Cranfield University | Partridge I.K.,University of Bristol
Robotics and Computer-Integrated Manufacturing | Year: 2016

The paper aims at providing practical guidelines for the manufacture of composite parts reinforced by tufting. The need for through-thickness reinforcement of high performance carbon fibre composite structures is reviewed and various options are presented. The tufting process is described in detail and relevant aspects of the technology are analysed such as: equipment configuration and setup, latest advances in tooling, thread selection, preform supporting systems and choice of ancillary materials. Effects of the process parameters on the preform fibre architecture and on the meso-structure of the reinforced component are discussed. Special emphasis is given to the different options available in terms of tuft insertion and loops management. Potential fields of application of the technology are investigated as well as the limitations of its applicability in relation to preform nature and geometry. Critical issues which may arise during the manufacturing process concerning thread insertion, loops formation, alteration to the fabric fibres layout or local volume fraction are identified. Copyright © 2015 Published by Elsevier Ltd. All rights reserved.


Kaddour A.S.,QinetiQ | Hinton M.J.,National Composites Center
Journal of Composite Materials | Year: 2013

This article draws to a conclusion the results from the co-ordinated study known as the Second World-Wide Failure Exercise (WWFE-II). It contains an objective assessment of the performance of 12 leading failure criteria for predicting the response of fibre-reinforced polymer composites when subjected to 3D states of stress. Twelve challenging test problems (Test Cases) were defined by the organisers of WWFE-II, encompassing a range of materials (polymer, glass/epoxy, carbon/epoxy), lay-ups (unidirectional, angle ply, cross ply and quasi-isotropic laminates) and various 3D stress states (various triaxial strength envelopes, through-thickness and shear loading, and stress-strain curves). A systematic comparison has then been conducted between 'blind' predictions (i.e. without access to the experimental results beforehand) made for each Test Case by the originators of each theory and previously obtained experimental results for each Test Case. In-depth quantitative and qualitative ranking procedures have been employed to identify the strengths and weaknesses of each theory, and the overall effectiveness of each theory as a potential design tool. The theories are grouped according to their degree of maturity and ability to predict accurately the 3D behaviour of composites. The results from this study provide unique information to the community, the intent being that it will form a guide for the selection of the most appropriate failure theory for use in a given design situation. © The Author(s), 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.


News Article | December 15, 2016
Site: www.materialstoday.com

Composites Germany reports that nearly 250 delegates came to the 2nd International Composites Congress, which took place in Dusseldorf last November. Guests came from over 20 countries and the 2016 partner country was Japan. The list of Japanese guest speakers included Professor Takashi Ishikawa from the National Composites Center Japan, who gave the keynote talk with a comprehensive overview of developments in Japan’s composites technology and its market prospects. The program also included topics such as process technology, material developments, new composite applications, e.g. in architecture, as well as lifecycle analysis and recycling. The next International Composite Congress will be held in Stuttgart from 18 to 19 September 2017. This story is reprinted from material from Composites Germany, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.

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