Centre for Fine Print Research University of the West of England Centre for Fine Print Research
17 May 2016

Hybrid auxetic foam and perforated plate composites for human body support

Dates: 17 May 2016

Dr Peter Walters has published a joint publication in the Basic solid state physics journal

Co-Authors: H. Mohanraj (University of Bristol). S. L. M. Filho Ribeiro (University of São João del Rei). T. H. Panzera (University of São João del Rei). F. Scarpa (University of Bristol). I.R. Farrow (University of Bristol). R. Jones (MS Research, Treatment and Education, The Vassall Centre, Bristol). A. Davies-Smith (MS Research, Treatment and Education, The Vassall Centre, Bristol). C. D. L. Remillat (University of Bristol). H.-X. Peng (Zhejiang University). P. Walters (UWE Bristol).
The article describes the design, manufacturing, modelling and testing of a hybrid composite support made from auxetic open cell foam liners and curved thermoplastic plates with rhomboidal perforations for human body support. Both the foam and the curved perforated plate have in-plane negative Poisson's ratio behaviour. The static bending stiffness of the hybrid auxetic composite support is modelled using an analytical and Finite Element approach benchmarked against experimental results from three-point bending tests. The benchmarked Finite Element models are used to develop a map of optimised static stiffness versus the geometry of the rhomboidal perforations. A Design of Experiment testing campaign is also carried out on 16 hybrid auxetic composite plates to understand the interaction and correlation of the static bending versus the geometry of the perforations and the contribution given by the auxetic foam liner.

Date published: 17 May 2016
Basic solid state physics journal
DOI: 10.1002/pssb.201600106
Volume: 253
Issue: 7
Pages: 1378-1386

An anthropomorphic design for a minimally invasive surgical system based on a survey of surgical technologies, techniques and training

Authors: Tzemanaki, A., Walters, P., Pipe, A. G., Melhuish, C. and Dogramadzi, S.
Publication: International Journal of Medical Robotics and Computer Assisted Surgery
ISSN: 1478-5951
Date: November 2013
Url: http://dx.doi.org/10.1002/rcs.1544

Over the past century, abdominal surgery has seen a rapid transition from open procedures to less invasive methods such as robot-assisted minimally invasive surgery (MIS). This paper aims to investigate and discuss the needs of MIS in terms of instrumentation and to inform the design of a novel instrument. Methods: A survey was conducted among surgeons regarding their opinions on surgical training, surgical systems, how satisfied they are with them and how easy they are to use. A concept for MIS robotic instrumentation was then developed and a series of focus groups with surgeons were ran to discuss it. The initial prototype of the robotic instruments, herein demonstrated, comprises modular rigid links with soft joints actuated by shape memory alloy helix actuators; these instruments are controlled using a sensory hand exoskeleton. The results of the survey, as well as the ones of the focus groups, are presented here. A first prototype of the system was built and initial laboratory rests have been conducted in order to evaluate this approach. Conclusions: The analysed data from both the survey and the focus groups justify the chosen concept of anthropomorphic MIS robotic instrumentation which imitates the natural motion of the hands.

Artificial heartbeat: design and fabrication of a biologically inspired pump

Authors: Walters, P. Lewis, A. Stinchcombe, A. Stephenson R. and Ieropoulos, I.
Publication: Bioinspiration and Biomimetics Vol. 8 No.4
Date: November 2013
url: http://iopscience.iop.org/1748-3190/8/4/046012

We present a biologically inspired actuator exhibiting a novel pumping action. The design of the 'artificial heartbeat' actuator is inspired by physical principles derived from the structure and function of the human heart. The actuator employs NiTi artificial muscles and is powered by electrical energy generated by microbial fuel cells (MFCs). We describe the design and fabrication of the actuator and report the results of tests conducted to characterize its performance. This is the first artificial muscle-driven pump to be powered by MFCs fed on human urine. Results are presented in terms of the peak pumping pressure generated by the actuator, as well as for the volume of fluid transferred, when the actuator was powered by energy stored in a capacitor bank, which was charged by 24 MFCs fed on urine. The results demonstrate the potential for the artificial heartbeat actuator to be employed as a fluid circulation pump in future generations of MFC-powered robots ('EcoBots') that extract energy from organic waste. We also envisage that the actuator could in the future form part of a bio-robotic artwork or 'bio-automaton' that could help increase public awareness of research in robotics, bio-energy and biologically inspired design.

Journal front cover

Reproduction in Three-Dimensional Inkjet Printing

Authors:M. Stanic, B. Lozo and P. Walters
Publication:Journal of Imaging Science and Technology, Volume 54
issn: 1062-3701
date:November 2010
url: http://www.imaging.org/IST/store/physpub.cfm?seriesid=1&pubid=955


Three-dimensional printing is a powder-based solid freeform fabrication technique. It is based on conventional ink jet printing technology, basic materials being powders and binders (inks). As the process uses coloured binders, text and graphic elements can be reproduced on the objects. The reproduction of three-dimensional prints surface elements was evaluated, also using image analysis, which was studied as a tool for reproduction evaluation. A test target, consisting of selected geometric and text elements, was placed on the surface of designed three-dimensional plate. The test plates were placed in different relative xyz positions, as well as printed with different preferences. The evaluation was done on light microscope captures, while scanned images of three-dimensional prints surfaces were used and observed as well. Changes in three-dimensional printed surface elements reproduction due to the objects’ positioning and printing preferences, and binder-powder interactions were discussed. Specific image analysis procedures were researched as a tool for objective reproduction evaluation. The authors wish to thank several persons for their help, support and advice; Edo Sternad, Andrej Žužek, Kristjan Celec, Ib-Procadd, Slovenia. Materials for the three-dimensional printing and printing services supplied by Ib-Procadd, Ljubljana, Slovenia. This work is partly funded by the Croatian Ministry of Science, Education and Sports Project Reference No. 128-0000000-3288.

Artifact Journal, Front cover image

New technologies for 3D realization in Art and Design practice

Author/Co Author: Dr Peter Walters and Dr Paul Thirkell
Publication: Artifact, Volume 1, Issue 4, pages 232 - 245
Publisher: Taylor and Francis,
Date: 2007
URL Links: www.informaworld.com


As digital design technologies become ever more widespread, CAD-CAM, virtual and rapid prototyping techniques are increasingly being exploited by creative practitioners working in areas outside the industrial design and engineering contexts in which these technologies are currently predominantly employed. This review paper aims to critically examine work by artists, craft practitioners, and designer-makers who creatively engage with these new and rapidly emerging technologies and, by doing so, extend their own practice and push at the boundaries of art and design disciplines.

Historic precedents for new 3D technologies in the fine and applied arts are identified, and writing by Heidegger, Baudrillard, and Virilio informs the critical review of work by art and design practitioners in sculpture, metalwork, jewellery, and ceramics. The discussion reflects on relationships between art and technology and physical and virtual making, and concludes by pointing to the possibility of new “hybrid” forms of practice which bridge the gap between physical and virtual design worlds. The paper closes by suggesting that the notion of “truth to materials” in the arts and crafts might now be extended to one of “truth to virtual materials”, as practitioners creatively negotiate relationships between digital cause and physical effect.

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This is a preprint of the abstract of an article whose final and definitive form has been published in the journal Artifact ©2006;