The purpose of the annual WAC prize is to encourage the further professional development of young engineers following graduation with a first degree. This year’s competition attracted a number of papers from post graduate researchers all over the South West; four were chosen as finalists. Steve Hancock’s presentation entitled “Using drape modelling to instruct the manual lay-up of woven fabric reinforcement for complex shaped composite components” was the eventual winner. Runners up were Simon Ritchie of Cranfield University with “On the application of Particle Image Velocimetry to Transonic Flow over Rectangular Cavity Flow”, Markus Deittert of The University of the West of England with “Dynamic Soaring as a primary means of propulsion for small UAVs” and Paul Williams of Rolls-Royce with “Turbine Blade Product Cost Prediction using Data Mining”. The following is a brief overview of Steve Hancock’s work:

“Our work at the University of Bristol reviews the use of draping simulation techniques for woven reinforcements in advanced composites and considers how such simulation tools are conventionally used in the design
process to aid manufacture of complex shaped components. While much work in the field has concentrated on predictive modelling for mechanically
formed components, our work focuses on characterising manual drape forming techniques and how they are employed to form highly complex shaped components where mechanical forming operations would be
inadequate. A study of manual drape trials for a variety of different
shapes was completed and the results show that hand lay-up techniques can be broadly characterised and simplified to facilitate a deeper understanding of manual lay-up operations.

The method used to characterise manual lay-up separates the fabric manipulations into discreet categories based on direction of manipulation and the location of manipulation force applied to deform the material to a complex three dimensional shape. This characterisation is then employed in a novel strategy developed at the University of Bristol for extending the current kinematic drape simulation technology. The strategy relates experimentally-derived practical lay-up rules to a simulated draped pattern showing only tow trajectories and extracts additional information to generate a set of detailed unambiguous manufacturing instructions that can be passed to the lay-up operator. It involves the analysis of both in and out-of-plane tow curvature for a particular draped pattern and it was shown that tow curvature, representing the rate of change of fabric deformation over a preform, can be used to extract the dynamic behaviour of the forming process in general. The work shows that conventional outputs from drape modelling are of limited applicability in informing the hand lay-up process for complex surfaces but that, by incorporating manufacturability constraints, the simulation tool can inform both the design phase and the lay-up process, whilst generating lay-up instructions during the design process effectively conveys the design intent to the manufacturers, improving lay-up time, repeatability and tolerances between
components.”

Steve Hancock can be contacted at steve.hancock@bristol.ac.uk or at the Department of Aerospace Engineering, University of Bristol, Queens Building, University Walk, Bristol, BS8 1TR.

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