practice in small boatyards around the world and requires relatively low capital investment. Infusion typically leads to lower void content and higher fibre volume fractions than wet lay-up. When cutting edge performance
the void content, compaction and uniformity of samplesmade with G-vent are comparable with laminates of the same thickness made in an autoclave.’ If the quality of composites
produced is impressive for someone working in America’s Cup quality control, then they should be good enough for anyone. The construction of composite
parts by wet lay-up, where a resin is rolled onto some fibre in the same way youmight paint a wall, is simple enough to be done in the garden shed but will lead to high void content and also a low fibre volume fraction (meaning there is less structurally important fibre andmore resin per unit of composite produced). Building composite parts via
infusion requires a vacuum pump to suck resin through the fibre and a little more expertise, but is common
:
G-Vent is a microscopic- ally thin layer that acts as a network of pathways in the pre-preg material to let it “vent” :
G-Vent was developed primarily for commercial shipping wing sails, but racing sailors will see great benefits. :
G-Vent is equally suitable for thick section parts
is needed, pre-preg fibres are used, delivering remarkably low void content and high fibre volume fractions due to the uniform distribution of resin throughout the fibre. As a result components built with pre-preg can be lighter and stiffer and more reliable than those built by any other method. Unfortunately, when it comes to practicality and ease of manufacture pre-preg starts to get more complicated. First of all the fibre is pre-impregnated with a precise amount of resin in the factory, but it must then be kept refrigerated until it is used, to stop it curing. Secondly, debulking (a process in which air is sucked out of the composite part via a vacuum) is typically needed after every two layers of fibre are laid. Thirdly, composite laminates which are more than a few millimetres in thickness are best cured in an autoclave at high temperature and high pressure. The debulking process is laborious, leading to both extra cost and very long lead times for thick composite parts that may be hundreds of layers thick. Autoclaves large enough to fit boats or superyacht masts inside are extremely expensive bits of kit that even some of the performance sailing industry’s biggest players struggle to justify financially. The closest available autoclave might be a very long way from where you want your large composite object to end up, leading to substantial delivery costs. As a result, constructing a boat in pre-preg can be prohibitively expensive for most of us and even in
the America’s Cup world when budgets may be less constrained, the lead time needed to produce a new foil design has a direct impact on the entire development programme. G-Vent pre-preg technology can be used to produce complete components or combined with standard pre-pregs and used in thicker parts of a component, and it appears to resolve many of these constraints, providing an optimised processing solution for the highest quality thick section composite parts. Tom James, marine business
development manager at Hexcel, highlights that Wind Assisted Ship Propulsion (WASP) systems are predicted by many to have a huge impact on the shipping industry, and significant research and development funding is available from within the industry and at government level. Many WASP systems, including some being developed by naval architects with America’s Cup wing-sail design experience, use a composite wing- sail which is automatically and autonomously trimmed to provide the amount of power required at any given moment. G-Vent technology has been designed to deliver for this potentially lucrative market, in which the sheer size and potential number of wing-sails needed mean that out- of-autoclave production will very likely become an absolute necessity. We will all benefit in some way if
the shipping industries’ impact on global warming can be limited and we wish them success in this endeavour. If high-quality carbon fibre components become quicker and cheaper to build then it is a relatively unimportant side product of such development, but one which many Seahorse readers will very much be looking forward to!
www.hexcel.com
❑ SEAHORSE 65
VPLP DESIGN/OCEANWINGS BY AYRO
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120
