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Composites news
news Anyone for tennis? An entirely new concept in the manufacture of tennis rackets has been designed and developed by Dunlop Sports Company at their Research and Development Centre at Horbury, England. The aim to produce a strong light-weight racket frame which would be efficient, and cost-effective in manufacture has been fulfilled, it is felt, with the Max 150G - - a hollow frame made from carbon fibre-reinforced nylon and subsequently filled with polyurethane foam. The manufacturing process was as follows: a core (the shape of a tennis racket, but slightly smaller in section) was cast in a eutectic metal alloy which had a melting point of 140°C and then placed in an injection mould, slightly larger in dimensions. The t h e r m o p l a s t i c material was then injected to completely sheath the core. The temperature of the thermoplastic material was 280°C, but it was found that the larger mass of metal rapidly conducted the heat away from the plastic, allowing it to cool and harden before the metal melted and distorted. The moulding and core were then removed from the injection mould and put into an oven, to melt out the metal core and leave the hollow racket frame (Fig. 1). Finally the frame was filled with polyurethane foam; a low density foam was used in the head region to dampen vibration (see Fig. 2) and ensure good balance, and a foam of medium density was used in the handle area to provide a rigid base for the grip. The proportioning and positioning of the foam can be varied to suit players' requirements for racket balance and weight. Two special features were incorporated into the Max 150G frame. The first involved moulding the stringing holes directly into the frame by using retractable pins in the injec-
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oss the inside of the frame (as shown in Fig. 1). The whole process of production is directly applicable to large scale production. It is also expected that the process will have applications in other areas of industry where strong, light-weight, accurate, and complicated mouldings are needed.
Fig. 1 The hollow frame of the Max 150G, showing internal support columns and reinforced stringing holes around the head
tion mould. The second, was the incorporation of strengthening pillars into the hollow structure at the exact positions where the high string tensions are applied to the frame. This was achieved by arranging holes in the core to coincide with the special pins (which were slightly smaller in diameter than the holes in the core) thus allowing the flow of thermoplastic material to create hollow support columns acr-
Further details from: Dunlop Limited, 10-12 King Street, St. James's, London SWIY 6RA, England.
Long-lasting 'You cannot put an old head on young shoulders' but you can put an old truck body on a new chassis and this is what has happened to the 14 ft (4.27 m) container shown in Fig. 3. Used for carrying spare components to BBC transmitting stations (often in very remote areas) all over Great Britain, the container had already travelled over
Fig. 2 Vibration damping studies on the finished racket, The ball is fired from a compressedair gun at the suspendedracketand the vibration trace is electronicallydisplayed
COMPOSITES . APR I L 1981
newsl 100 000 miles (161 x 10~ km) as the body on a Dodge RGO8 chassis. It has now been transferred (together with its original tail-lift) to a new RG09, G8685 model chassis which incorporates an extra large fuel tank, to continue its duties; thus proving suitability and durability of the 'Glasonit' - - w o v e n roving glass fibre-reinforced plastic manufactured by Technical Panel Industries Limited - - material from which the container is made.
strength is given as 235 J/m and compares favourably with values of 71 J/m for 'standard' grades. This, it is claimed, has been achieved with only minor reductions in strength and stiffness. 'Zytel' 80G-33 has been heat stabilized for use at elevated temperatures and in paint ovens and is expected to be used for wheels, chain saw housings, heavy duty engine fans, sporting goods, and under-the-bonnet automotive components.
Full details of 'Glasonit' grp panels are available from: Technical Panel Industries Limited, 4 Hollands Road, Industrial Estate, Haverhill, Suffolk, CB9 9LH, England.
'Zytel' FE 8018, containing 14% glass fibre reinforcement, has been developed for applications that require toughness but not the high stiffness of 'Zytel' 80G-33.
Tough and even tougher A 'super-tough' grade of glass fibre-reinforced nylon (containing 33% glass fibres) designated 'Zytel 80G-33 ', has been developed by the Du Pont Company. The Izod impact
'Zytel' 80G-33 is available in neutral colour only but a black grade is under development, as also is a grade containing 43% glass fibres. Further information from: Du Pont de Nemours International S.A., PO Box Ch-1210 Geneva 24, Switzerland.
The front panel of a train which will run on the Brussels Metro (claimed to be one of the most modern transport services in Europe) made from BP Chemicals Cellobond glass fibre-reinforced polyester resin. Being light in weight the use of grp panels gives a cost saving in terms of energy. The grp panels also have good weathering ability; some units have already been in operation for up to four years and have retained a good appearance, indicating a further saving on maintenance and cleaning. For further information on Cellobond polyester resins: BP Chemicals Limited, Speciality Plastics Division, Barry Factory, Sully, Penarth, South Glamorgan CF6 2YU, South Wales.
No guide lines
Fig. 3 The new transit van for specialized components needed by transmitting stations comprising the well-worn container on a new chassis
COMPOSITES. APRI L 1981
Trend Machinery and Cutting tools have introduced a new type of self-guiding trimming cutter for plastic laminates. The Trend 46/2 SG is claimed to trim faster than conventional cutters and can be used by semi-skilled labour. Dispensing with the need for fitting standard guides, the cutter maintains an accurate course by means
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news of a roller bearing, mounted on the cutter base, which follows the edge of the underlying board. The cutting edge of the Trend 46/2 SG is at 90 ° but similar cutters with cutting edges at 80 °, 60 °, 45 °, and 30 ° can be obtained.
Trend Machinery and Cutting Tools Ltd, Unit N, Penfold Works, Imperial Way, Watford, Herts, WD2 4YY, England. To t r a n s m i t the load A reinforcement of 2 0 - 5 0 % a l u m i n i u m in an ultra high molecular weight polyethylene has been found to improve its modulus of elasticity, its c o m p r e s s i v e strength, and its thermal conductivity. Sheets of such a material have been produced by Solidur Plastics Limited and can be obtained in differing compositions and qualities. The material is claimed to be ideal for load transmission applications where high impact strength is required and has been successfully used as a buffer behind the chuck of a steel pile-driving-cap. Many other uses in engineering industries are envisaged for this material.
Fig. 4 A recently-built exhibition centre in Kent, England, showing the exterior roof cladding panels madefrom Telacor,an aluminium/polyethylene composite material
exhibition centre are made from white Telacor and the internal roof decking is made from Telatherm 900 which comprises 'Korrugal' metal skins bonded to a polyurethane core.
Further information from: Solidur Plastics Limited, Maybrook Road, Brownhills, Walsall, WS8 7DG, England.
Further details from: Teal Claddings Limited, Halesfield Industrial Estate, Telford, Shropshire, England.
Roof decking
Glass fillings
The exterior beige-coloured fascia panels on the roofing of an exhibition centre (Fig. 4) at Hempstead, Kent, England have been made from Telacoran aluminium polyethylene composite material, supplied by Teal Claddings Limited. The panels conceal the substantial guttering systems, specially designed to disperse water from the large roof expanse. The light-weight and low cost panels are claimed to have very flat surfaces that encourage an effective self-cleansing action. Interior fascia panels within the
The following products, which can be used for reinforcements in plastic materials, have been introduced onto the market by TBA Industrial Products Limited:
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MAT. 79, an emulsion bound chopped strand mat, produced from a fine, high integrity strand and made to a very tightly controlled mass/ unit area specification is intended to assist moulders to achieve consistent-weight mouldings. Its open structure affords rapid resin penetration and air release. MAT. 79 meets the requirements of BS
3496: 1973 and is approved by Lloyd's Register of Shipping for craft constructed under their survey, and by Dot Norske Veritas. ECR 1668 and ECR 1677 are filament winding rovings suitable for use on all proprietary and custombuilt filament winding machines. The dressing used on these rovings gives rapid resin penetration and fast wet-out; it contains a silane coupling agent which ensures compatability with orthophthalic, isophthalic, and bisphenol polyester resins and also with vinyl ester and epoxide resins. Further details from: TBA Industrial Products Limited, PO Box 40, Rochdale, Lancs, OL 12 7EQ, England. Satellite shielding A composite sandwich material with the highly specialized function of protecting space satellites from damage caused by high energy
COMPOSITES . APR I L 1981
news Preview The following is a preview of some forthcoming events, arranged in chronological order, Further details can be obtained from the addresses given at the end of each item, A comprehensive list of future meetings relating to composite materials can be found in the Calendar section.
The following short courses are being arranged at various university locations during the year: At the UCLA, Los Angeles, USA,
Materials aspects of damage tolerance, to be held on 6-10 April 1981,
Sea Falcon, Robin Knox-Johnson's new 70 ft (21.3m) ocean-racing catamaran, launched on 25 October 1980, at Brightlingsea, England, was built with BP Chemicals Cellobond glass fibre-reinforced polyester marine resins, a plywood box girder centre beam, and aluminium for and aft beams; the whole structure weighing 8.5 tonnes. The vessel has been entered for The Observer two-handed transatlantic race this year and Knox-Johnston is hoping to reclaim this and many other trophies for Britain with the Sea Falcon. BP Chemicals Limited, Be/grave House, 76 Buckingham Palace Road, London SW1W OSU, England.
electron bombardment has been developed and successfully tested by the Dynamics Group of British Aerospace. The material is made from Kapton (or Teflon) sandwiched between two layers of a very conductive material - - either aluminium or carbon - - with a very thin layer of Kapton on top. Electrically conductive paint around the edges of the material allows the conductive layers to be earthed to the main structure of the satellite. The purpose of the composite is to dissipate a surface charge the moment it encounters the spacecraft without allowing it to build up. Electrons penetrating the ultra-thin outer
COMPOSITES . APRI L 1981
Kapton skin are captured by the conducting layer and conducted away to the spacecraft structure; similarly, very energetic charged particles are captured by the innermost conductive layer. This material has been so devised that it will inhibit the build-up of high voltage charges without reducing the thermo-optical protective properties of the material to any significant extent. Further information from: British Aerospace Dynamics Group, Space and Communications Division, Gunnels Wood Road, Stevenage, Herts, SG1 2AS, England.
is intended for designers, manufacturers and users of all kinds of structural and constructional materials. It will concentrate on the aerospace, automotive, and energy production industries, considering how best to use the basic concepts of fracture mechanics to avoid both failures and overdesign of structural and constructional components and thereby to achieve savings in material, operating, and failure costs. Design-
ing with structural fibrous composites, to be held on 13-17 April 1981, will cover both the materials and structural aspects of composites. The purpose of the course is to impart a basic understanding of the properties and behaviour of loadbearing fibrous composites. Manufacture and design problems and also techniques where no codes of practice are available, will be discussed. Details of both courses can be obtained from: Continuing Education in
Engineering and Mathematics, UCLA Extension, PO Box 24901, Los Angeles, CA 90024, USA. At The U n i v e r s i t y of Surrey, Guildford, England, The technology
of fibre-reinforced plastics composite materials, to be held on 13-16 July 1981, is described as an intens-
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lnews ive course for engineers, materials scientists and chemists concerned with fibre-reinforced plastic materials, particularly in the aerospace, automotive, marine and general engineering industries. It aims to relate the service performance of polymeric-matrix composites to their constitution and to the processing variables. The emphasis will be on practical systems of relevance to the various markets. The course will span matrix chemistry, curing, fabrication, testing and service performance as well as a review of the basic principles of reinforcement in both continuous and discontinuous fibre systems. Such areas as: short term properties of frp; properties of
matrices (resins), fibres and interfaces; long term properties - - creep, fatigue, durability and toughness; short-fibre moulded materials; the selection and fabrication of composites in relation to performance requirements; testing and evaluation of composite materials; and durability of grp in aggressive environments; will be covered. Full details are available from: Mr. M.G. Bader, Department of Metallurgy and Materials Technology, University of Surrey, Guildford, GU2 5XH, Surrey, England. At The University of Cambridge, England, Designing with fibrous
StPandGlassfibre
composites, will be held on 6-11 September, 1981. The course will take place at The Department of Engineering with accommodation at Peterhouse College and is intended to bring together materials scientists, designers, engineers, fabricators, and end users concerned with the design, manufacture, evaluation and use of fibre-reinforced structures and products. It will cover both materials and structural aspects of composites. Design problems and procedures will be examined, especially in cases where no codes of practice are available. Focus of attention will be on the properties and behaviour of load-bearing composites. The titles of lectures
Welding and Metal Fabrication
nowdeliHng
anew balsacore
material... lite.I We've extended our range of formers and core materials even more to include Corelite - end-grain, kilndried balsa blocks laminated to a glassfibre scrim. It is supplied in 48" x 18" sheets with standard thicknesses of3/g' ~/2;'s/g,and 3/~,making it easier to handle with less wastage in trimming.The blocks are only 1" square, so the material conforms easily to difficult mould contours and helps to eliminate voids. T h e consistent density and Lloyds approval also assures the manufacturer of a stable product to meet design and strength specifications. Corelite is available from our local branches throughout the country. For more information, contact our H e a d Office on 01-568 7191 or telex your order on 8951065.
GUIDE 81 U p d a t e d and e x p a n d e d for 1 9 8 1
Comprehensive listings of: • Metal fabricators • Metal stockholders • Services and equipment sources PRICE O N L Y £ 1 0 Further details from: The Editor, Welding and Metal Fabrication, PO Box 63, Westbun/House, Bun/Street, Guildford, Surrey GU2 5BH England Telephone: 0483 31261
Telex 859556 Scitec G
Brentway Trading Estate, Brenfford, Middlesex T W 8 8ER.
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COMPOSITES . APR I L 1981
newsl will include: mechanical properties, test methods, data acquisition and analysis; manufacturing methods, processing and quality assurance; structural applications n design methods and design configurations; environmental induced degradation; non-destructive evaluation; reliability and damage tolerance; and failure analysis, fracture toughness, and micromechanisms of crack extension. Further details from: Dr P.W.R. Beaumont, Fracture Analysis International Ltd, East England Office, Westwood House, Dukes Meadow Stapleford, Cambridge, CB2 5BH, England. At The U n i v e r s i t y of Bristol, England, Materials aspects of damage tolerance, to be held on 14-18 September 1981 will examine how fracture mechanics concepts can be used to overcome failures and overdesign of structural and constructional components thereby making savings in costs. Engineering materials to be examined will include metals, ceramics, glass and composites. The course is intended for holders of a science or engineering degree or those with a wide experience in materials technology. Subjects to be covered will include: concept of damage tolerance; ceramics, and other materials when exhibiting brittle behaviour; metals, including welds; adhesives and adhesive joints; polymers and composite materials. Further details from: Dr K.H.G. Ashbee, Fracture Analysis International Ltd, West England Office, 2 Druid Stoke Avenue, Stoke Bishop, Bristol, BS9 1DD, England. The second international symposium on Energy and composite materials is due to be held in Venice, Italy, 3, 4 and 5 June 1981. Organized j o i n t l y by I n s t i t u t
COMPOSITES. APR I L 1981
Francais du Petrole, Amoco Chemicals Europe, and Owens Corning Fiberglas Europe, the symposium will comprise 50 lecturers and also a poster session on the energy content of composite materials and their uses in: traditional energy applications; alternative energy applications; and transportation. Further information can be obtained from: G~rard Bonavent, Institut Fran£ais du Petrole, 1 et 4 avenue de Bois-Preau, B.P. 311, 92506 Rueil Malmaison, France. An i n t e r n a t i o n a l c o l l o q u i u m arranged by the CNRS on Plastic behaviour of anisotropic solids is due to take place in Grenoble, France, on 15-19 June 1981. It is intended to specialize in the study of the mechanical behaviour at large plastic deformation of solids which have either initial anisotropy or 'induced' anisotropy (caused by deformation, hardening, damage etc). It intends to bring together the study of macroscopic phenomenological behaviour using continuum mechanics and the study of the directional properties of the internal structure and by so doing, improve the mathematical modelling of anistropic solids, such as composite materials, metals, soils and rocks. There is a call for papers in such areas as: formulation of constitutive laws at large irreversible deformations within non-linear continuum mechanics; correlations between the material oriented structure and the directional character of the appearance and growth of cracks, voids and discontinuity lines; correct interpretation of 'off-axis' tests up to damage and failure; influence of the loading path under complex stresses; homogenization of the material with internal oriented structure; numerical formulation for anistropic materials at large deformations; and experiments on the
behaviour of structures. Participation in the colloquium will be by invitation. Interested authors are requested to send a summary (800-1000 words) by 30 March 1981 to: M.J.P. Boehler, Institut de Mechanique (IMG), B.P. 53 X, 38041 Grenoble Cedex, France. An International conference on the science of hard materials is to be held at Jackson Lake Lodge, Wyoming, USA, on 23-28 August 1981. This is described as an in-depth conference which will consider the fundemental physical and chemical properties of hard materials, particularly transition metal carbides, borides, and nitrides and their influence on the mechanical behaviour and structure/property relationships in hard metal composites. The application of the most recent analytical methods to the study of hard materials will be appraised. Main topics for consideration will be: fundamental properties, microstructure, mechanical behaviour, surface treatments, and new horizons. F u r t h e r d e t a i l s f r o m : R.K.V. Viswanadham, Materials Research, Reed Rock Bit, Houston, Texas 77001, USA. The sixth biennial plastics seminar on Managing corrosion with plastics is scheduled to take place at the Peachtree Plaza Hotel, Atlanta, Georgia, USA on 26-29 October 1981. Further information from: The National Association of Corrosion Engineers, PO Box 218340, Houston Texas 77218, USA. A two-day seminar organized jointly by The Fillers and Reinforcing Agents Section of the Additives Group of the British Plastics Federation and The Department of NonMetallic Materials, Brunel Univer-
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lnews sity, on The growth in the use of fillers in plastics is planned to take place in the first week of November 1981, in London, England. It is intended that the first day will be concerned with general aspects, such as economy, energy saving advantages of incorporating fillers, and various types of fillers. The second day will be devoted to four application areas: packaging; automotives; domestic applicances; and pipes. The seminar will be aimed specifically at the end-user. There is a call for papers and brief synopses should be sent: Mr S.M.L. Brown,
The British Plastics Federation, 5 Belgrave Square, London SWIX 8PH, England. Further details can also be obtained from the same adress. There is also a call for papers for a conference entitled: Automotive Manufacturing - Update 81. The conference, organized by The Automobile Division of the Institution of Mechanical Engineers is due to take place at their headquarters in London on 1-2 December 1981. Contributions are invited on specific areas of relevance such as: new materials in production of vehicles eg to meet anti-corrosion and safety legislation, and to reduce weight, manufacturing, and wholelife costs, and energy considerations in manufacture. Abstracts (250 words) are to be sent to: Peter Thomas, Secretary, Auto-
mobile Division, The Institution of Mechanical Engineers, I Birdcage Walk, Westminster, London SWTH 9JJ, England, from whom further details can be obtained. on Jointing in fibre-reinforced plastics, arranged by The Department of Aeronautics, Imperial College, in collaboration with The Royal Aircraft Establishment (previously announced for 6, 7 June 1982) is now scheduled to The symposium
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take place on 13, 14 July 1982 at The Imperial College of Science and Technology, London. The aim of the symposium is to bring together workers in the composite materials field, from industry, and from academic and research establishments. It is hoped to cover the four main areas: design; application; testing; and theory. Adhesively bonded joints, bolted and riveted joints, and composite to composite joints will be discussed for all types of fibre-reinforced plastics including: carbon and glass in epoxy; glass in polyester; chopped strand mat and woven roving in polyester; and smc. Such effects as static and fatigue behaviour, failure modes, in-service and environmental effects, and repairs will also be considered. Sponsors of the meeting will include: Carr R e i n f o r c e m e n t s ; Ciba-Geigy; Courtaulds Carbon Fibres Division; and BTR Permali. There is a call for papers and authors wising to participate are invited to send an abstract (200 words) of their proposed paper before 30 September 1981. The papers will be classified as short (5 to 10 min) or long (20 min) and authors are requested to make it clear into which category their paper fits. Authors will be notified by mid-November 1981 if their paper has been accepted; final drafts will be requested by the end of February 1982. Abstracts should be sent to: Mr F.L. Matthews, Aeronautics Department, Imperial College of Science and Technology, London SW7 2BY, England. A conference with the expressed i n t e n t i o n of ' p r o m o t i n g keen discussion, through the use of controversial arguments where necessary' is being planned by The Plastics and Rubber Institute. The conference will be on the subject of The
further use of plastics in the auto-
motive industry and it is intended it will take place about two weeks before the UK Motor Show in October 1982. The subjects to be covered will include: materials developments; processing developments; new components design study where a major item is a plastics moulding; design trends which could influence the choice of - - or even the rejection" of - - plastics parts. Papers on any of the above subjects are being called for and a synopsis (250 words) should be sent by 31 March 1981. A feature of the conference is expected to be a 'design comparison' exercise based on a hypothetical fascia panel. Offers of papers should be sent to:
Mrs Trish Munday, The Plastics and Rubber Institute, 11 Hobart Place, London SW1W OHL, England.
Publications Books for buying Two new publications resulting from a symposium and a conference both held in Los Angeles, USA, in December 1980 and organized by Technology Conferences (the conference, in conjuction with the south California section of the Society of Plastics Engineers) are now available.
Kevlar Composites is a collection of papers presented at a special symposium of the same name. The subjects covered are the development and use of Kevlar aramid fibre-reinforced plastics/composites for a wide range of applications including: aircraft; helicopters; spacecraft; automotives; sporting goods; pressure vessels; etc; together with a section on machining technology for Kevlar composites. The book costs $24.00.
COMPOSITES . APR I L 1981
news Reinforced plastics covers a wide spectrum of current reinforced plastics technology (including materials, processing, applications). It includes a special section by W. Brandt Goldsworthy on Economic advantages of RP/C in high volume applications, and a special feature on the evolution and development of the Windecker 'Eagle' (claimed to be the first successful reinforced plastic airframe structure). The book of the papers from the conference costs $26.00. Both
books are available from: Technology Conferences, PO Box 842, E1 Segundo, CA 90245, USA. The prices given are for the USA, $3.00 should be added for each book by sea mail or $10.00 for air mail. A hand book entitled: A guide to high performance plastics composites provides information for engineers and potential end-users on composites materials containing 50% or more of high modulus fibres. There are sections on the nature of these materials and also manufacturing methods, test methods, and design approaches. Examples of the design of a carbon fibre reinforced drive shaft for a commercial car and a portable lifting frame are cited. There is a glossary section and data sheets for 20 such composites. The book costs £12.50 (£8.00 for BPF members) and is available from: The British Plastics Federa-
tion, 5 Belgrave Square, London SWlX 8PH, England.
Books for free Two new buyer's guides have been announced by The British Plastics Federation. The British Plastics Fed-
eration Buyer's guide for laminated plastics fabrication is issued by the British Laminated Plastics Fabricators Association and provides useful
COMPOSITES . APR I L 1981
information of high pressure decorative laminates to a variety of core materials thus producing hardwearing surfaces used in furniture and fittings. The Guide provides an alphabetical list of members and details of associate members providing services. The British Plastics Federation Buyer's Guide for Plastics Solar Heating Systems and Components contains a chart of suppliers and their products and a list of member companies and affiliates. The BPF also reminds that the following guides have already been issued: Moulded Products and Ser-
vices: Plastics Additives; Thermoplastics Polymers; Compounds and Masterbatches; and Plastics Processing Machinery and Equipment. The BPF also has produced a leaflet entitled: Plastics for the Engineer. This lists the properties of plastics for engineering use, notes on the varieties of each available plastics material, and information on the processes used for producing engineering components. The Guides and leaflet are available from: The British Plastics Federa-
tion, 5 Be/grave Square, London SWIX 8PH, England. Contact moulding by spray deposition is the title of a brochure published by The Glass Fibre Division of TBA Industrial Products Ltd which has recently been revised and brought up to date. The brochure describes all aspects of spray deposition and lists the advantages and disadvantages of the process. It also compares the costs of producing identical mouldings by the spray deposition and hand lay-up techniques. The brochure
is available from:
TBA Industrial Products Ltd, PO Box 40, Rochdale, Lancs, 0L12 7EQ, England.
Lloyd's Register Industrial Services provides an international independant technical and advisory inspection service for all types of industrial plant and machinery. A booklet entitled Lloyd's Register Industrial Services shows the wide areas (both geographical and industrial) over which these services are available. It is available from: The Secretary, Lloyd's Register Industrial Services, Norfolk House, Croydon, CR9 2DT, England. The Industrial Textiles Division of Fothergill and Harvey Ltd has recently issued a brochure entitled:
Woven materials for plastics reinforcement (from glass, carbon, aramid and polyester fibres). Topics covered in the brochure include: fibres for plastics reinforcement, the advantage of woven reinforcements, weave characteristics, fabric finishes, resin compatibility, and hybrid reinforcements. Another section gives e x a m p l e s of how Fothergill and Harvey reinforcements have been used in laminates for aerospace equipment, medical apparatus, ships, building materials, and sporting goods. Copies of the brochure are available from: Fothergill and Harvey Ltd,
Industrial Textiles Division, Summit, Littleborough, Lancs, 0115 9QP, England. Specially prepared to meet the need for greater design data standardization the Performance Plastics Group of ICI Plastics Division has produced six new-style technical data sheets on Maranyl nylon 66 materials. Of these N TD 54 deals specifically with Maranyl glass rein-
forced nylon 66. These are available from: ICI Plastics Division, Welwyn Garden City, Herts, AL7 IHD, England.
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nlrrl=CU
news In touch with TechAlert Over 50 000 reports of publicly-funded research projects are received annually by the Technology Reports Centre in the UK; the majority come from the USA, although the network is worldwide. These reports generally remain unpublished, or are difficult to obtain from source. Summaries of reports likely to be of interest to readers of Composites are now regularly prepared by the Centre and will be included in the News Section in each issue. Full copies of the original reports are available from: TechAlert, Technology Reports Centre, Orpington, Kent, SR5 3RF. The title and reference number given at the end of each item should be quoted with all orders.
Fire tests method for graphite fibre-reinforced plastics A potential problem in the use of graphite fibre-reinforced resin matrix composites is the dispersal of graphite fibres during accidental fires. Air-borne, electrically conductive fibres originating from the burning composites could enter and cause shorting in electrical equipment located in surrounding areas. A test method for assessing the burning characteristics of graphite fibre-reinforced composites and the effectiveness of the composites in retaining the graphite fibres has been developed. The method utilizes a modified Ohio State University Rate of Heat Release apparatus. The equipment and the testing procedure are described. The application of the test method to the assessment of composite materials is illustrated for two resin matrix/graphite composite systems. Further details are given in a 11 page report: Fire test method for graphite fibre-reinforced plastics by
K.J. Bowles, Reference C35/N801807 available as microfiche £1.61 (includiing £2.00.
VAT) or paper-copy
The alleviation of electrical hazards This study was aimed at exploring the feasibility of different approaches to solve the electrical problems posed by graphite fibre-reinforced composites. Four basically different
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approaches were considered: gasification of fibres, retention in the matrix, clumping to prevent entrainment, and electrical insulation of fibres. The techniques used to achieve them are described in some detail. These involved surface treatment of fibres to improve the wettability of fibres and coating the fibres with the selected substances before laying them up for composite fabrication. Thermogravimetric analyses were performed on the plain and treated fibres in inert (nitrogen, argon) and reactive (air) atmospheres. The treated fibres embedded in epoxy were ignited in a Bunsen flame to determine the efficiency of these treatments. A simple apparatus was assembled to detect the time for the first short circuit (in a typical electrical circuit) when exposed to the combustion products from a graphite fibre composite fire. The state-of-the-art and treated fibres cast in typical epoxy were burned and ranked for potential success. It was inferred that the gasification schemes appear promising when reduction or oxidation is tried. It was also found that some very promising candidates were available for the clumping and for the electrical insulation of fibres. The description of a plan for future work in this area concludes this report. Further details are given in a page report Novel approaches alleviation of electrical hazards graphite-fibre composites by
52 for of K.
Ramohalli, Reference C37/N8016100 available as microfiche £1.61 (including VAT) or paper-copy £5.00.
Increased fracture toughness of graphite fibre-reinforced epoxy composites The increase of the fracture toughness of multi-layer continuousfilament graphite fibre-reinforced epoxy composites was studied. The method used was intermittent interlaminar bonding, which can lead to a large increase in the fracture surface area. Intermittent bonding was achieved by the introduction of thin perforated Mylar between the layers of the composite. Under the best test conditions, fracture toughness was increased from about 100 kJ/m = for untreated specimens to an average of 500 kJ/m =, while tensile strength dropped from 500 MPa to 400 MPa, and the elastic modulus remained the same (75 GPa). An approximate analysis is presented to explain the observed improvement in toughness. Further details are given in a 40 page report: Increased fracturetoughness of graphite-epoxy composites through intermittent i n t e r l a m i n a r b o n d i n g by D.K. Felbeck and J. Li-Chung, Reference C38/N80-1606 available as microfiche £1.61 (including VAT) or paper-copy £3.50. Polycrystalline whiskers High strength steel whiskers can be produced by decomposing iron pentacarbonyl in the presence of a homogeneous magnetic field. Their ultimate tensile stress has been determined to be as high as 6 GPa and values up to 8 GPa have been reported in the literature. In contrast to single crystal whiskers, their strength does not depend on diameter in the range between 5/Jm and 30/Jm. Steel whiskers are poly-
COMPOSITES . APR I L 1981
news crystalline with grain sizes from 5 nm to 30 nm. They can be produced with diameters ranging from a few thousand angstroms to more than 100 microns. With lengths from a few millimeters to ten millimeters, their aspect ratio can be varied from 100 to 10 000. During and after whisker growth their surfaces can be affected so as to exhibit predetermined compositions as w e l l as given t o p o g r a p h i e s which provide for the desired chemical bonding or degrees of mechanical bond strength at interfaces in composites. Whisker strength at elevated temperatures can be improved through alloying. The combination of a number of important properties together with the prospect of low production costs make polycrystalline steel whiskers potentially a unique material for structural and nonstructural composites.
Further details are given in a 26page report: Polycrystalline whiskers and their potential for fibre composites by H.G.F. Wilsdord, Reference C36/Ad-A080 320 available as microfiche £1.61 (inc VAT) or paper-copy £3.50.
Moisture effects on carbon fibre-reinforced composites An investigation was carried out to v e r i f y a s c h e m e p r o p o s e d in p r e v i o u s reports, w h i c h w o u l d make it possible to predict the reversible property changes in fibrereinforced structural materials under outdoor and service environments. Although the work was carried out specifically on a Hercules 3 5 0 1 - 6 / A s c a r b o n f i b r e reinforced epoxy composite, it is expected that it would apply for other organic matrix composites if the necessary consituent material data of the fibres and resins were
available and as long as a reasonably good matrix-to-fibre interfacial bonding could be assumed. It was shown that there is excellent agreement between the reversible property changes, caused by moisture uptake, as predicted by micromechanical methods and those experimentally observed. It was therefore concluded that, by applying simultaneously the concepts of moisture diffusion, environmental modelling, micromechanics, and a finite difference (or finite element) laminate theory, the reversible property changes in a composite as a function of time and as a function of the environment can be predicted. Further details are given in a 49 page report: Prediction and verification o f moisture effects on carbon fibre-epoxy composites by J.M. Augl, Reference C39/AD-A079 557 available as microfiche £1.61 (including VAT) or paper copy £3.50.
Errata It is regretted that a number of typographical errors were printed in the paper entitled 'Elastic behaviour of unidirectional short fibre reinforced thermoplastics' by F. Ramsteiner which was published in the January 1981 issue of Composites pp 65-71. Corrections are printed below: page 66, column 2 line 3 should read " . . . that of DIN 53457) . . . . . " page 67, column 2, final paragraph line 7 should read " . . . (at least below 20 volume % fibre concentration," page 69, column 2 line 2 should read "Level 2 e2 =
E~
page 70, column 1 line 14 should read " . . . and Equation (8):"
of Fig. 7
page 70, column 2 line 4 should read " . . . (constant) fibre aspect"
and the Equation (10) should read "G23 =
Figures
Gm
Fig. 8
'y' - axis is E R (N/mm 2)
Fig. 9
The author wishes to add to the legend - "(-30°C: = 0.72, Em = 4000 N/ram2; 70°C: /3 = 0.59, Em = 3600 N/mm2) ''
Fig. 10 The author wishes to add to the legend - " ( - 3 0 ° C : /3 = 0.6, Em = 4000 N/mm2) ''
Equations slEf + (m - s) IEm
COMPOSITES. APRI L 1981
11(EflEm - I + 11%/vf) + (I - ~/vf)
Equation
(8)
should
read
"E 2 =
1/(Gf/Gm -- 1 + 1/~/vf) + (1 -- ~/vf) References Reference 4 should read "Knibbs, R.H. and Morris, J.B . . . . . . . . . " Reference 16 should read " . . . . . . . . Kunststoffe 63 . . . . . . . "
Apologies are due to the author for these errors and omissions; and to readers for any confusion caused.
99
90
oss the inside of the frame (as shown in Fig. 1). The whole process of production is directly applicable to large scale production. It is also expected that the process will have applications in other areas of industry where strong, light-weight, accurate, and complicated mouldings are needed.
Fig. 1 The hollow frame of the Max 150G, showing internal support columns and reinforced stringing holes around the head
tion mould. The second, was the incorporation of strengthening pillars into the hollow structure at the exact positions where the high string tensions are applied to the frame. This was achieved by arranging holes in the core to coincide with the special pins (which were slightly smaller in diameter than the holes in the core) thus allowing the flow of thermoplastic material to create hollow support columns acr-
Further details from: Dunlop Limited, 10-12 King Street, St. James's, London SWIY 6RA, England.
Long-lasting 'You cannot put an old head on young shoulders' but you can put an old truck body on a new chassis and this is what has happened to the 14 ft (4.27 m) container shown in Fig. 3. Used for carrying spare components to BBC transmitting stations (often in very remote areas) all over Great Britain, the container had already travelled over
Fig. 2 Vibration damping studies on the finished racket, The ball is fired from a compressedair gun at the suspendedracketand the vibration trace is electronicallydisplayed
COMPOSITES . APR I L 1981
newsl 100 000 miles (161 x 10~ km) as the body on a Dodge RGO8 chassis. It has now been transferred (together with its original tail-lift) to a new RG09, G8685 model chassis which incorporates an extra large fuel tank, to continue its duties; thus proving suitability and durability of the 'Glasonit' - - w o v e n roving glass fibre-reinforced plastic manufactured by Technical Panel Industries Limited - - material from which the container is made.
strength is given as 235 J/m and compares favourably with values of 71 J/m for 'standard' grades. This, it is claimed, has been achieved with only minor reductions in strength and stiffness. 'Zytel' 80G-33 has been heat stabilized for use at elevated temperatures and in paint ovens and is expected to be used for wheels, chain saw housings, heavy duty engine fans, sporting goods, and under-the-bonnet automotive components.
Full details of 'Glasonit' grp panels are available from: Technical Panel Industries Limited, 4 Hollands Road, Industrial Estate, Haverhill, Suffolk, CB9 9LH, England.
'Zytel' FE 8018, containing 14% glass fibre reinforcement, has been developed for applications that require toughness but not the high stiffness of 'Zytel' 80G-33.
Tough and even tougher A 'super-tough' grade of glass fibre-reinforced nylon (containing 33% glass fibres) designated 'Zytel 80G-33 ', has been developed by the Du Pont Company. The Izod impact
'Zytel' 80G-33 is available in neutral colour only but a black grade is under development, as also is a grade containing 43% glass fibres. Further information from: Du Pont de Nemours International S.A., PO Box Ch-1210 Geneva 24, Switzerland.
The front panel of a train which will run on the Brussels Metro (claimed to be one of the most modern transport services in Europe) made from BP Chemicals Cellobond glass fibre-reinforced polyester resin. Being light in weight the use of grp panels gives a cost saving in terms of energy. The grp panels also have good weathering ability; some units have already been in operation for up to four years and have retained a good appearance, indicating a further saving on maintenance and cleaning. For further information on Cellobond polyester resins: BP Chemicals Limited, Speciality Plastics Division, Barry Factory, Sully, Penarth, South Glamorgan CF6 2YU, South Wales.
No guide lines
Fig. 3 The new transit van for specialized components needed by transmitting stations comprising the well-worn container on a new chassis
COMPOSITES. APRI L 1981
Trend Machinery and Cutting tools have introduced a new type of self-guiding trimming cutter for plastic laminates. The Trend 46/2 SG is claimed to trim faster than conventional cutters and can be used by semi-skilled labour. Dispensing with the need for fitting standard guides, the cutter maintains an accurate course by means
91
news of a roller bearing, mounted on the cutter base, which follows the edge of the underlying board. The cutting edge of the Trend 46/2 SG is at 90 ° but similar cutters with cutting edges at 80 °, 60 °, 45 °, and 30 ° can be obtained.
Trend Machinery and Cutting Tools Ltd, Unit N, Penfold Works, Imperial Way, Watford, Herts, WD2 4YY, England. To t r a n s m i t the load A reinforcement of 2 0 - 5 0 % a l u m i n i u m in an ultra high molecular weight polyethylene has been found to improve its modulus of elasticity, its c o m p r e s s i v e strength, and its thermal conductivity. Sheets of such a material have been produced by Solidur Plastics Limited and can be obtained in differing compositions and qualities. The material is claimed to be ideal for load transmission applications where high impact strength is required and has been successfully used as a buffer behind the chuck of a steel pile-driving-cap. Many other uses in engineering industries are envisaged for this material.
Fig. 4 A recently-built exhibition centre in Kent, England, showing the exterior roof cladding panels madefrom Telacor,an aluminium/polyethylene composite material
exhibition centre are made from white Telacor and the internal roof decking is made from Telatherm 900 which comprises 'Korrugal' metal skins bonded to a polyurethane core.
Further information from: Solidur Plastics Limited, Maybrook Road, Brownhills, Walsall, WS8 7DG, England.
Further details from: Teal Claddings Limited, Halesfield Industrial Estate, Telford, Shropshire, England.
Roof decking
Glass fillings
The exterior beige-coloured fascia panels on the roofing of an exhibition centre (Fig. 4) at Hempstead, Kent, England have been made from Telacoran aluminium polyethylene composite material, supplied by Teal Claddings Limited. The panels conceal the substantial guttering systems, specially designed to disperse water from the large roof expanse. The light-weight and low cost panels are claimed to have very flat surfaces that encourage an effective self-cleansing action. Interior fascia panels within the
The following products, which can be used for reinforcements in plastic materials, have been introduced onto the market by TBA Industrial Products Limited:
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MAT. 79, an emulsion bound chopped strand mat, produced from a fine, high integrity strand and made to a very tightly controlled mass/ unit area specification is intended to assist moulders to achieve consistent-weight mouldings. Its open structure affords rapid resin penetration and air release. MAT. 79 meets the requirements of BS
3496: 1973 and is approved by Lloyd's Register of Shipping for craft constructed under their survey, and by Dot Norske Veritas. ECR 1668 and ECR 1677 are filament winding rovings suitable for use on all proprietary and custombuilt filament winding machines. The dressing used on these rovings gives rapid resin penetration and fast wet-out; it contains a silane coupling agent which ensures compatability with orthophthalic, isophthalic, and bisphenol polyester resins and also with vinyl ester and epoxide resins. Further details from: TBA Industrial Products Limited, PO Box 40, Rochdale, Lancs, OL 12 7EQ, England. Satellite shielding A composite sandwich material with the highly specialized function of protecting space satellites from damage caused by high energy
COMPOSITES . APR I L 1981
news Preview The following is a preview of some forthcoming events, arranged in chronological order, Further details can be obtained from the addresses given at the end of each item, A comprehensive list of future meetings relating to composite materials can be found in the Calendar section.
The following short courses are being arranged at various university locations during the year: At the UCLA, Los Angeles, USA,
Materials aspects of damage tolerance, to be held on 6-10 April 1981,
Sea Falcon, Robin Knox-Johnson's new 70 ft (21.3m) ocean-racing catamaran, launched on 25 October 1980, at Brightlingsea, England, was built with BP Chemicals Cellobond glass fibre-reinforced polyester marine resins, a plywood box girder centre beam, and aluminium for and aft beams; the whole structure weighing 8.5 tonnes. The vessel has been entered for The Observer two-handed transatlantic race this year and Knox-Johnston is hoping to reclaim this and many other trophies for Britain with the Sea Falcon. BP Chemicals Limited, Be/grave House, 76 Buckingham Palace Road, London SW1W OSU, England.
electron bombardment has been developed and successfully tested by the Dynamics Group of British Aerospace. The material is made from Kapton (or Teflon) sandwiched between two layers of a very conductive material - - either aluminium or carbon - - with a very thin layer of Kapton on top. Electrically conductive paint around the edges of the material allows the conductive layers to be earthed to the main structure of the satellite. The purpose of the composite is to dissipate a surface charge the moment it encounters the spacecraft without allowing it to build up. Electrons penetrating the ultra-thin outer
COMPOSITES . APRI L 1981
Kapton skin are captured by the conducting layer and conducted away to the spacecraft structure; similarly, very energetic charged particles are captured by the innermost conductive layer. This material has been so devised that it will inhibit the build-up of high voltage charges without reducing the thermo-optical protective properties of the material to any significant extent. Further information from: British Aerospace Dynamics Group, Space and Communications Division, Gunnels Wood Road, Stevenage, Herts, SG1 2AS, England.
is intended for designers, manufacturers and users of all kinds of structural and constructional materials. It will concentrate on the aerospace, automotive, and energy production industries, considering how best to use the basic concepts of fracture mechanics to avoid both failures and overdesign of structural and constructional components and thereby to achieve savings in material, operating, and failure costs. Design-
ing with structural fibrous composites, to be held on 13-17 April 1981, will cover both the materials and structural aspects of composites. The purpose of the course is to impart a basic understanding of the properties and behaviour of loadbearing fibrous composites. Manufacture and design problems and also techniques where no codes of practice are available, will be discussed. Details of both courses can be obtained from: Continuing Education in
Engineering and Mathematics, UCLA Extension, PO Box 24901, Los Angeles, CA 90024, USA. At The U n i v e r s i t y of Surrey, Guildford, England, The technology
of fibre-reinforced plastics composite materials, to be held on 13-16 July 1981, is described as an intens-
93
lnews ive course for engineers, materials scientists and chemists concerned with fibre-reinforced plastic materials, particularly in the aerospace, automotive, marine and general engineering industries. It aims to relate the service performance of polymeric-matrix composites to their constitution and to the processing variables. The emphasis will be on practical systems of relevance to the various markets. The course will span matrix chemistry, curing, fabrication, testing and service performance as well as a review of the basic principles of reinforcement in both continuous and discontinuous fibre systems. Such areas as: short term properties of frp; properties of
matrices (resins), fibres and interfaces; long term properties - - creep, fatigue, durability and toughness; short-fibre moulded materials; the selection and fabrication of composites in relation to performance requirements; testing and evaluation of composite materials; and durability of grp in aggressive environments; will be covered. Full details are available from: Mr. M.G. Bader, Department of Metallurgy and Materials Technology, University of Surrey, Guildford, GU2 5XH, Surrey, England. At The University of Cambridge, England, Designing with fibrous
StPandGlassfibre
composites, will be held on 6-11 September, 1981. The course will take place at The Department of Engineering with accommodation at Peterhouse College and is intended to bring together materials scientists, designers, engineers, fabricators, and end users concerned with the design, manufacture, evaluation and use of fibre-reinforced structures and products. It will cover both materials and structural aspects of composites. Design problems and procedures will be examined, especially in cases where no codes of practice are available. Focus of attention will be on the properties and behaviour of load-bearing composites. The titles of lectures
Welding and Metal Fabrication
nowdeliHng
anew balsacore
material... lite.I We've extended our range of formers and core materials even more to include Corelite - end-grain, kilndried balsa blocks laminated to a glassfibre scrim. It is supplied in 48" x 18" sheets with standard thicknesses of3/g' ~/2;'s/g,and 3/~,making it easier to handle with less wastage in trimming.The blocks are only 1" square, so the material conforms easily to difficult mould contours and helps to eliminate voids. T h e consistent density and Lloyds approval also assures the manufacturer of a stable product to meet design and strength specifications. Corelite is available from our local branches throughout the country. For more information, contact our H e a d Office on 01-568 7191 or telex your order on 8951065.
GUIDE 81 U p d a t e d and e x p a n d e d for 1 9 8 1
Comprehensive listings of: • Metal fabricators • Metal stockholders • Services and equipment sources PRICE O N L Y £ 1 0 Further details from: The Editor, Welding and Metal Fabrication, PO Box 63, Westbun/House, Bun/Street, Guildford, Surrey GU2 5BH England Telephone: 0483 31261
Telex 859556 Scitec G
Brentway Trading Estate, Brenfford, Middlesex T W 8 8ER.
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COMPOSITES . APR I L 1981
newsl will include: mechanical properties, test methods, data acquisition and analysis; manufacturing methods, processing and quality assurance; structural applications n design methods and design configurations; environmental induced degradation; non-destructive evaluation; reliability and damage tolerance; and failure analysis, fracture toughness, and micromechanisms of crack extension. Further details from: Dr P.W.R. Beaumont, Fracture Analysis International Ltd, East England Office, Westwood House, Dukes Meadow Stapleford, Cambridge, CB2 5BH, England. At The U n i v e r s i t y of Bristol, England, Materials aspects of damage tolerance, to be held on 14-18 September 1981 will examine how fracture mechanics concepts can be used to overcome failures and overdesign of structural and constructional components thereby making savings in costs. Engineering materials to be examined will include metals, ceramics, glass and composites. The course is intended for holders of a science or engineering degree or those with a wide experience in materials technology. Subjects to be covered will include: concept of damage tolerance; ceramics, and other materials when exhibiting brittle behaviour; metals, including welds; adhesives and adhesive joints; polymers and composite materials. Further details from: Dr K.H.G. Ashbee, Fracture Analysis International Ltd, West England Office, 2 Druid Stoke Avenue, Stoke Bishop, Bristol, BS9 1DD, England. The second international symposium on Energy and composite materials is due to be held in Venice, Italy, 3, 4 and 5 June 1981. Organized j o i n t l y by I n s t i t u t
COMPOSITES. APR I L 1981
Francais du Petrole, Amoco Chemicals Europe, and Owens Corning Fiberglas Europe, the symposium will comprise 50 lecturers and also a poster session on the energy content of composite materials and their uses in: traditional energy applications; alternative energy applications; and transportation. Further information can be obtained from: G~rard Bonavent, Institut Fran£ais du Petrole, 1 et 4 avenue de Bois-Preau, B.P. 311, 92506 Rueil Malmaison, France. An i n t e r n a t i o n a l c o l l o q u i u m arranged by the CNRS on Plastic behaviour of anisotropic solids is due to take place in Grenoble, France, on 15-19 June 1981. It is intended to specialize in the study of the mechanical behaviour at large plastic deformation of solids which have either initial anisotropy or 'induced' anisotropy (caused by deformation, hardening, damage etc). It intends to bring together the study of macroscopic phenomenological behaviour using continuum mechanics and the study of the directional properties of the internal structure and by so doing, improve the mathematical modelling of anistropic solids, such as composite materials, metals, soils and rocks. There is a call for papers in such areas as: formulation of constitutive laws at large irreversible deformations within non-linear continuum mechanics; correlations between the material oriented structure and the directional character of the appearance and growth of cracks, voids and discontinuity lines; correct interpretation of 'off-axis' tests up to damage and failure; influence of the loading path under complex stresses; homogenization of the material with internal oriented structure; numerical formulation for anistropic materials at large deformations; and experiments on the
behaviour of structures. Participation in the colloquium will be by invitation. Interested authors are requested to send a summary (800-1000 words) by 30 March 1981 to: M.J.P. Boehler, Institut de Mechanique (IMG), B.P. 53 X, 38041 Grenoble Cedex, France. An International conference on the science of hard materials is to be held at Jackson Lake Lodge, Wyoming, USA, on 23-28 August 1981. This is described as an in-depth conference which will consider the fundemental physical and chemical properties of hard materials, particularly transition metal carbides, borides, and nitrides and their influence on the mechanical behaviour and structure/property relationships in hard metal composites. The application of the most recent analytical methods to the study of hard materials will be appraised. Main topics for consideration will be: fundamental properties, microstructure, mechanical behaviour, surface treatments, and new horizons. F u r t h e r d e t a i l s f r o m : R.K.V. Viswanadham, Materials Research, Reed Rock Bit, Houston, Texas 77001, USA. The sixth biennial plastics seminar on Managing corrosion with plastics is scheduled to take place at the Peachtree Plaza Hotel, Atlanta, Georgia, USA on 26-29 October 1981. Further information from: The National Association of Corrosion Engineers, PO Box 218340, Houston Texas 77218, USA. A two-day seminar organized jointly by The Fillers and Reinforcing Agents Section of the Additives Group of the British Plastics Federation and The Department of NonMetallic Materials, Brunel Univer-
95
lnews sity, on The growth in the use of fillers in plastics is planned to take place in the first week of November 1981, in London, England. It is intended that the first day will be concerned with general aspects, such as economy, energy saving advantages of incorporating fillers, and various types of fillers. The second day will be devoted to four application areas: packaging; automotives; domestic applicances; and pipes. The seminar will be aimed specifically at the end-user. There is a call for papers and brief synopses should be sent: Mr S.M.L. Brown,
The British Plastics Federation, 5 Belgrave Square, London SWIX 8PH, England. Further details can also be obtained from the same adress. There is also a call for papers for a conference entitled: Automotive Manufacturing - Update 81. The conference, organized by The Automobile Division of the Institution of Mechanical Engineers is due to take place at their headquarters in London on 1-2 December 1981. Contributions are invited on specific areas of relevance such as: new materials in production of vehicles eg to meet anti-corrosion and safety legislation, and to reduce weight, manufacturing, and wholelife costs, and energy considerations in manufacture. Abstracts (250 words) are to be sent to: Peter Thomas, Secretary, Auto-
mobile Division, The Institution of Mechanical Engineers, I Birdcage Walk, Westminster, London SWTH 9JJ, England, from whom further details can be obtained. on Jointing in fibre-reinforced plastics, arranged by The Department of Aeronautics, Imperial College, in collaboration with The Royal Aircraft Establishment (previously announced for 6, 7 June 1982) is now scheduled to The symposium
96
take place on 13, 14 July 1982 at The Imperial College of Science and Technology, London. The aim of the symposium is to bring together workers in the composite materials field, from industry, and from academic and research establishments. It is hoped to cover the four main areas: design; application; testing; and theory. Adhesively bonded joints, bolted and riveted joints, and composite to composite joints will be discussed for all types of fibre-reinforced plastics including: carbon and glass in epoxy; glass in polyester; chopped strand mat and woven roving in polyester; and smc. Such effects as static and fatigue behaviour, failure modes, in-service and environmental effects, and repairs will also be considered. Sponsors of the meeting will include: Carr R e i n f o r c e m e n t s ; Ciba-Geigy; Courtaulds Carbon Fibres Division; and BTR Permali. There is a call for papers and authors wising to participate are invited to send an abstract (200 words) of their proposed paper before 30 September 1981. The papers will be classified as short (5 to 10 min) or long (20 min) and authors are requested to make it clear into which category their paper fits. Authors will be notified by mid-November 1981 if their paper has been accepted; final drafts will be requested by the end of February 1982. Abstracts should be sent to: Mr F.L. Matthews, Aeronautics Department, Imperial College of Science and Technology, London SW7 2BY, England. A conference with the expressed i n t e n t i o n of ' p r o m o t i n g keen discussion, through the use of controversial arguments where necessary' is being planned by The Plastics and Rubber Institute. The conference will be on the subject of The
further use of plastics in the auto-
motive industry and it is intended it will take place about two weeks before the UK Motor Show in October 1982. The subjects to be covered will include: materials developments; processing developments; new components design study where a major item is a plastics moulding; design trends which could influence the choice of - - or even the rejection" of - - plastics parts. Papers on any of the above subjects are being called for and a synopsis (250 words) should be sent by 31 March 1981. A feature of the conference is expected to be a 'design comparison' exercise based on a hypothetical fascia panel. Offers of papers should be sent to:
Mrs Trish Munday, The Plastics and Rubber Institute, 11 Hobart Place, London SW1W OHL, England.
Publications Books for buying Two new publications resulting from a symposium and a conference both held in Los Angeles, USA, in December 1980 and organized by Technology Conferences (the conference, in conjuction with the south California section of the Society of Plastics Engineers) are now available.
Kevlar Composites is a collection of papers presented at a special symposium of the same name. The subjects covered are the development and use of Kevlar aramid fibre-reinforced plastics/composites for a wide range of applications including: aircraft; helicopters; spacecraft; automotives; sporting goods; pressure vessels; etc; together with a section on machining technology for Kevlar composites. The book costs $24.00.
COMPOSITES . APR I L 1981
news Reinforced plastics covers a wide spectrum of current reinforced plastics technology (including materials, processing, applications). It includes a special section by W. Brandt Goldsworthy on Economic advantages of RP/C in high volume applications, and a special feature on the evolution and development of the Windecker 'Eagle' (claimed to be the first successful reinforced plastic airframe structure). The book of the papers from the conference costs $26.00. Both
books are available from: Technology Conferences, PO Box 842, E1 Segundo, CA 90245, USA. The prices given are for the USA, $3.00 should be added for each book by sea mail or $10.00 for air mail. A hand book entitled: A guide to high performance plastics composites provides information for engineers and potential end-users on composites materials containing 50% or more of high modulus fibres. There are sections on the nature of these materials and also manufacturing methods, test methods, and design approaches. Examples of the design of a carbon fibre reinforced drive shaft for a commercial car and a portable lifting frame are cited. There is a glossary section and data sheets for 20 such composites. The book costs £12.50 (£8.00 for BPF members) and is available from: The British Plastics Federa-
tion, 5 Belgrave Square, London SWlX 8PH, England.
Books for free Two new buyer's guides have been announced by The British Plastics Federation. The British Plastics Fed-
eration Buyer's guide for laminated plastics fabrication is issued by the British Laminated Plastics Fabricators Association and provides useful
COMPOSITES . APR I L 1981
information of high pressure decorative laminates to a variety of core materials thus producing hardwearing surfaces used in furniture and fittings. The Guide provides an alphabetical list of members and details of associate members providing services. The British Plastics Federation Buyer's Guide for Plastics Solar Heating Systems and Components contains a chart of suppliers and their products and a list of member companies and affiliates. The BPF also reminds that the following guides have already been issued: Moulded Products and Ser-
vices: Plastics Additives; Thermoplastics Polymers; Compounds and Masterbatches; and Plastics Processing Machinery and Equipment. The BPF also has produced a leaflet entitled: Plastics for the Engineer. This lists the properties of plastics for engineering use, notes on the varieties of each available plastics material, and information on the processes used for producing engineering components. The Guides and leaflet are available from: The British Plastics Federa-
tion, 5 Be/grave Square, London SWIX 8PH, England. Contact moulding by spray deposition is the title of a brochure published by The Glass Fibre Division of TBA Industrial Products Ltd which has recently been revised and brought up to date. The brochure describes all aspects of spray deposition and lists the advantages and disadvantages of the process. It also compares the costs of producing identical mouldings by the spray deposition and hand lay-up techniques. The brochure
is available from:
TBA Industrial Products Ltd, PO Box 40, Rochdale, Lancs, 0L12 7EQ, England.
Lloyd's Register Industrial Services provides an international independant technical and advisory inspection service for all types of industrial plant and machinery. A booklet entitled Lloyd's Register Industrial Services shows the wide areas (both geographical and industrial) over which these services are available. It is available from: The Secretary, Lloyd's Register Industrial Services, Norfolk House, Croydon, CR9 2DT, England. The Industrial Textiles Division of Fothergill and Harvey Ltd has recently issued a brochure entitled:
Woven materials for plastics reinforcement (from glass, carbon, aramid and polyester fibres). Topics covered in the brochure include: fibres for plastics reinforcement, the advantage of woven reinforcements, weave characteristics, fabric finishes, resin compatibility, and hybrid reinforcements. Another section gives e x a m p l e s of how Fothergill and Harvey reinforcements have been used in laminates for aerospace equipment, medical apparatus, ships, building materials, and sporting goods. Copies of the brochure are available from: Fothergill and Harvey Ltd,
Industrial Textiles Division, Summit, Littleborough, Lancs, 0115 9QP, England. Specially prepared to meet the need for greater design data standardization the Performance Plastics Group of ICI Plastics Division has produced six new-style technical data sheets on Maranyl nylon 66 materials. Of these N TD 54 deals specifically with Maranyl glass rein-
forced nylon 66. These are available from: ICI Plastics Division, Welwyn Garden City, Herts, AL7 IHD, England.
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nlrrl=CU
news In touch with TechAlert Over 50 000 reports of publicly-funded research projects are received annually by the Technology Reports Centre in the UK; the majority come from the USA, although the network is worldwide. These reports generally remain unpublished, or are difficult to obtain from source. Summaries of reports likely to be of interest to readers of Composites are now regularly prepared by the Centre and will be included in the News Section in each issue. Full copies of the original reports are available from: TechAlert, Technology Reports Centre, Orpington, Kent, SR5 3RF. The title and reference number given at the end of each item should be quoted with all orders.
Fire tests method for graphite fibre-reinforced plastics A potential problem in the use of graphite fibre-reinforced resin matrix composites is the dispersal of graphite fibres during accidental fires. Air-borne, electrically conductive fibres originating from the burning composites could enter and cause shorting in electrical equipment located in surrounding areas. A test method for assessing the burning characteristics of graphite fibre-reinforced composites and the effectiveness of the composites in retaining the graphite fibres has been developed. The method utilizes a modified Ohio State University Rate of Heat Release apparatus. The equipment and the testing procedure are described. The application of the test method to the assessment of composite materials is illustrated for two resin matrix/graphite composite systems. Further details are given in a 11 page report: Fire test method for graphite fibre-reinforced plastics by
K.J. Bowles, Reference C35/N801807 available as microfiche £1.61 (includiing £2.00.
VAT) or paper-copy
The alleviation of electrical hazards This study was aimed at exploring the feasibility of different approaches to solve the electrical problems posed by graphite fibre-reinforced composites. Four basically different
98
approaches were considered: gasification of fibres, retention in the matrix, clumping to prevent entrainment, and electrical insulation of fibres. The techniques used to achieve them are described in some detail. These involved surface treatment of fibres to improve the wettability of fibres and coating the fibres with the selected substances before laying them up for composite fabrication. Thermogravimetric analyses were performed on the plain and treated fibres in inert (nitrogen, argon) and reactive (air) atmospheres. The treated fibres embedded in epoxy were ignited in a Bunsen flame to determine the efficiency of these treatments. A simple apparatus was assembled to detect the time for the first short circuit (in a typical electrical circuit) when exposed to the combustion products from a graphite fibre composite fire. The state-of-the-art and treated fibres cast in typical epoxy were burned and ranked for potential success. It was inferred that the gasification schemes appear promising when reduction or oxidation is tried. It was also found that some very promising candidates were available for the clumping and for the electrical insulation of fibres. The description of a plan for future work in this area concludes this report. Further details are given in a page report Novel approaches alleviation of electrical hazards graphite-fibre composites by
52 for of K.
Ramohalli, Reference C37/N8016100 available as microfiche £1.61 (including VAT) or paper-copy £5.00.
Increased fracture toughness of graphite fibre-reinforced epoxy composites The increase of the fracture toughness of multi-layer continuousfilament graphite fibre-reinforced epoxy composites was studied. The method used was intermittent interlaminar bonding, which can lead to a large increase in the fracture surface area. Intermittent bonding was achieved by the introduction of thin perforated Mylar between the layers of the composite. Under the best test conditions, fracture toughness was increased from about 100 kJ/m = for untreated specimens to an average of 500 kJ/m =, while tensile strength dropped from 500 MPa to 400 MPa, and the elastic modulus remained the same (75 GPa). An approximate analysis is presented to explain the observed improvement in toughness. Further details are given in a 40 page report: Increased fracturetoughness of graphite-epoxy composites through intermittent i n t e r l a m i n a r b o n d i n g by D.K. Felbeck and J. Li-Chung, Reference C38/N80-1606 available as microfiche £1.61 (including VAT) or paper-copy £3.50. Polycrystalline whiskers High strength steel whiskers can be produced by decomposing iron pentacarbonyl in the presence of a homogeneous magnetic field. Their ultimate tensile stress has been determined to be as high as 6 GPa and values up to 8 GPa have been reported in the literature. In contrast to single crystal whiskers, their strength does not depend on diameter in the range between 5/Jm and 30/Jm. Steel whiskers are poly-
COMPOSITES . APR I L 1981
news crystalline with grain sizes from 5 nm to 30 nm. They can be produced with diameters ranging from a few thousand angstroms to more than 100 microns. With lengths from a few millimeters to ten millimeters, their aspect ratio can be varied from 100 to 10 000. During and after whisker growth their surfaces can be affected so as to exhibit predetermined compositions as w e l l as given t o p o g r a p h i e s which provide for the desired chemical bonding or degrees of mechanical bond strength at interfaces in composites. Whisker strength at elevated temperatures can be improved through alloying. The combination of a number of important properties together with the prospect of low production costs make polycrystalline steel whiskers potentially a unique material for structural and nonstructural composites.
Further details are given in a 26page report: Polycrystalline whiskers and their potential for fibre composites by H.G.F. Wilsdord, Reference C36/Ad-A080 320 available as microfiche £1.61 (inc VAT) or paper-copy £3.50.
Moisture effects on carbon fibre-reinforced composites An investigation was carried out to v e r i f y a s c h e m e p r o p o s e d in p r e v i o u s reports, w h i c h w o u l d make it possible to predict the reversible property changes in fibrereinforced structural materials under outdoor and service environments. Although the work was carried out specifically on a Hercules 3 5 0 1 - 6 / A s c a r b o n f i b r e reinforced epoxy composite, it is expected that it would apply for other organic matrix composites if the necessary consituent material data of the fibres and resins were
available and as long as a reasonably good matrix-to-fibre interfacial bonding could be assumed. It was shown that there is excellent agreement between the reversible property changes, caused by moisture uptake, as predicted by micromechanical methods and those experimentally observed. It was therefore concluded that, by applying simultaneously the concepts of moisture diffusion, environmental modelling, micromechanics, and a finite difference (or finite element) laminate theory, the reversible property changes in a composite as a function of time and as a function of the environment can be predicted. Further details are given in a 49 page report: Prediction and verification o f moisture effects on carbon fibre-epoxy composites by J.M. Augl, Reference C39/AD-A079 557 available as microfiche £1.61 (including VAT) or paper copy £3.50.
Errata It is regretted that a number of typographical errors were printed in the paper entitled 'Elastic behaviour of unidirectional short fibre reinforced thermoplastics' by F. Ramsteiner which was published in the January 1981 issue of Composites pp 65-71. Corrections are printed below: page 66, column 2 line 3 should read " . . . that of DIN 53457) . . . . . " page 67, column 2, final paragraph line 7 should read " . . . (at least below 20 volume % fibre concentration," page 69, column 2 line 2 should read "Level 2 e2 =
E~
page 70, column 1 line 14 should read " . . . and Equation (8):"
of Fig. 7
page 70, column 2 line 4 should read " . . . (constant) fibre aspect"
and the Equation (10) should read "G23 =
Figures
Gm
Fig. 8
'y' - axis is E R (N/mm 2)
Fig. 9
The author wishes to add to the legend - "(-30°C: = 0.72, Em = 4000 N/ram2; 70°C: /3 = 0.59, Em = 3600 N/mm2) ''
Fig. 10 The author wishes to add to the legend - " ( - 3 0 ° C : /3 = 0.6, Em = 4000 N/mm2) ''
Equations slEf + (m - s) IEm
COMPOSITES. APRI L 1981
11(EflEm - I + 11%/vf) + (I - ~/vf)
Equation
(8)
should
read
"E 2 =
1/(Gf/Gm -- 1 + 1/~/vf) + (1 -- ~/vf) References Reference 4 should read "Knibbs, R.H. and Morris, J.B . . . . . . . . . " Reference 16 should read " . . . . . . . . Kunststoffe 63 . . . . . . . "
Apologies are due to the author for these errors and omissions; and to readers for any confusion caused.
99