Обучение чтению литературы на английском языке по специальности «Композиционные материалы»
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Тематика:
Английский язык
Год издания: 2012
Кол-во страниц: 36
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Учебно-методическая литература
Уровень образования:
ВО - Бакалавриат
Артикул: 840508.01.99
В методических указаниях представлены оригинальные тексты на английском языке, необходимые для аудиторной и самостоятельной работы студентов, обучающихся по специальности «Композиционные материалы», а также упражнения на развитие навыков устной речи, чтения и понимания научно-технической литературы на английском языке, на закрепление грамматического и лексического материала. Для студентов старших курсов факультета «Специальное машиностроение» МГТУ им. Н.Э, Баумана. Рекомендовано Учебно-методической комиссией НУК ФН МГТУ им. Н.Э. Баумана.
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Московский государственный технический университет имени Н.Э. Баумана Л.А. Кузьмина, А.В. Шашмурина ОБУЧЕНИЕ ЧТЕНИЮ ЛИТЕРАТУРЫ НА АНГЛИЙСКОМ ЯЗЫКЕ ПО СПЕЦИАЛЬНОСТИ «КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ» Методические указания М о с к в а Издательство МГТУ им. Н.Э. Баумана 2 0 1 2
УДК 802.0 ББК 81.2 Англ-923 К89 Рецензент И.В. Стасенко Кузьмина Л.А. Обучение чтению литературы на английском языке по специальности «Композиционные материалы» : метод. указания / Л.А. Кузьмина, А.В. Шашмурина. — М.: Изд-во МГТУ им. Н.Э. Баумана, 2012. — 32, [4] с. В методических указаниях представлены оригинальные тексты на английском языке, необходимые для аудиторной и самостоятельной работы студентов, обучающихся по специальности «Композиционные материалы», а также упражнения на развитие навыков устной речи, чтения и понимания научно-технической литературы на английском языке, на закрепление грамматического и лексического материала. Для студентов старших курсов факультета «Специальное машиностроение» МГТУ им. Н.Э, Баумана. Рекомендовано Учебно-методической комиссией НУК ФН МГТУ им. Н.Э. Баумана. УДК 802.0 ББК 81.2 Англ-923 © МГТУ им. Н.Э. Баумана, 2012 К89
ПРЕДИСЛОВИЕ В методических указаниях представлены оригинальные тексты, взятые из английских научно-технических изданий, необходимые для аудиторной и самостоятельной работы студентов старших курсов, обучающихся по специальности «Композиционные материалы». Методические указания состоят из трех блоков, включающих тексты для изучающего, просмотрового и поискового чтения, активную лексику, упражнения, направленные на закрепление лексико-грамматического материала. Предложены также тексты для письменного перевода как с английского языка на русский, так и с русского языка на английский, требующие последующего обсуждения трудностей перевода. Помимо этого представлены коммуникационные задания по основным проблемам, затронутым в методических указаниях. Целью работы является помощь студентам в освоении и развитии навыков чтения, перевода и коммуникации по специальности «Композиционные материалы».
UNIT I New Words and Word Combination align v — располагать по одной линии, выравнивать asset n — ценное, полезное свойство bend v — изгибать, гнуть binding power — связующая способность brittle adj — хрупкий bundle n — связка, пучок cure v — восстанавливать dissolve v — растворяться fracture toughness — вязкость разрушения, трещиностойкость irreversible adj — неизменяемый, необратимый mould n — форма, лекало, шаблон moulding process — процесс формовки pultrusion n — получение одноосноориентированного волокнистого пластика reinforcement n — усиление, упрочнение, армирование saturate v — пропитывать, насыщать share stress — распределять нагрузку snap v — разламывать stretch v — растягивать, вытягивать tailor properties — разрабатывать, проектировать свойства thermoplastic(s) — термопластмасса thermoset — реактопласт, термореактивная пластмасса thread n — нить timber n — древесина wear n — износ
1. Find the transcription of the following words in a dictionary. Pronounce them carefully: pultrusion, irreversible, thermoplastics, brittle, fiberglass, tension, moulding. 2. Translate the following words and word combinations: swimming pool linings, long fibres of cellulose, bundle of cotton fibres, reinforced concrete, tensile strength, thermosoftening plastics, bulletproof vests and helme. 3. Read and translate Text IA. Choose the proper titles to the parts of the text. A. Making a composite. B. Not a new idea. C. Choosing materials for the matrix. D. Selecting the materials for the reinforcement. E. What makes a material a composite? F. Manufacturing process. G. What are the reasons for selecting composite materials? Text IA In an advanced society like ours we all depend on composite materials in some aspect of our lives. Fibreglass, developed in the1940s, was the first modern composite and is still the most common. It makes up about 65 percent of all the composites produced today and is used for boat hulls, surfboards, sporting goods, swimming pool linings, building panels and car bodies. You may well be using something made of fiberglass without knowing it. 1 Composite materials are formed by combining two or more materials that have quite different properties. The different materials work together to give the composite unique properties,
but within the composite you can easily tell the different materials apart — they do not dissolve or blend into each other. Composites exist in nature. A piece of wood is a composite, with long fibres of cellulose (a very complex form of starch) held together by a much weaker substance called lignin. Cellulose is also found in cotton and linen, but it is the binding power of the lignin that makes a piece of timber much stronger than a bundle of cotton fibres. 2 Humans have been using composite materials for thousands of years. Take mud bricks for example. A cake of dried mud is easy to break by bending, which puts tension force on one edge, but makes good strong wall, where all the forces are compressive. A piece of straw, on the other hand, has a lot of strength when you try to stretch it but almost none when you crumple it up. But if you embed pieces of straw in a block of mud and let it dry hard, the resulting mud brick resists both squeezing and tearing and makes an excellent building material. Put more technically, it has both good compressive strength and good tensile strength. Another well-known composite is concrete. Here aggregate (small stones or gravel) is bound together by cement. Concrete has good strength under compression, and it can be made stronger under tension by adding metal rods, wires, mesh or cables to the composite (so creating reinforced concrete). 3 Most composites are made up of just two materials. One material (the matrix of binder) surrounds and binds together a cluster of fibres or fragments of a much stronger material (the reinforcement). In the case of mud bricks, the two roles are taken by the mud and the straw; in concrete, by the cement and the aggregate; in a piece of wood, by the cellulose and the lignin. In fiberglass, the reinforcement is provided by fine threads of fibres of glass, often woven into a sort of cloth, and the matrix is a plastic.
The threads of glass in fiberglass are very strong under tension but they are also brittle and will snap if bent sharply. The matrix not only holds the fibres together, it also protects them from damage by sharing any stress among them. The matrix is soft enough to be shaped with tools, and can be softened by suitable solvents to allow repairs to be made. Any deformation of a sheet of fiberglass necessarily stretches some of the glass fibres, and they are able to resist this, so even a thin sheet is very strong. It is also quite light, which is an advantage in many applications. Over recent decades many new composites have been developed, some with very valuable properties. By carefully choosing the reinforcement, the matrix, and the manufacturing process that brings them together, engineers can tailor the properties to meet specific requirements . They can, for example, make the composite sheet very strong in one direction by aligning the fibres that way, but weaker in another direction where strength is not so important. They can also select properties such as resistance to heat, chemicals, and weathering by choosing an appropriate matrix. For the matrix, many modern composites use thermosetting or thermosoftening plastics (also called resins). (The use of plastics in the matrix explains the name “reinforced plastics” commonly given to composites.) The plastics are polymers that hold the reinforcement together and help to determine the physical properties of the end product. Thermosetting plastics are liquid when prepared but harden and become rigid (i. e. they cure) when they are heated. The setting process is irreversible, so that these materials do not become soft under high temperatures. These plastics also resist wear and attack by chemicals making them very durable, even when exposed to extreme environments. Thermosoftening plastics, as the name implies, are hard at low temperatures but soften when they are heated. Although they are less commonly used than thermosetting plastics they do have
some advantages, such as greater fracture toughness, long shelf life of the row material, capacity for recycling and a cleaner, safer workplace because organic solvents are not needed for the hardening process. Ceramics, carbon and metals are used as the matrix for some highly specialized purposes. For example, ceramics are used when the material is going to be exposed to high temperatures (e. g. heat exchangers) and carbon is used for products that are exposed to friction and wear (e. g. bearings and gears). 4 Although glass fibres are by far the most common reinforcement, many advanced composites now use fine fibres of pure carbon. Carbon fibres are much stronger than glass fibres, but are also more expensive to produce. Carbon fibres composites are light as well as strong. They are used in aircraft structures and in sporting goods, and increasingly are used instead of metals to repair or replace damaged bones. Even stronger (and more costly) than carbon fibres are threads of boron. Polymers are not only used for the matrix, they also make a good reinforcement material in composites. For example, Kevlar is a polymer fibre that is immensely strong and adds toughness to a composite. It is used as the reinforcement in composite products that require lightweight and reliable construction (e. g. structural body parts of an aircraft). Composite materials were not the original use for Kevlar — it was developed to replace steel in radial tyres and is now used in bulletproof vests and helmets. 5 Making an object from a composite material usually involves some form of mould. The reinforcing material is first placed in the mould and semi-liquid matrix material is sprayed or pumped in to form the object. Pressure may be applied to force out any air bubbles, and the mould then heated to make the matrix.
The moulding process is often done by hand, but automatic processing by machines is becoming more common. One of the new methods is called pultrusion (a term derived from words “pull” and “extrusion”). This process is ideal for manufacturing products that are straight and have a constant cross section, such as bridge beams. In many thin structures with complex shapes, such as curved panels, the composite structure is built up by applying sheets of woven fibre reinforcement, saturated with the plastic matrix material, over an appropriately shaped base mould. When the panel has been built to an appropriate thickness, the matrix panel is then cured. In many advanced composites (such as those used in the wing and body panels of aircraft), the structure may consist of a honeycomb of plastic sandwiched between two skins of carbonfibre reinforced composite material. Such sandwich composites combine high strength, and particularly bending stiffness, with low weight. Like everything to do with aircraft, they can very costly! 6 The greatest advantage of composite materials is strength and stiffness combined with lightness. By choosing an appropriate combination of reinforcement and matrix material, manufacturers can produce properties that exactly fit the requirements for a particular structure for a particular purpose. Modern aviation, both military and civil, is a prime example. It would be much less efficient without composites. In fact, the demands made by that industry for materials that are both light and strong has been the main force driving the development of composites. It is common now to find wing and tail sections, propellers and rotor blades made from advanced composites, along with much of the internal structure and fittings. The airframes of some smaller aircraft are made entirely from composites, as are the wing, tail and body panels of large commercial aircraft.
7 In thinking about planes, it is worth remembering that composites are less likely than metals (such as aluminium) to break up completely under stress. A small crack in a piece of metal can spread very rapidly with very serious consequences (especially in the case of aircraft). The fibres in a composite act to block the widening of any small crack and to share the stress around. The right composites also stand up well to heat and corrosion. This makes them ideal for use in products that are exposed to extreme environments such as boats, chemical-handling equipment and spacecraft. In general, composite materials are very durable. Another advantage of composite materials is that they provide design flexibility. Composites can be moulded into complex shapes — a great asset when producing something like a surfboard or a boat hull. The downside of composites is usually the cost. Although the manufacturing processes are often more efficient when composites are used, the raw materials are expensive. Composites will never totally replace traditional materials like steel, but in many cases they are just what we need. And no doubt new uses will be found as the technology evolves. We haven’t yet seen all that composites can do. 4. Answer the questions to the text. 1. What materials do we call “composites”? 2. What were the first composite materials used by humans? 3. What matrix (reinforcement) materials can you name? 4. Where can composite materials be used? 5. What are the advantages of composites? 6. Name some valuable properties of composite materials.