I already posted this question 2rd time now someone didn\'t answer the whole thi
ID: 1710628 • Letter: I
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I already posted this question 2rd time now someone didn't answer the whole thing this is a 2rd refund please just answer all parts:
You are required to answer all parts of the question. Our professor gave it as you see it as a single question, so to save to getting a refund and posting again just please.
I know the rule is 1 question at a time in material science at our university this is a single question!!
And correctly clear writting please.
it would be a pain for me to separate them, since I have a fair bit of them.
And finally please do not write on a piece of paper then take a single photo with your mobile phone its going to be blured we can't see it use a photo copier. otherwise take multiple close up photos if mobile is all you have.
3. a) Summarise the different types of fibre reinforced composite material available in terms of reinforcement constitution, form, spacial distribution and relative proportion of components. (10 marks b) In terms of the above attributes, what would be the choice for obtaining the best performance composite for a structural application? (4 marks) c) Give four current manufacturing methods for producing continuous fibre composites. (4 marks) d) What are the main functions of the skins and the core in a sandwich composite? (2 marks)Explanation / Answer
A) Different typs of fiber reinforced composite materials
1)Glass fibre
"Fibreglass reinforced plastics" or FRPs (commonly referred to simply as fibreglass) use textile grade glass fibres. These textile fibres are different from other forms of glass fibres used to deliberately trap air, for insulating applications (see glass wool). Textile glass fibres begin as varying combinations of SiO2, Al2O3, B2O3, CaO, or MgO in powder form. These mixtures are then heated through direct melting to temperatures around 1300 degrees Celsius, after which dies are used to extrude filaments of glass fibre in diameter ranging from 9 to 17 µm. These filaments are then wound into larger threads and spun onto bobbins for transportation and further processing. Glass fibre is by far the most popular means to reinforce plastic and thus enjoys a wealth of production processes, some of which are applicable to aramid and carbon fibres as well owing to their shared fibrous qualities.
Roving is a process where filaments are spun into larger diameter threads. These threads are then commonly used for woven reinforcing glass fabrics and mats, and in spray applications.
Fibre fabrics are web-form fabric reinforcing material that has both warp and weft directions. Fibre mats are web-form non-woven mats of glass fibres. Mats are manufactured in cut dimensions with chopped fibres, or in continuous mats using continuous fibres. Chopped fibre glass is used in processes where lengths of glass threads are cut between 3 and 26 mm, threads are then used in plastics most commonly intended for moulding processes. Glass fibre short strands are short 0.2–0.3 mm strands of glass fibres that are used to reinforce thermoplastics most commonly for injection moulding.
2)Carbon fibre
Carbon fibres are created when polyacrylonitrile fibres (PAN), Pitch resins, or Rayon are carbonized (through oxidation and thermal pyrolysis) at high temperatures. Through further processes of graphitizing or stretching the fibres strength or elasticity can be enhanced respectively. Carbon fibres are manufactured in diameters analogous to glass fibres with diameters ranging from 4 to 17 µm. These fibres wound into larger threads for transportation and further production processes.[2] Further production processes include weaving or braiding into carbon fabrics, cloths and mats analogous to those described for glass that can then be used in actual reinforcements.[1]
3)Aramid fibre
Aramid fibres are most commonly known as Kevlar, Nomex and Technora. Aramids are generally prepared by the reaction between an amine group and a carboxylic acid halide group (aramid);[1] commonly this occurs when an aromatic polyamide is spun from a liquid concentration of sulphuric acid into a crystallized fibre.[2] Fibres are then spun into larger threads in order to weave into large ropes or woven fabrics (Aramid).[1] Aramid fibres are manufactured with varying grades to based on varying qualities for strength and rigidity, so that the material can be somewhat tailored to specific design needs concerns, such as cutting the tough material during manufacture
4)Inorganic particulates
It involves a composite material of Semicrystalline thermoplastics. By using this fibers some properties are improved such as Isotropic shrinkage, abrasion, compression strength etc.
5)Microspheres
microspheres are mainly used to reduce the weight of structure.
B)
High-performance fiber-reinforced cementitious composites (HPFRCCs) are a group of fiber-reinforced cement-based composites which possess the unique ability to flex and self-strengthen before fracturing. This particular class of concrete was developed with the goal of solving the structural problems inherent with today’s typical concrete, such as its tendency to fail in a brittle manner under excessive loading and its lack of long-term durability. Because of their design and composition, HPFRCCs possess the remarkable ability to strain harden under excessive loading. In layman’s terms, this means they have the ability to flex or deform before fracturing, a behavior similar to that exhibited by most metals under tensile or bending stresses. Because of this capability, HPFRCCs are more resistant to cracking and last considerably longer than normal concrete. Another extremely desirable property of HPFRCCs is their low density. A less dense, and hence lighter material means that HPFRCCs could eventually require much less energy to produce and handle, deeming them a more economic building material. Because of HPFRCCs’ lightweight composition and ability to strain harden, it has been proposed that they could eventually become a more durable and efficient alternative to typical concrete.
HPFRCCs are simply a subcategory of ductile fiber-reinforced cementititous composites (DFRCCs) that possess the ability to strain harden under both bending and tensile loads, not to be confused with other DFRCCs that only strain harden under bending loads
C) Manufacturening methods for producing contineous fiber composites
D) Function of skin and core in sandwich composite
A sandwich-structured composite is a special class of composite materials that is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density.
Laminates of glass or carbon fiber-reinforced thermoplastics or mainly thermoset polymers (unsaturated polyesters, epoxies...) are widely used as skin materials. Sheet metal is also used as skin material in some cases.
The core is bonded to the skins with an adhesive or with metal components by brazing together
The strength of the composite material is dependent largely on two factors:
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