Question

Please Answer this in full detailed as I am unable to get the full grasp of this topic

a) (1) Sketch the off-axis strength of a unidirectional composite according to the maximum strength theory and (2) indicate the different failure modes. (3) Which parameters are needed to describe this off-axis strength and how can they be determined? [5 marks] b)(1) Sketch the compressive failure mode for a unidirectional carbon/epoxy composite and explain why the compressive strength of such a composites is lower that its tensile strength. (2) Which fibre reinforced epoxy composite has a compressive strength that is higher than its tensile strength? [5 marks] c) (1) Briefly describe a manufacturing process for continuous fibre reinforced metal matrix composites (MMC). (2) What are the main property advantages of MMC's over pure metals? Use diagrams whenever necessary [5 marks] d) (1) What is the main property advantage of CMC's over pure ceramics? (2) Explain this property advantage and the role of the fibre-matrix interface [5 marks e) 1) Explain the importance of wetting in adhesive bonding or fibre reinforced plastics. (2) How can it be measured and how can it be improved? [5 marks]

Answer 1

d) (1)When the ceramic materials are subjected to mechanical or thermal loads, Catastrophic failure occurs because ceramics do not show plastic deformation as metals It is plastically deformed due to its high dislocation mobility. Even a minor crack can spread so quickly or can grow to critical sizes that result in a sudden failure. Such kind of failure in Ceramic materials are produced due to a deadly characteristic, namely the lack of tenacity. Therefore, one of the main purposes of producing ceramic matrix composite materials is to improve the hardness. The main purpose of using reinforcement (such as fibers, particles and whiskers) in The polymer matrix compounds (PMC) and the metal matrix compounds (MMC) are to increase the Resistance of the composites, while the reinforcement used in the ceramic matrix composites. (CMCs) increases the tenacity of composites.

(2)By definition, ceramic matrix composite materials are materials in which one or more different ceramic materials the phases are added intentionally to another, to improve some properties that are not possessed For the monolithic ceramic materials. In ceramic matrix composite materials, a given ceramic matrix is Reinforced with discontinuous reinforcement, such as particles, whiskers or staple fibers or with continuous fibers. The basic reinforcements that are included in the ceramic matrices. They are carbon, glass, glass-ceramics, oxides and not oxides. The main function of the matrix is maintain the reinforcement phase in the desired orientation or location and act as a means of load transfer as well as protect the reinforcement of the environment. Whereas, the main objective of the Reinforcement is providing resistance to an otherwise brittle matrix.