Smart Materials and Structures

Composites Manufacturing

ME 338: Manufacturing Processes II Instructor: Ramesh Singh; Notes: Prof. Singh/ Ganesh Soni

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Composites

ME 338: Manufacturing Processes II Instructor: Ramesh Singh; Notes: Prof. Singh/ Ganesh Soni

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What is a composite Material?
• Two or more chemically distinct materials combined to have improved properties
– Natural/synthetic – Wood is a natural composite of cellulose fiber and lignin.
• Cellulose provides strength and the lignin is the "glue" that bonds and stabilizes the fiber. • Bamboo is a wood with hollow cylindrical shape which results in a very light yet stiff structure. Composite fishing poles and golf club shafts copy this design.

– The ancient Egyptians manufactured composites!
• Adobe bricks are a good example which was a combination of mud and straw
ME 338: Manufacturing Processes II Instructor: Ramesh Singh; Notes: Prof. Singh/ Ganesh Soni

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COMPOSITES
A composite material consists of two phases: • Primary
– Forms the matrix within which the secondary phase is imbedded – Any of three basic material types: polymers, metals, or ceramics

• Secondary
– Referred to as the imbedded phase or called the reinforcing agent – Serves to strengthen the composite (fibers, particles, etc.) – Can be one of the three basic materials or an element such as carbon or boron

ME 338: Manufacturing Processes II Instructor: Ramesh Singh; Notes: Prof. Singh/ Ganesh Soni

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Types of composite materials
There are five basic types of composite materials: Fiber, particle, flake, laminar or layered and filled composites.

ME 338: Manufacturing Processes II Instructor: Ramesh Singh; Notes: Prof. Singh/ Ganesh Soni

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Classification of composite material
• Metal Matrix Composites (MMCs) – Mixtures of ceramics and metals, such as cemented carbides and other cermets – Aluminum or magnesium reinforced by strong, high stiffness fibers • Ceramic Matrix Composites (CMCs) – Least common composite matrix