WAQAR ALIMS MECHANICAL ENGINEERING

UNIVERSITY OF LAHORE SUBJECT:-ASSIGNMENT NO 01 OF MECHANICS OF COMPOSITE MATERIAL

COMPOSITE MATERIAL

A composite material (also called a composition material or shortened to composite) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials.

Typical engineered composite materials include:

Composite building materials, such as cements, concrete

Reinforced plastics , such as fiber-reinforced polymer Metal  composites Ceramic composites (composite ceramic and metal matrices)

Fiber-Reinforced Composites Fiber-Reinforced Composites often aim to improve the strength to weight and stiffness to weight ratios (i.e. desire light-weight structures that are strong and stiff!). Glass or Metal Fibers are generally embedded in polymeric matrices. Fibers are available in 3 basic forms: Continuous Fibers are long, straight and generally layed-up parallel to each other. Chopped Fibers are short and generally randomly distributed (fiberglass). Woven Fibers come in cloth form and provide multidirectional strength.

APPLICATION Composite materials are generally used for buildings, bridges, and structures such as boat hulls, swimming pool panels, race car bodies, shower stalls, bathtubs, storage tanks, imitation granite and cultured marble sinks and countertops. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments.

NON-CRIMP FABRIC COMPOSITE MATERIAL

Non-crimp fabric (NCF) composites are reinforced with mats of straight (non-crimped) fibers, giving them such advantages as strength, ease of handling and low manufacturing costs. “Non-crimp fabrics” (NCF), also refers to a long-standing challenge faced by designers of composite parts: to combine a perfect placement of the reinforcing fibers with easy, inexpensive, automated manufacturing of the part. A part made using unidirectional tapes, placed by hand or by robot and consolidated in an autoclave, has ideal fiber placement

and the best local mechanical properties due to the unidirectional (UD) microstructure of the reinforcement. However, the manufacture of such parts is cumbersome and costly. On the other hand, an out-of-autoclave manufacturing process, for example vacuum assisted RTM, which uses woven laminates, is relatively cheap and takes advantage of easy handling of large sheets of the fabric. In this case, however, the local mechanical properties are affected, because the fibers deviate from their ideal directions due to the crimp (inherent to the woven fabric) and because of the necessary presence of the second fiber system, lying transverse to the direction of the design loads. Hence the challenge to create a reinforcement which would combine unidirectional fibers with integrity, ease of handling and drape of textile fabrics.APPLICATIONS

Floor pan TECABS (Technologies for Carbon fiber reinforced modular Automotive Body Structures) projects

Rear pressure bulkhead, Belly Fairing, Vertical Tail (AIRBUS)