Composite Materials

 

One of the most demanding industries in the world is the aerospace industry. Every day scientists and engineers are trying to find new materials that can be used to bring the products of  this industry into a higher level and standard. In the early aviation years airplanes were made of lightweight wood and some kind of fabric. Then people started to use metal, something that improved at a great degree the stracture of the airplanes. In some cases they even used a combination of metal and wood. Nowadays we still use metal as the main material for airplane frames, wings and pretty much everything but in the last few years the airplane industry begun to use a new kind of materials that we call composites.

Text Box: Wright Flyer: Wooden and Fabric construction.

 

 

 

Early Airliner: Metal construction.

 
 

 

 


The word “composites” refers mainly to three materials: fiberglass, carbon fibers and kevlar. All these materials are fibers that require a resin solution to become an actual solid product. Some of the most known resins are: epoxy, polyester, vinyl ester, polypropylane, PEEK, etc. The fiber – resin ratio is essential for the strength of the product, therefore choosing the proper method of making composite materials you can obtain a 40% resin and a 60% fiber(vacuum infusion) which results to a very solid material.

 

 

 

 

 

 


 

Fiber glass

 

Carbon Fiber

 

Kevlar

 
 

 


 

 

 

There are lots of moulding methods from where a different result can be obtained. Such methods are:

·       Vacuum bag moulding

(click to watch video)

 

 

 

 

 

 

 

 

 

 

·       Autoclave moulding

 

 

 

 

·       Resin Transfer Moulding (RTM)

(click to watch video)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For all these methods a female and a male mould is used. One of the them is rigid (most of the time the lower mould) and the other one is usually flexible, made of composites or silicone or sometimes made of nylon films.

 

The main reasons that made composite materials so popular and widely used in such a demanding industry are there physical properties. In the nature these materials are not isotropic in general but they are orthotropic meaning, for example, that applying the same force from a different angle the stiffness will not be the same. Another major reason is that composite materials are very lightweight, strong and solid at the same time thanks to there mechanical and physical abilities.

 

Obviously composite materials came into our lives aiming to change everything we knew about constructing materials. Having a light, strong and solid enough material that can easily substitude metal means a lot, specifically when other problems such environmental ones have to be taken in consideration and when the need for the ultimate, efficiently talking, machine is raising.

 

 

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