IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
Composites materials
(Nov. 2019)
A. M. Metawea

INTRODUCTION
MATERIALS
HAVE
AN
OBVIOUS
INFLUENCE
ON
HUMANKIND, THAT PERIODS OF HISTORY HAVE BEEN
NAMED AFTER MATERIALS. COMPOSITES MATERIALS ARE
ONE OF THE DOMINANT MATERIALS THAT HAVE GROWN
STEADILY OVER THE LAST FIFTY YEARS.
COMPOSITES
MATERIALS HAVE PENETRATED NEW MARKETS WITH SO
MANY APPLICATIONS. COMPOSITES MATERIAL IS A
MATERIAL MADE FROM MORE THAN ONE MATERIAL TO
CHANGE THE PHYSICAL AND CHEMICAL PROPERTIES OF
THE MAIN COMPONENTS. GETTING A NEW MATERIAL WITH
MORE PREFERRED CHARACTERISTICS IS THE MAIN GOAL
OF COMPOSITES MATERIALS. VARIOUS METHODS OF
ADDING MATERIALS TOGETHER TO GET EXACT NEW
COMPOSITES MATERIAL WITH EXACT CHARACTERISTICS,
EACH HAS ITS ADVANTAGES AND DISADVANTAGES THAT
SHOULD BE CHOSEN CAREFULLY TO PERFORM IT RIGHT.
METHOD
Choosing an exact manufacturing process mainly
depends on the type of matrix and fibers, the costeffectiveness and the required temperature to form
the part. Fiber Composite Matrix is mainly made of
adding Fiber to provide strength and stiffness to
Matrix to protect and transfer load through fibers. The
manufacturing process is very important that it should
be considered initially. Each manufacturing process
has its advantages and disadvantages and its exact
limitations on the structural design of the part.
Therefore, limitations, cost, production rate,
advantages, and disadvantages should be
considered by the designer. There are three main
types of composites manufacturing processes; open
molding closed molding and cast polymer molding.
Some methods will be illustrated properly including
their pros and cons and technique. Open means that
the raw material is exposed to air while their cure or
hardening.
Three methods are included.
1) Hand Lay-up
Pros:
•
Common and cheapest.
•
Suitable for manufacturing a variety of
composite products from all sizes (small to large).
•
Simple processing and low-cost tools.
Cons:
•
Production quantity per mold is low, but this
can be handled using many molds.
•
Need many skillful operators who can bear
hard physical work.
The technique:
First, the gel coat is applied to the mold to
preserve a high-quality surface.
Roll stock fiberglass reinforcement is manually
placed on the mold after the gel is cured.
The laminating resin is then added by either
pouring, brushing or using a paint roller (it is used to
consolidate the laminate, remove the air and
completely wet the reinforcement).
Other layers of fiberglass reinforcement are
added to build laminate thickness.
Low-density core materials as end-grain balsa,
foam, and honeycomb can be used to stiffen the
laminate.
2) Spray-up
Pros:
Suitable for manufacturing a variety of composite
products from all sizes (small to large).
Faster than Hand Lay-up method in molding complex
shapes.
Simple processing and low-cost tools.
Portable equipment allows for on-site fabrication with
almost no size limitations.
The operator can control thickness and consistency.
Cons:
Production quantity per mold is low, but this can be
handled using many molds.
It depends more on the operator.
Technique:
First, the gel coat is applied to the mold to preserve a
high-quality surface.
Strand glass and resin are then added using a
chopper gun on the mold.
The laminate is rolled to make all glass strands
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
saturated and compact the chop.
More layers are added to get the needed thickness.
Roll stock reinforcements, such as woven roving or
knitted fabrics, can be used in conjunction with the
chopped laminates.
The third process is open molding is Filament
Winding that also has its advantages, disadvantages,
production rate and technique. A quick look at the
other two types of molding; closed molding and cast
polymer molding will be provided. In closed molding,
raw materials cure inside a vacuum bag or a twosided mold. It is usually automated and requires
special large equipment with a high production rate.
Vacuum Bag Molding, Vacuum Infusion Processing,
Resin Transfer Molding, Compression Molding,
Pultrusion, Centrifugal Casting, and continuous
lamination are all types of closed molding with their
special pros and cons and techniques. The main
disadvantage of the closed Molding is that it requires
high-cost equipment and professional labors, while
the advantages of these processes are a high rate of
production and high efficiency. Cast polymers are
unique; they don’t have fiber reinforcements. They
are designed to make a specific shape and size with
specific strength for an exact application. Gel Coated
Cultured Stone Molding and Solid Surface Molding
are types of Cast Polymer Molding.
Results
3) Many applications are developed from the
composites materials, which as shown has provided
us with new preferred characteristics. With all these
benefits, another aspect designers should consider
carefully, which is a failure. Failure of a structural
element happens when this element cannot perform
its intended function. It seems obvious that material
failure is the only type of failure, yet, it is not.
Excessive deflection is also a type of failure that
occurs when the performance of the structure is
compromised. The element does not need to be
collapsed to be considered failed, partially damaged
materials could also be considered damaged.
Fracture and damage are harder to predict than
deflections. To design well, a designer should
consider testing the strength of the design and
developing tools to select materials with dimensions
and configurations to help the structure perform its
function safely.
Discussion
1) A brief look at manufacturing processes has been
provided with insightful describing of two important
processes. The strength which is a significant factor
of composites material was illustrated briefly. Many
applications were developed to gain more efficiency
when manufactured from composites materials. Wind
turbines blades for example made from composites
material to increase its strength and ability to bear
high wind velocities and forces on the blades and also
became lighter and perform better with higher
efficiency. A good designer carefully considers the
material is chosen, manufacturing process, strength,
cost, and efficiency. Testing the design before
construction can be done using finite element
analysis. Materials may be tested during and after
construction through ultrasonic, thermography,
Shearography, and X-ray radiography.
References
E. J. Barbero, Introduction to composite materials
design. Boca Raton, FL: CRC Press, Taylor & Francis,
2018.
“Desktop Engineering Magazine - The Life of Composite
Materials,” archive.is, 02-Dec-2007. [Online]. Available:
https://archive.is/20071202141018/http://66.195.41.10/Ar
ticles/Feature/The-Life-of-Composite-Materials200704101800.html. [Accessed: 01-Nov-2019].
“All You Need to Know About Composites,” Composites
Lab. [Online]. Available: http://compositeslab.com/.
[Accessed: 01-Nov-2019].
M. Hinton and A. Kaddour, “The background to Part B of
the Second World-Wide Failure Exercise: Evaluation of
theories for predicting failure in polymer composite
laminates under three-dimensional states of stress,”
Journal of Composite Materials, vol. 47, no. 6-7, pp.
643–652, 2013.