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Saturday, December 25, 2010

CFRP Component for BMW

Last June, BMW has announced a trio of new aero components for the M3 family, including a small rear lip spoiler, mirror caps and a new front splitter.


These components are made from carbon fibre reinforced plastic - the same super-light and super-tough material used in the M3's roof panel - the new BMW Performance parts are also coated in an ultraviolet-resistant laminate, protecting against yellowing, cracking and degradation.



Sunday, December 19, 2010

Composite Fabrication : Resin Transfer Molding (RTM)

RTM or Resin Transfer Molding is a closed mold process. In this process, matched male and female molds are being used. Before the process injection, fiber pre-form is places in the mold cavity. Then the molds are clamped. Resin mix then is injected or transferred into the cavity through injection ports at a relatively low pressure.
Schematic diagram of RTM process
Injection pressure is normally less than 690 kPa (or 100psi). The displaced air is allowed to escape through vents to avoid dry spots. Cure cycle is dependent on part thickness, type of resin system and the temperature of the mold and resin system. The part cures in the mold, normally heated by controller, and is ready for its removal from the mold when sufficient green strength is attained.

RTM offers the promise of producing low cost FRP parts with complex structures and large near net shapes. Relatively fast cycle times with good surface definition and appearance are easily achievable. The ability to consolidate parts allows the saving of considerable amount of time over conventional lay-up processes.
Example of RTM Machine
Since RTM is not limited by the size of the autoclave or by pressure, new tooling approaches can be utilized to fabricate large, complicated structures. However, the development of the RTM process has not fulfilled its full potential. For example, the RTM process is yet to be automated in operations such as preforming, reinforcement loading, demolding, and trimming. Therefore, RTM can be considered an intermediate volume molding process.

Several unresolved issues in RTM encountered by composite engineers are in the areas of process automation, preforming, tooling, mold flow analysis and resin chemistry. During the last decade, rapid advances in RTM technology development have demonstrated the potential of the RTM process for producing advanced fibre reinforced plastic and composite parts.
RTM Simulation

Product of RTM Process

Tuesday, December 14, 2010

Oscar With His CFRP Composite Legs

Carbon Fibre Reinforced Plastic (CFRP) composite legs is a product that composite researchers and designers can be proud of. Made from carbon fibre and being design for disabled person.

And who doesnt know Oscar Pistorius, gold medalist in paralympic, a double amputee, who uses carbon fibre composite legs. He is also known as the "Blade Runner" and "the fastest man on no legs". 

He is better than a normal person, thanks to fibre reinforced and composite technology. He’s already considered one of the fastest men in the world.

Oscar Pistorius with CFRP Legs

Also read :
Carbon Fiber Composite Running Legs - Composite Material Blog

Sunday, December 12, 2010

Sandwich Composite and Core Material

Sandwich composite, considered to be a class of structural composites consist of two strong outer sheets or faces separated by a layer of less dense material or core, which has lower stiffness and lower strength. The faces bear most of the in-plane loading and also any transverse bending strength. Typical face material include aluminum alloys fiber reinforced plastics titanium steel and plywood.

Structurally the core serves two functions. First it separates the faces resist deformations perpendicular to the face plane. Secondly it provides a certain degree of shear rigidity along planes which are perpendicular to the faces. Various materials and structures are utilized for cores including foamed polymers synthetic rubber inorganic cements as well as balsa wood.

Another popular core consist of a honeycomb structure-thin foil that have been formed into interlocking hexagonal cells with axes oriented perpendicular to the face planes. The material of which the honeycomb is made may be similar to the face material. Sandwich panels are found widely in a wide variety of applications they include roofs floors and wall of building and in aircraft for wing fuselage and tail plane skins.

Structural sandwich construction is one of the first forms of composite structures to have attained broad acceptance and usage. Virtually all commercial airliners and helicopters and nearly all military air and space vehicles make extensive usage of sandwich construction. In recent years, most commercial space vehicles have also adopted this technology for many components

Example of Sandwich Composite, Using Honeycomb Core

Thursday, December 9, 2010

Kaizen : From Composite Technology to Fibre Reinforced Plastic

Lately we have made some improvement to our weblog. We changed our name from CompositeTechnology.blogspot to Fibre-Reinforced-Plastic.com. This is we think a best name for this weblog as this resource centre only talk about plastic/polymer composite, while composite represent a wide range of material including metal matrix composite and ceramic matrix composite.
Besides that, we redesign this page to look more attractive and more visitors friendly.

Next step, we will create a Fibre Reinforced Plastic community on facebook, to discuss and share our knowledge concerning polymer composite and fibre reinforced plastic (FRP) issues. We hope to hear comments from all students, researchers and FRP engineers out there!

- Mr Joe Jeff

Monday, December 6, 2010

Laminate Structure and Classification in FRP

The last post we discuss about lamina and laminate terminology and definition. This post will talk about laminate classification. Laminates can be classified according to the fiber orientation :

• Unidirectional Laminate- The fiber angle in any ply is parallel to the fiber angle in every other ply. This is a thick lamina from a mechanics point of view.

• Cross Ply Laminate - The fiber angle in any ply is normal to at least one other ply and parallel to any other ply or plies (i.e., contains only 0 and 90E plies).

• Angle Ply Laminate - Fiber angle of any ply is not restricted to parallel and normal directions. These definitions have different consequences depending upon whether the fiber directions are defined by their fabrication direction or loading direction. For the purposes of composite design the fiber directions relative to the loading directions are relevant. For, instance if laminate is fabricated by laying up 0 and 90E plies, it can be used as cross ply or an angle ply laminate. Laminates can also be classified based on stacking sequence.

• Symmetric Laminate – In a symmetric laminate all plies above the midplane have the same angle as the ply in the equivalent position below the midplane (i.e., the midplane of the laminate is a plane of symmetry).

• Antisymmetric Laminate - All plies above the midplane have the opposite (negative) angle as the ply in the equivalent position below the midplane. (The midplane is a plane of antisymmetry)

• Asymmetric Laminate - The midplane is not a plane of symmetry or antisymmetry.

Friday, December 3, 2010

Lamina and Laminate, What Is That?

So, what is lamina? What is laminate? What is the different?
Let us talk about lamina first.

A lamina is a flat (or sometimes curved) arrangement of unidirectional (or woven) fibers suspended in a matrix material. A lamina is generally assumed to be orthotropic, and its thickness depends on the material from which it is made.

For example, a graphite/epoxy (graphite fibers suspended in an epoxy matrix) lamina may be on the order of 0.127 mm thick. For the purpose of analysis, a lamina is typically modeled as having one layer of fibers through the thickness. This is only a model and not a true representation of fiber arrangement. Both unidirectional and woven laminas are schematically shown below.


Schematic illustration of lamina composite

While a laminate is a stack of lamina, as illustrated below, oriented in a specific manner to achieve a desired result. Individual lamina is bonded together by a curing procedure that depends on the material system used. The mechanical response of a laminate is different from that of the individual lamina that forms it. The laminate’s response depends on the properties of each lamina, as well as the order in which the lamina are stacked.


Schematic of laminate composite

So, to construct a product (laminate) we have to use a several lamina with determined orientation to achieve properties that we want. Usually, lamina is not used without stacking it to create a laminate. These lamina is being hold together thanks to the resin that we choose depending on service conditon of the product.