Lamborghini’s Forged Carbon Fiber

Lamborghini’s Forged Composite The New Carbon Fiber 2 Carbon Fiber & It’s Beginning Carbon Fiber is arguably one of the strongest, most advanced, and most influential materials made by human civilization since the bronze and iron ages over 5,000 years ago. Carbon fiber is primarily known and utilized for its extremely high strength-to-weight ratio. Carbon fiber was originally unveiled to the market in applications of high-stress and low weight requirements. It is most notably used in the aircraft industry, high-end automotive industry, and in many different sporting industries like tennis, golf, and cycling. For the sake of concision, I will be focusing mainly on the automotive industry throughout my research. The creation of graphite “whiskers” was the main advancement which lead to discovery of the highly successful material. Roger Bacon, in 1958, discovered these “perfect carbon whiskers” while he was examining carbon deposits from his company’s carbon arc lightbulbs which they were producing at the time. Bacon explains; “I would examine these deposits, and when I broke one open to look at the structure, I found all these whiskers,” he says. “They were imbedded like straws in brick. They were up to an inch long, and they had amazing properties. They were only a tenth of the diameter of a human hair, but you could bend them and kink them and they weren’t brittle. They were long filaments of perfect graphite.” These fibers were researched, processed, and re-manufactured into long strands, then lattice-woven into a fabric which called a carbon sheet (shown on the right). This process is where carbon fiber gets it’s iconic squarewoven look. 3 While traditional carbon fiber is very revolutionary in both its strength and its light weight, it has several drawbacks when it comes to creating usable parts from the material. To create a part from carbon fiber, you must first create and use a mold for the desired geometry of the part. This can prove challenging in itself if you are trying to create a geometrically complex shape. Next you must lay the sheets of carbon fiber inside, or on top of the mold, depending on molds design. Once the carbon is laid, several sheets of plastics, foam, and other fabrics are placed surrounding the part as to prevent air bubbles or wrinkles in the epoxy or the carbon. Finally, once the part is fully prepped, it can now go into a pressurized over where the resin epoxy can be injected between the part and its surrounding plastic dressing. In the manufacturing process, the designer or creator has some freedom in the number of layers of carbon fiber sheets to put on the part or in certain areas. More carbon gives more strength but it also adds more weight, cost, and preparation time for the given part. “It’s really a labor intensive process, and the persons involved in manufacturing really need to know they’re doing to get the desired result” explains the mastermind behind the 100% carbon fiber chassis sports car, Christian von Koenigsegg. (THE DRIVE) Lamborghini & Callaway’s Innovation Researchers at the Seattle based Automobili Lamborghini Advanced Composite Structures Lab (ACSL) developed a new way of creating carbon fiber parts. The new carbonbased material is called Forged Composite. It is able to utilize the strength and weight advantages found in traditional woven carbon fiber, while introducing the ease of laying fiberglass. This process can trim off hours from the expected preparation time of a given part. The main advancement lies within the fundamental way in which individual carbon fibers are 4 aligned within the sheet. Traditionally, long strands of graphite are drawn and woven into a lattice like fabric. Developers at Lamborghini’s collaboration with Callaway golf company has found that “crushing” the carbon strands into tiny turbostratic, or randomly aligned, fibers can then be mixed with epoxy before forming. This creates a sort of paste which can be sprayed or injected into a mold, and simply pressurized, without having to apply increased temperatures with an autoclave. Lamborghini estimates that any part can anticipate a 44% minimum decrease in manufacturing time (Feraboli, Paolo). The Forged Composite contains roughly 500,000, or half a million turbostratic fibers per square inch of material. This random alignment of fibers helps maintain load distribution as well as abolishing the need for excessive attentiveness to alignment of fibers when creating a part. Source: https://www.quantumcomposites.com/pdf/papers/2011-ASC-montreal-forged-suspens.pdf The table above shows tensile strength and modulus of 6-series aluminum, two traditional woven carbon fibers, and the Forged Composite. Notice that the tensile strength of the Forged Composite is lower than traditional carbon fiber as its more comparable to aluminum, yet their tension modulus is very similar. This shows that the new, easier to produce, Forged Composite suffers slight loss in strength due to its turbostratic fibers when compared to woven carbon fiber, while simultaneously maintaining nearly the same stiffness properties. Unlike woven Carbon sheets, Forged Composite is completely isotropic, meaning that is can sustain a load in any direction in the same manner. The main feats of this material are that it drastically decreases 5 preparation time, and therefore labor, thus increasing production capacity, lowering costs and number of components, and allowing for a more automated process throughout. Considering the Forged Composite is more similar to fiber-glass than to carbon fiber, it can more easily be applied to more complex parts with complex shapes, which prove difficult when dealing with woven carbon sheets. This technology also provides much more design freedom as molds can get more sophisticated in shape, while reducing the complexity of the mold itself by using less parts. Forged Composite molds can more easily be machined to the right specifications. While there is a slight loss is overall strength of the Forged Composite, it can be more synonymous with aluminum. Any application which calls for aluminum can be substituted with the Forged Composite at roughly the same strength while maintaining about a 50% weight reduction at the same time. On the other hand, woven carbon fiber is comparable to steel in its overall strength, and at a fifth of the weight. What’s Next? Lamborghini originally unveiled its recent discovery in 2010 in the form of the Sesto Elemento, which stands for sixth element, denoting the atomic number of carbon. This was Lamborghini’s first public display of the Forged Composite technology. The highly limited, track-only model was made up of the forged carbon fiber composite in its chassis, body, driveshaft, and several suspension components, as well as many trim parts to assist the “sixth element” into its 2,200 lb. curb weight. As for Callaway golf company, Forged Composite was the primary material of choice in their Diablo Octane driver (pictured below). This provides an impressive average range increase of 8 yards due to its increased power-to-weight ratio. Callaway claims it “will overpower 6 titanium” in the golf industry as it is even lighter and stronger, and provides a greater head speed (Callaway Diablo Octane). The world of composites is everchanging and continually advancing to find more and more successful materials for their specific desired properties. More unique materials are on the rise day by day and more breakthroughs are destined to surface in more industries than just automotive and sports.