Composite materials in automotive engineering
The use of composite materials for the manufacturing of racing cars was a significant milestone of achievement in the automotive industry, as the earliest racing cars were made mostly with a single aluminum chassis, which was prone to major fractures. In the late 1980s, the use of advanced composite material in the racing industry caused a revolution of sorts in the world of automobile engineering. Such composites provided an apt solution for racing car chassis, as these were not only lightweight, but also sturdy and robust, offering the driver much more security, if the car were to crash.
Slowly and steadily, of such materials were being used in production sports cars as well because they increasingly became cost effective, and today; in the 21st century, the use of composite materials in a car/automotive manufacturing is more or less the norm.
The earliest composite materials included fiberglass, developed in the 1940s; however, this material did not make its way through to the automotive industry at that point of time, due to limitations in the then automotive engineering techniques. Today, fiberglass is used extensively for just about everything, including surfboards, building panels, boat hulls, and of course a car chassis.
The advantage of composite materials over normal single layered metals is the fact that these are many times stronger and lighter than the latter. As a result, the use of such a composite material not only decreases the overall weight of the object, but is also, compared to single layered materials, much more break resistant.
Composite materials are developed by the combination of two or more materials, with quite different properties. The individual materials, when coalesced together, for a unique material that has properties of its very own, although they do not blend in such a way as to loose their individual properties. This is what makes a composite material tougher than the original materials that are used in the composition.
When a composite material is made (usually of two materials), one material is called the matrix or binder, which surrounds and holds a cluster of fragments of a much stronger material, called the reinforcement, which is the second material.
The reinforcing and the matrix elements undergo a molding method, in which these materials are combined and compacted. There are various types of molding methods, including autoclave molding, vacuum bag molding, and resin transfer molding, among others. In automobile engineering, tooling materials used for the manufacture of composites include invar, aluminum, carbon fiber, steel and reinforced silicon rubber.
Automobile manufacturers use compression molding methods for the production of chassis, in which the composite materials are transformed into either a sheet molding compound (SMC) or a bulk molding compound (BMC). The former is like a plastic sheet reinforced with fibers that are continuous, and the latter is a plastic lump combined with short fibers. The recent innovations in the sphere of advanced composites in the automotive manufacturing industry have led to the use of carbon fiber reinforced plastic (CFRP), with various thermoset composites, including aramid fiber and carbon fiber in a matrix of epoxy resin.
The Formula 1 race cars in the early 90s had chasses are built with plastics reinforced with carbon fibers. In this process, a resin sheet is laid, already containing the carbon fiber reinforcement. This is kept in a mold, which is then placed in a pressure tight high grade oven, or autoclave, with very high temperature and pressure. This baking process ultimately produces the hard set resin composite.
Composite materials are used for high performance race cars, as well as for aerospace components, as the materials that build these should be lightweight as well as strong enough to withstand harsh conditions, including high temperature and incredible stress and strain.
Carbon composites are the primary material used in launch vehicles, spacecrafts and inter-stage structural components, in the aeronautics industry.
(Image. Minardi F1 “Coca cola” car sidepods made with Windform XT composite material. The image is property of Windform.it)