What is Monocoque Construction?
The term monocoque means the chassis integrates with the complete body as one part. It is a French term that means 'single shell' or 'single hull.' Monocoque construction is significant for reducing the vehicle's overall weight by integrating the chassis and the body into a single unit. Other vehicle components such as power train, steering, suspension, and brakes are directly mounted to the vehicle's body in this design. In monocoque construction, the exterior skin supports the structural load. Hence, it is also called structural skin.
Manufacturers directly attach these components to the body or onto the sub-frames, which are then mounted to the main body. Many modern vehicles use monocoque construction. Manufacturers especially plan and design monocoque structures with the help of crumple zones to keep away the shock of occupants' impact. Thus, it improves the safety of the driver and the passengers of the vehicle. Earlier, a monocoque chassis was first used in a car during the year 1942. Nowadays, the manufacturers focus on making the monocoque chassis stronger, affordable, and lighter than before.
Traditionally, there are two methods for manufacturing a car body.
- A separate chassis frame and body shell bolted together.
2. chassis and body combined into a shell or assembly. This is the most common method of manufacturing a car's body in most countries in the world. The main advantage of this structure over separate chassis design is higher strength and lighter weight. This is because parts of the body panels add to the strength with a lighter structure.
Monocoque frame, which is essentially one large body panel, relies on body panels for their structural integrity. Manufacturers use these frames in sports cars and, also in some race cars. Some manufacturers use carbon fiber material to make monocoque chassis, as it considerably reduces the vehicle's weight. Besides, it offers increased impact strength as compared to the metal monocoque chassis. As the car’s weight decreases, its performance, such as power and speed, also improves. The vehicle also consumes less fuel. The car's overall performance improves as the rest of the parts are fitted to the vehicle body, directly eliminating the chassis' need.
Furthermore, you can use monocoque chassis technology only for regular vehicles such as cars. However, it is not suitable for commercial vehicles where they need a bigger chassis. One of the examples of monocoque technology is a Formula one car. These cars may look unsafe or unstable from the outside because they use fiberglass to make the monocoque chassis. However, monocoque chassis offers great safety to the driver from any impact. Besides, Formula one cars are very lightweight as their makers use fiberglass material.
Unibody or Unitised Conctruction
Unitised Constructions is a structure in which the car’s body, chassis, and floor pan form a single unit. This makes the car weigh less. Most modern cars have unitized constructions, i.e., a car in which the body, chassis, and floor pan forms a single structure. Another name for this type of construction is a unitary construction.
Manufacturers popularly call it as the 'ladder on a frame' design. It means the frame of the car is made out of one large piece. Another name for it is unibody construction. This design makes the vehicle lighter and provides good structural rigidity.
Manufacturers use uni-body construction design to make most of the trucks, crossovers, and SUVs. It is also quite useful for off-roading vehicles as it provides flexibility when driving over the boulders. Manufacturers across the world use this design in their vehicles. The advantages of unitized construction cars are they are low in weight and less noisy. However, the main disadvantage of this design is the lower towing capacity of the car.
Title image - Courtesy Hyundai
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