Monocoque Construction

Monocoque body construction integrates the body and chassis of a vehicle together into a one piece structure. The body and drivetrain are integrated into a single unit by wielding the components together. The drivetrain and body are cast as one structure onto a frame. A monocoque body absorbs all or most of the stresses which the body is subjected to. 

Before the monocoque body construction became popular body-on-frame chassis was used for vehicle construction. A separate car body was mounted to a frame that supported the drivetrain. Body-on-frame was popular even after monocoque construction came into being because it was easy and relatively inexpensive to add a different type of body to create a different car that had the same chassis and drivetrain. The body-on-frame type of automobile construction had its limitations as the cars were very heavy which meant high fuel consumption and lower performance figures. Handling and road grip were compromised as the body tended to roll a lot while cornering as it never felt one with the drivetrain. Body-on-frame construction had a higher number of accident fatalities as crumple zones could not be integrated onto the car. 

Because a monocoque body construction integrates the frame of the vehicle to the drivetrain of the vehicle the car has better handling traits and lowers the kerb weight of the vehicle. A monocoque body construction improves the fuel economy of a vehicle and makes it safer for occupants in the event of a crash as crumple zones can be integrated into the body of the car. Modern monocoques are designed to distribute the load evenly over the body of the car such as the pillars of cars. High tensile steel panels are used in load bearing parts to make the structure of the car safe. The monocoque body construction technique is still under research and development for enhanced safety and better drive dynamics. Some monocoques have a bonded rear window glass which contributes to the structural integrity of the car.