The integrated frame and body type of construction (fig. 8-3) also referred to as unitized construction, combines the frame and body into a single, one-piece structure. This is done by welding the components together, by forming or casting the entire structure as one piece, or by a combination of these techniques. Simply by welding a body to a conventional frame, however, does not constitute an

Figure 8-3.- Integrated frame and body.

integral frame and body construction. In a truly integrated structure, the entire frame-body unit is treated as a load-carrying member that reacts to all loads experienced by the vehicle-road loads as well as cargo loads.

Integrated-type bodies for wheeled vehicles are fabricated by welding preformed metal panels together. The panels are preformed in various load-bearing shapes that are located and oriented so as to result in a uniformly stressed structure. Some portions of the integrated structure resemble framelike components, while other resembles bodylike panels. This is not surprising, because the structure must perform the functions of both of these elements.

An integrated frame and body type construction allows an increase in the amount of noise transmitted into the passenger compartment of the vehicle. However, this disadvantage is negated by the following advantages:

Substantial weight reduction, which is possible when using a well-designed unitized body

Lower cargo floor and vehicle height

Protection from mud and water required for drive line components on amphibious vehicles

Reduction in the amount of vibration present in the vehicle structure