chassis

Chassis is a term used to describe the main structural framework or enclosing body of a device, machine, or vehicle. It serves as the foundational support to which other components are mounted and aligned, and it often defines the layout and geometry of a system.

In automotive use, the chassis may refer to the underlying frame or the complete vehicle platform. There are two common concepts: body-on-frame, where a separate body sits on a rigid frame, and unibody (monocoque), where the body and frame are integrated. The chassis includes the frame or platform, suspension mounting points, steering geometry, and drivetrain attachment points. The choice between configurations affects rigidity, weight, crash performance, repairability, and ride characteristics.

In electronics and machinery, the chassis is the metal enclosure that houses circuits and components. It provides physical protection, electrical grounding, and shielding from electromagnetic interference. The chassis can form the reference ground in electrical systems and influences safety and EMI performance. In consumer electronics, it is often called the enclosure or shell.

In computing and data centers, the term refers to the system unit or server enclosure that contains the motherboard, power supply, drives, and expansion cards. Chassis form factors, such as ATX or rack-mounted designs, dictate dimensions, cooling layouts, and expansion capabilities.

Materials commonly used for chassis include steel and aluminum alloys, with composites used in some high-performance applications. Manufacturing methods include welding, stamping, casting, and extrusion.