The concept of the cage-like car body can be traced back to 1944, developing from the analogy of a car body to a birdcage. With the advancement of new manufacturing materials, since the 1970s, high-strength steel, ultra-high-strength steel, and advanced composite materials have been widely used in the manufacture of cage-like car bodies, significantly improving their strength and impact resistance. The design divides the entire car body into two areas: an impact crumple zone to absorb impact force during a collision and a "high-strength cabin area" to ensure the survival of passengers, thus enhancing the necessary functions in each area. Based on the cage-like car body concept, the structure utilizes the impact crumple zones at the front and rear to absorb impact energy and reduce cabin deformation, while the high-strength cabin area focuses on improving structural rigidity and dispersing the energy transmitted from the impact crumple zones, allowing the car body to maintain the integrity of the cabin area during a collision. The GOA (Global Outstanding Assessment) safety body design is essentially based on the concept of an impact-absorbing body and a high-strength passenger compartment, similar to the ZBC design concept.
Most modern sedans use a cage-like body design; for example, the Focus employs a cage-like reinforced body structure and uses high-strength steel to enhance body rigidity. The front and rear impact buffers and door anti-collision beams all utilize the same reinforced structure. The impact buffers distribute the impact force evenly across the entire vehicle body, thus preventing passenger injuries.
