Hohlkörpers

Hohlkörpers, or hollow bodies, are three-dimensional objects that enclose hollow space inside a solid exterior. They consist of an outer surface and one or more inner surfaces that bound empty space.

In geometry, a hollow body is the material region between an outer boundary and one or more inner boundaries. Common examples include hollow spheres, hollow cylinders, and shell-like forms. The term contrasts with solid bodies, which have no internal cavities.

Key measures are the volume of material and the surface area of all boundaries. The material volume equals the outer volume minus the volumes of any cavities. The wall thickness is the distance between inner and outer surfaces and affects strength, stiffness, and weight.

Applications include weight-reduced components in aerospace and automotive engineering, oil and gas equipment, and consumer products. Hollow shapes are also used in heat exchangers, acoustics, packaging, architecture, and sculpture.

Manufacturing methods to create hollow bodies include casting with cores to form cavities, subtractive machining to bore internal cavities, and additive manufacturing for complex hollow geometries. In mathematics, hollow bodies are studied for their topology and geometry, including cases with multiple cavities or interconnected pores.