dshaped

Dshaped is an adjective used to describe objects whose boundary or cross-section resembles the uppercase letter D. In two dimensions, a D-shaped figure consists of a straight line segment meeting a semicircular arc, forming a convex shape with a flat side and a curved side. If the straight edge has length h, the corresponding semicircular arc has radius r = h/2, and the overall width equals h. The area of this shape is (π h^2)/8 and the perimeter is h + (π h)/2. In three dimensions, a D-shaped solid is created by extruding this cross-section to form a D-shaped prism or similar full three-dimensional form.

D-shaped profiles are encountered in engineering and design where a flat edge is needed for mounting, orientation, or clearance, while retaining a rounded exterior. They are used for shafts, hubs, or fittings that require a non-circular cross-section to improve torque transmission or alignment, as well as in custom hardware, gaskets, and decorative components where a distinctive profile is desired.

Manufacturing methods include extrusion, milling, turning, or stamping to produce the D-shaped cross-section from metal or plastic. Additive manufacturing can realize variations with complex wall thicknesses, and processes such as injection molding or casting may be employed for mass production of D-shaped components. Tolerances and surface finish depend on the chosen fabrication method.

The term derives from the resemblance to the letter D, with the straight edge and the curved boundary defining the recognizable profile.