FAA Airframe Prepware Sheet Metal Structures Practice Test

The radius of a bend when forming metal is commonly defined as the inside radius. This perspective is important because the inside radius of a bend reflects the actual amount of material distortion that occurs during the bending process. When metal is bent, the inner side of the bend experiences compression, while the outer side experiences tension. The inside radius is where the material is closest to the neutral axis—this is a crucial point for understanding stress distribution in the material. In most manufacturing and fabrication guidelines, unless otherwise specified, it is standard practice to reference the inside radius to ensure consistency in design and production. Understanding this concept aids in the accurate calculation of bend allowances and the successful creation of desired shapes in metalworking.