Minimum Plate Bend Radius
Minimum inside bend radius and radius-to-thickness multiple to avoid cracking the outer fiber.
Example
You enter
- Plate / sheet thickness (in) 0.25
- Elongation in 2 in (%) 20
You get
- Radius-to-thickness (R/T) 1.5
- Minimum inside radius 0.375 in
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method.
Details, formula, and sources
ScopeFrom the published forming-limit relation R_min = T x (50 / %elongation - 1) and the mill-cert elongation. A screen; the mill cert, grain direction, and a test bend govern.
Formula or tableRadius-to-thickness multiple R/T = 50 / %elongation - 1; minimum inside radius R_min = thickness x R/T.
Source and editionMinimum inside bend radius from ductility - the published forming-limit relation R_min = T x (50 / %elongation - 1), by name; public domain.
Free accessThe published forming-limit relation; the thickness and mill-cert elongation are user-supplied.
What governsEstimate. AHJ and licensed professional govern.
API field namesthickness_in, elongation_pct, r_over_t, r_min_in
- Elongation total percent in 2 in from the mill cert (A36 about 20); domain (0, 50]mill certificate
- Grain direction transverse bends tolerate tighter radii than longitudinal; screen onlyforming practice