The value that describes this repositioning of the neutral plane is called the 'k-factor.' īend Allowance (BA) is calculated using the general equation:ī.A. Typically, the plane repositions at a distance of one-third to one-half the thickness of the material. However, when the bending forces exceed the elastic limit, the neutral plane moves towards the inner surface of the bend. If a sheet material is uniform in section and its elastic limit is not exceeded, then its neutral plane (or axis in 2D) coincides with the centerline of the material. Bend allowance is calculated based on bend angle, material thickness, and inside radius.
