What is meant by the neutral axis in bending?

What is meant by the neutral axis in bending?

• A. The line inside the material where there is no temperature change during bending
• B. The line within the material where there is no tensile or compressive strain during bending
• C. The edge of the sheet metal after bending
• D. The bend line

Answer: (B)

When metal is bent, fibers on one side of the cross-section are squeezed (compression) and fibers on the other side are pulled (tension). There is a line through the thickness where the length doesn’t change at all during bending. That line is the neutral axis. It lies inside the material, parallel to the bend, and marks zero longitudinal strain for the bend. This is different from any temperature effect, the outer edge, or the bend line itself, which are not about zero strain. So the neutral axis is the location where there is no tensile or compressive strain during bending.

When metal is bent, fibers on one side of the cross-section are squeezed (compression) and fibers on the other side are pulled (tension). There is a line through the thickness where the length doesn’t change at all during bending. That line is the neutral axis. It lies inside the material, parallel to the bend, and marks zero longitudinal strain for the bend. This is different from any temperature effect, the outer edge, or the bend line itself, which are not about zero strain. So the neutral axis is the location where there is no tensile or compressive strain during bending.