ANS:D - thickness of sheet

Springback in sheet metal bending does indeed depend on various factors, and one of these important factors is the thickness of the sheet. Explanation:

1. Material Behavior: Thicker sheets generally exhibit less springback compared to thinner sheets. This is because thicker sheets have a higher resistance to bending forces due to their increased cross-sectional area. Thicker sheets require higher bending forces to deform them, which can lead to greater plastic deformation and less elastic recovery upon release of the bending force.
2. Bending Radius: While the bend radius also affects springback, thicker sheets typically require larger bend radii to minimize springback. This is because thicker sheets are less ductile and more prone to cracking if subjected to tight bending radii, leading to increased springback.
3. Degree of Bend: The degree of bend can influence springback, but it is often related to the thickness of the sheet. Thicker sheets may require larger bending angles to achieve the desired shape, which can affect the amount of springback experienced.
4. Material Properties: The material properties, including the elastic modulus and yield strength, also play a role in determining springback. Thicker sheets may have different material properties compared to thinner sheets, which can affect their behavior during bending and subsequent springback.

In summary, while the elastic limit is indeed critical in determining the extent of permanent deformation (plastic deformation) during bending, the thickness of the sheet is also a significant factor influencing springback in sheet metal bending processes. Thicker sheets generally exhibit less springback due to their increased resistance to bending forces and greater tendency for plastic deformation.