• Kesti, Vili
• Pokka, Aki-Petteri
• Kaijalainen, Antti

Abstract

<jats:p>Abstract. Air bending is a commonly used method for sheet-metal forming. However, several challenges exist around the bending behavior of materials with poor global formability, that are difficult to study using conventional bending test methods, and thus may not be fully understood. In this study, nine thermomechanically rolled steel grades with various strengths and ductility properties are bent using three different punch radii. The strain distributions on the outer surface are measured using Digital Image Correlation (DIC). The relationships between the strain distribution, peak strain, and total strain (area under the strain distribution curve) are determined. The total strain is observed to be independent from the peak strain and the shape of the strain distribution. The total strain is found to depend on the bend angle and sheet thickness. An analytical formula for approximating the total strain is derived. Potential for further approximations of the total strain, strain distribution and bend shape are discussed. </jats:p>

Topics

• impedance spectroscopy
• surface
• strength
• steel
• bending flexural test
• forming
• ductility