Development of an Inverse Routine to Predict Residual Stresses in the Material Based on a Bending Test

Bending with unloading and reverse bending are the dominant material deformations in roll forming and hence property data derived from bend tests could be more relevant than tensile test data for numerical simulation of the roll forming process. Recent investigations have shown that residual stresses affect the material behaviour close to the yield in a bending test. So, Residual stress introduced during prior steel processing may affect the roll forming process and therefore needs to be included in roll forming simulations to achieve improved model accuracy. Measuring the residual stress profile experimentally is expensive, difficult, time consuming and has limited accuracy. Analytical models are available that allow the determination of residual stress. However, for this detailed information about the pre-processing conditions is required; this information is generally not available for roll forming materials. The main goal of this study is to develop an inverse routine that generates a residual stress profile through the thickness of the material based on pure bend test data.