In-situ imaging approach for investigating residual stress formation in rolling process

In-depth experimental observations of the evolution of residual stress in response to a physical field during the manufacturing process are few. Hence, an in-situ imaging setup is designed to record the workpiece material deformation history during a mechanically dominant rolling process. A novel mechanics-enriched digital image correlation approach that enables the reconstruction of mechanical fields during the rolling process is proposed herein. Accordingly, a correlation between the mechanical effect and resulting residual stress is formulated. The residual stress evolution can be reproduced via inclusion theory based on in-process mechanical messages. This process is categorised into three phases based on their governing effects, i.e. the build-up phase (induced by the squeezing effect of the roller), loading phase (due to contact), and recovery phase (after unloading), to facilitate understanding regarding the residual stress formation mechanism. The methodology used in this study is validated via artificial tests and comparisons between predicted and measured residual stresses after the rolling process.