Hill Engineering Blog

Case Study: cold hole expansion process modeling

Cold hole expansion (Cx or cold expansion for short) of fastener holes is a technique that has been widely used in the aircraft industry to improve the fatigue performance of structural components. The cold hole expansion process introduces compressive residual stress near the vicinity of the hole that slows crack growth and can significantly improve fatigue performance.

Our latest Case study focuses on process modeling using finite element analysis for the prediction of residual stress from cold expansion of fastener holes. A process model is developed to simulate the expansion of the hole due to the mandrel pull-through operation, and the resulting hoop residual stress after elastic recovery of the material is presented.

Follow the link above to read the full case study write-up. If you have any further questions about the study, about cold hole expansion, or residual stress measurements in general, feel free to contact us.