Prediction of Residual Stress in Acoustoplastically Deformed Copper and Titanium Plates Using the Shear Birefringence Method

This study presents a systematic investigation into the prediction of residual stresses in acoustoplastically deformed copper and titanium plates using a shear birefringence method. A total of 42 plastically deformed regions were created on each metal plate using a custom acoustoplastic setup. Each region was generated through a unique combination of three process parameters: static downforce, applied ultrasonic power, and the rotational speed of the sonotrode. The induced residual stresses were non-destructively evaluated using a shear birefringence technique, enabling full-field stress mapping of the plastically deformed zones. The measured residual stresses were then correlated with the acoustoplastic input parameters to understand their individual and combined influence on stress distribution. The results highlight clear trends in how ultrasonic energy and mechanical parameters contribute to stress relaxation and redistribution in both copper and titanium. This work provides valuable insights into tailoring acoustoplastic forming processes for stress-engineered materials and supports the broader application of ultrasonic-assisted manufacturing in advanced metal forming.