Vibration Stress Relief

ABSTRACT: To perform on-airplane weld repairs of the F-22 titanium frames and forward and aft booms is highly desired, but currently not practical due to the required high temperature thermal stress relief process. An alternative is to apply the vibration stress relief scheme, which is increasingly used in heavy industry. The major problem associated with the vibration stress relief is its repeatability and controllability. Thus, the US Air Force is seeking a repeatable, vibration-based stress relief technology for on-airplane weld repairs of major structural components. In this proposal, X-wave Innovations, Inc. (XII) outlines a Portable Ultrasonic Stress Reliever (PUSR) for highly efficient, controllable and repeatable residual stress relief in weldments of airplane structural repairs. In the Phase I program, XII will prototype a PUSR system and demonstrate the feasibility of this approach for highly efficient, repeatable residual stress relief in weldments. For the Phase II program, XII will focus on refining the prototype system design and development with improved hardware and software. For the Phase III program, XII will focus on collaborating with our commercial partners to improve and package the PURS technology into to a turnkey commercially-available system. BENEFIT: The proposed PUSR system has many market applications in different industries such as the air and space, surface and underwater vehicles, automobile, and power plants. The total market will increase in the future because the residual stress relief in weldments is invaluable for keeping the structure dimensions, preventing damage initiation, and extending the service lift of many important material systems. The proposed research provides a great support for effectively relieving the local residual stress of a large structure without the need to put the entire structure at resonance. This local residual stress relief technique is more repeatable and accurate than any other vibration stress relief approach currently used in the field. Therefore, the market for the PUSR system is huge.