Project Lead: General Dynamics Electric Boat
Project Start: April 2013
The U.S. Navy and General Dynamics Electric Boat (GDEB) have a joint initiative to reduce the construction cost of VIRGINIA class submarines (VCS). The Navy ManTech Program is participating in this initiative with specific focus on improving manufacturing processes for ship construction.
The goal of this project is to achieve a 20% reduction in inspection costs for hull butt welds by implementing, where practical, the use of Phased Array Ultrasonic Technology (PAUT)/Time of Flight Diffraction Techniques (TOFD) in lieu of Radiography Techniques (RT) and conventional Ultrasonic Technique (UT). GDEB recognizes the significance of UT to reduce the cost of submarine construction and has increased usage of conventional UT in lieu of RT for the recent VCS. GDEB has determined that additional savings can be realized by exploiting the more advanced next generation PAUT/TOFD technology. GDEB will be supported in this effort by EWI and the Naval Surface Warfare Center Carderock Division (NSWCCD).
The project will be executed in two phases. During the first phase, the project team will determine the technical feasibility of inspecting hull butt welds with PAUT/TOFD technology. The second phase will compare the effectiveness of conventional UT vs. PAUT inspections on as-welded VCS hull butt welds at Quonset Point. The main focus of this project is to determine feasibility of PAUT/TOFD as a replacement for conventional UT in order to reduce VCS inspection costs by upwards of 20%.
This technology, once implemented, could potentially save an estimated $541K per VCS Hull. These savings will result from less surface preparation or grinding of weld reinforcement, the potential for automation thereby increasing inspection speeds, and the potential for reducing the need for radiography and the risks associated with ionizing radiation. While the project focuses specifically on improvements benefiting the VCS, the same benefits described here can accrue to all U.S. Naval ships.