Advanced Non-Destructive System to Characterize Subsurface Residual Stresses in Turbo-machinery Components
Navy SBIR FY2015.2

Sol No.: Navy SBIR FY2015.2
Topic No.: N152-091
Topic Title: Advanced Non-Destructive System to Characterize Subsurface Residual Stresses in Turbo-machinery Components
Proposal No.: N152-091-0814
Firm: X-wave Innovations, Inc.
555 Quince Orchard Road
Suite 500-B
Gaithersburg, Maryland 20878
Contact: Dan Xiang
Phone: (240) 364-6018
Web Site:
Abstract: Surface enhancement methods, such as shot peening (SP), laser shock peening (LSP), and low-plasticity burnishing (LPB), can introduce beneficial near-surface compressive residual stress and significantly improve the fatigue resistance and foreign object damage tolerance of aerospace components such as superalloy turbine fans, disks, and integrally bladed rotors (IBR). Residual stress, however, relaxes with usage. To predict the remaining useful life (RUL) for those critical components, accurate and reliable residual stress profile data in the subsurface region are required. X-ray diffraction (XRD) is the only acceptable nondestructive evaluation (NDE) method for residual stress assessment, which is limited to an extremely thin (less than 20 µm deep) surface layer. Alternative NDE methods, including the most promising Eddy Current Conductivity Spectroscopy (ECCS) and Surface Acoustic Wave (SAW) technology, have been studied for years, but none of them can provide reliable subsurface residual stress assessments. To address this critical need, X-wave Innovations, Inc. (XII) with Lockheed Martin (LM) Cooperation, propose to develop a novel NDE tool for subsurface residual stress measurements in surface-enhanced aerospace structural components. In the Phase I program, we will focus on the prototype system development and demonstrate the feasibility of the proposed approach. For the Phase II program, we will refine the prototype system with improved hardware and software and validate its performance for subsurface residual stress measurements. For the Phase III program, we will focus on the optimization of the system performance, as well as the transitioning of the developed technology.
Benefits: The proposed subsurface residual stress measurement system should have many market applications in different industries such as the air and space, defense and energy sectors. Customers for this technology should include the US government agency, e.g., DOD, NASA, DOE, etc, and commercial companies such as Lockheed Martin, Boeing, GE, etc. The proposed research provides a means for cost-savings of maintenance as well as improvement of a material system’s performance. Such a NDE technique will benefit the enhancement of the lifetime and durability and the reduction of failure risk of those systems. This new NDE system could significantly extend the service life of air and space crafts, reduce maintenance costs, and protect the platforms’ and crews’ safety.