SBIR-STTR Award

Composite aircraft structures present significant inspection challenges to most NDI methods. Most widely used NDI modalities, e.g. visual inspection and coin tap, have little or no relevance to composite aircraft. These are typically qualitative techniques that are difficult to replicate, and depend on subjective interpretation by the inspector. Visual inspection, which is still widely used for metal airplanes, is largely ineffective in composites, since most problems that occur leave no indication at the surface. Single point ultrasonic inspection (A-scan) is time prohibitive and its effectiveness relies on operator skill. In the proposed Phase I program, we will address the shortcomings of current thermography technology, in order to develop an automated, large scale NDI system suitable for on- aircraft inspection of large composite structures at a NAVAIR depot. The system we propose will build on the existing thermography knowledge base but, if successful, will address a significantly greater thickness range than current technology allows. It will also reduce the total cost of inspection because of substantial time savings with the added benefit of improved reliability of fidelity of depot level inspections.

Benefit:
Although this proposal has focused primarily on aerospace applications, significant market opportunities exist in the solar and wind energy industries where similar large area inspection requirements apply (composite wind turbine blades range from 100 to 150 ft. in length). Opportunities also exist in the automotive industry, where the growing use of composites presents new QA and NDE challenges.

Keywords:
TSR, TSR, Automated, modulated, NDI, multiscale, KC-130J, Composite structures, Thermography

Automated, rapid, non-destructive inspection of large scale composite structures is an ongoing challenge for just about every NDI technology currently deployed in the aerospace, power generation, wind energy, and automotive industries. Both hardware and software limitations have dictated the level of inspection throughput, accuracy and reliability. In Phase I, TWI developed and demonstrated feasibility of a novel technique to thermographically inspect large composite areas at a large standoff without expected trade-off in performance. Using a sophisticated signal processing scheme and projected, modulated optical excitation, we demonstrated detection of subsurface features in composite materials at a working distance of 45 feet from the target. The results were comparable to (and in some cases better than) results from commercial flash thermography systems operating at close range. In Phase II, we shall build on the Phase I program and develop a commercially viable solution (prototype) - LASLAT (Large Standoff / Large Area Thermogrpahy) offering flexibility so it can be readily adapted to a broad range of applications requiring rapid large area NDI with a focus on wings of C-130J family of aircraft operated by our military.

Benefit:
Our proposal was formulated based on input from current and prospective customers in government and private aerospace manufacturing, service, and R&D, including Boeing, Lockheed Martin, Navy, Air Force, NASA, commercial airline carriers, and military NDE personnel. These customers indicated a high degree of interest in a system capable of rapidly inspecting large composite structures faster and more cost-effectively whilst incorporating the advanced capabilities of pulsed thermography systems they are using on other applications. In addition, they are also looking for a solution allowing access to confined spaces and operation in flammable fuel vapor environments. After initial launch of a LASLAT system, we expect our solution will be implemented for the C-130 family of aircraft operated by the US Navy and US Air Force. Based on current projections, a total investment of

Keywords:
thermographic, Infrared, Wing, NDT, NDI, C-130, Composite, Large