Standard Inline Non-destructive Determination of Prepreg Resin Impregnation Level

ABSTRACT: Incomplete and inconsistent impregnation of fiber beds in composite material manufacture jeopardizes the performance of multiple aircraft platforms and substantially increases acquisition and sustainment costs for the Air Force. Current test methodologies are inadequate to address this problem as they cannot be conducted during manufacture, exhibit poor accuracy and repeatability, and are destructive to the material under test. Nokomis will address this need through development of a standard test method that applies air-coupled ultrasonic waves to assess LOI by determining the concentration of remaining air within produced material. Multiple quantitative indicators will be extracted from each test and analyzed to return highly accurate and repeatable LOI assessments. Measurement of acoustic energy reflected, transmitted, scattered, and absorbed will be combined via data fusion to provide LOI with better than +-1% accuracy. The developed standard test method will be inserted into production following partial impregnation on a rastering frame, enabling 100% material inspection and providing real-time feedback on material consistency and performance criteria. This Phase I effort will develop, validate, and standardize the LOI assessment test and produce preliminary test and technology transition documents that facilitate Phase II prototyping and broad industry acceptance. BENEFIT: Resin impregnated composites are vital to the performance specifications of modern complex aircraft such as those employed by the Air Force. Manufacturing efficiency is critical to acquisition and sustainment of projected needs. The standard test method developed under this program will substantially improve manufacturing efficiency by providing accurate and reliable LOI assessments, ensuring that all delivered material meet Air Force specifications. As Nokomis"proposed test methodology can be applied inline, real-time results can be obtained on material LOI consistency over multiple production runs and across the manufactured roll. Manufacturers can utilize real-time assessments to make immediate adjustments, reducing the quantity of material produced below specification. This results in overall material, time, and labor cost reduction that facilitates the acquisition and sustainment of Air Force aircraft. While development efforts will focus on addressing Air Force needs, Nokomis anticipates that the developed technology will provide similar benefits to other Department of Defense (DoD) agencies that employ similar prepreg composite materials, achieving broad cost reductions across multiple programs. Nokomis will additionally pursue commercial markets such as domestic aerospace firms which utilize prepreg composites in modern airframes.