Ballistic Missile System Composite Materials and Structures - NDE for Porosity (MSC P1F46-411)

Pulse echo ultrasonic waveform measurements will be used for NDE of composites for quantification of porosity. A software based on statistical and mathematical methods will be developed for identifying the time regions of interest (the echo region), denoising the signal and analyzing the processed signals at a cluster of stations (in frequency domain) using multivariate regression analysis. The objective is to reduce the scatter in measured attenuation. Data will be obtained from a selected number of samples from composites of interest (those processed using automated fabrication methods, such as resin transfer molding, are of greatest concern because of expected large porosity content) and the usefulness of the NDE method and data processing methodology will be demonstrated. Correlation with measured porosity with attenuation (or attenuation maps) will be performed based on the attenuation at a single frequency or the rate of change of attenuation with frequency in the range where the data analysis will indicate the region of highest feature relevance. Refinement of the technology is the goal of Phase II along with the detail of cost of implementation of the NDE method.