ABSTRACT
One of the most powerful applications of quantitative ultrasonic techniques to composites lies in the ability to characterize microstructural composition. For polycrystalline metal samples, bulk defects are of primary importance in assessing the structural integrity of completed parts. C-scan techniques have proven to be successful in identifying these defects. While this capability is of importance for composites as well, one must be concerned with a wide array of more subtle defects. Composites achieve their desired properties through engineered microstructures with clearly defined fiber distributions and orientations. Deviations in the microstructure can result in degraded material properties which can adversely affect performance. Fortunately, there is a great deal more information present in an ultrasonic signal than there is in a conventional C-scan. This capability is coupled with composite micromechanics theory providing a quantitative means of microstructural feature characterization. The test method utilizes a set of transducers imbedded inside a rolling mill.
