Nondestructive Evaluation of Changes in Mechanical Properties in Carbon-Carbon Composites during Processing

In this work, changes in the mechanical properties of carbon-carbon composites during processing are studied using nondestructive characterization techniques. Ultrasonics and radiography are used to measure the local stiffnesses in carbon-carbon panels after each stage in the processing cycle. The degree of material inhomogeneity (as measured by the standard deviation in the local moduli) was monitored throughout the fabrication process. The nondestructively measured stiffnesses were compared with direct mechanical measurements to assess the viability of the technique.