Volume 1, Issue 3 (March 2004)
A Test Method to Determine the Fiber and Void Contents of Carbon/Glass Hybrid Composites
Hybrid composites are increasingly being used in infrastructure, oil recovery, and aerospace applications. These hybrids generally combine two different types of fibers to reinforce the resin, thereby gaining some of the advantageous properties of both fibers. Typically, carbon and glass are used since this combines the high performance of the carbon with the low cost of the glass. The performance of such materials depends on a number of factors, including the mix ratio of the fibers as well as the fiber and void contents. At present, there is no simple way to determine these features. Although a number of techniques exist for measuring such parameters when only a single reinforcement is present, extension of these methods to hybrids can be difficult. The work here, however, shows that one technique, the burn off test in ASTM D 3171-99, can be extended to characterize carbon/glass hybrids. To verify this procedure, data were obtained for a series of samples with known compositions, and the agreement was excellent. The proposed method has minimal equipment requirements and provides a simple way to obtain important compositional information.