ELECTRICAL AND LUMINESCENT EFFECTS OF FRACTURE IN SOME FIBER REINFORCED PLASTICS.

Abstract : Structural fiber reinforced plastics under applied stress exhibit an internal microcracking process that often begins at small fractions of the ultimate strength of these materials and with increasing load complete fracture of a specimen occurs. This process is a complex combination of fiber fracture, small cracks in the matrix phase and fiber-matrix interfacial debonding, depending on the stress level, materials involved and other factors. There is a current need for additional means of detecting and measuring this process as it occurs. The report presents experimental evidence that such microcracking in these materials produces measurable electrical effects and in some cases the emission of visible light. Detection and measurement of these effects may provide new experimental tools for the investigation of the microcracking process in fiber reinforced plastics. (Author)