PROCESSING RESIN MATRIX COMPOSITES USING HIGH INTENSITY ULTRASOUND.

Experiments were performed to demonstrate several aspects of the use of high-intensity ultrasound in the place of heat and pressure as the sole source of energy in processing graphite/epoxy composite laminates. Self-limiting of the sonic energy absorption was observed in small specimens as curing of the epoxy proceeded, and fully cured, well consolidated, and pore-free material was produced. Extension to larger specimens requires consideration of how to obtain the desired spatial distribution of sonic energy in the metal form which supports the composite. A special case occurs when the composite part has a nonuniform thickness over its area. A method was developed for uniform consolidation of a 76-mm square laminate that was 12-plies thick over half its area and 20-plies thick over the other half, and methods were conceived for extending this processing to full-scale production parts.