AEROSPACE/MILITARY APPLICATIONS FOR THEIR HIGH STRENGHT-TO- DENSITY AND STIFFNESS-TO-DENSITY RATIOS.

AEROSPACE/MILITARY APPLICATIONS FOR THEIR HIGH STRENGHT-TO- DENSITY AND STIFFNESS-TO-DENSITY RATIOS. THESE COMPOSITES WILL BE SUBJECT TO DAMAGE AND ENVIRONMENTALLY AGED IN USE. REPAIR OF LAMINATED COMPOSITES BY RESIN INJECTIONS IS HINDERED BY THE DIFFICULTY OF FLOWING RESIN INTO THE DELAMINATION. PREVIOUS WORK HAS SHOWN THE EFFIECIENCY OF ULTRASONIC FLOW PROMOTIONM IN A WIDE VARIETY OF SYSTEMS, INCLUDING THERMOPLASTIC MATERIALS AND VARIOUS RESIN SYSTEMS.THE ULTRASONIC EFFECT IS THAT OF OF FRICTION REDUCTION REDUCTION BETWEEN THE FLOWING MATERIAL AND THE ADJACENT SURFACE, AS WELL AS TRANSIENTLY REDUCED VISCOSITY AND SURFACE TENSION OF THE FLUID MATERIAL. THE PHASE OBJECTIVE OF THIS PROPOSED WORK IS TO DEMONSTRATE THE FEASABILITY OF APPLYING ULTRSONIC FLOW PROMOTION TO IMPROVE RESIN INJECTIONINTO DELAMINATIONS IN DAMAGED COMPOSITES, AS DEMONSTRATED BY FLOW MEASUREMENT DURING ULTRASONIC ACTIVATION TO PRELIMINARY ESTABLISH ULTRSONIC OPERATING PARAMETERS, FOLLOWED BY REPAIR OF DAMAGED COMPOSITE PANELS SUPPLIED BY THE NAVY. THE PANEL SAMPLES WILL BE DELIVERED TO THE NAVY FOR EVALUATION.