CONDUCTIVITY METER FOR GRAPHITE EPOXY

THE ELECTRICAL CONDUCTIVITY OF GRAPHITE EPOXY COMPOSITE MATERIAL IS A FUNCTION OF THE RELATIVE ORIENTATION OF THE APPLIED FIELD AND THE FIBER DIRECTION FOR UNIDIRECTIONAL MATERIAL. PRIOR ATTEMPTS AT NONCONTACT, NONDESTRUCTIVE ELECTROMAGNETIC METHODS OF CONDUCTIVITY MEASUREMENT HAVE NOT BEEN FULLY SUCCESSFUL DUE TO LOW LEVELS OF SIGNAL OR IMPROPER ORIENTATION OF THE ELECTROMAGNETIC FIELDS. TWO PROPRIETARY APPROACHES TO OVERCOMING THE DEFICIENCIES HAVE BEEN FORMULATED; ONE AT MICROWAVE FREQUENCIES USING REFLECTIVITY MEASUREMENT AND THE OTHER AT LOWER FREQUENCIES EXPLOITING THE IMPEDANCE CHANGES AND MICROCOMPUTER SUPPORT OF A SPECIALLY DESIGNED, CALIBRATED EDDY CURRENT PROBE. IT IS PROPOSED THAT BOTH THESE APPROACHES BE EXPERIMENTALLY STUDIED IN DETAIL SO THAT THEIR FEASIBILITY CAN BE DETERMINED, THEIR RELATIVE COST EFFECTIVENESS DETERMINED AND THE DATA BASE AND APPROACH TO PROTOTYPE FIELD USABLE SYSTEM DESIGN BE GENERATED.