Fatigue destruction advance method of detection null of FRP

摘要

PURPOSE: To detect the fatigue failure of a fiber-reinforced plastic(FRP) member in advance by detecting the variation of the permeability of a magnetic substance arranged in the FRP member. ;CONSTITUTION: When a high-frequency current is supplied to a first and second excitation coils 4a and 4b from a power source 7 for high-frequency current, lines of magnetic force indicated by the dotted line A form a closed magnetic path through an FRP member 1. The electromotive force induced by the lines of magnetic force is detected by means of second detection coils 5a and 5b and measured as a mutual inductance by means of a detector 8. This inductance varies depending upon the magnitude of the compressive stress, therefore, the permeability of amorphous wires arranged in the member 1. Therefore, the compressive stress of the amorphous wires arranged in the member 1 can be measured indirectly by measuring the inductance.;COPYRIGHT: (C)1993,JPO&Japio