IMPACT AND VIBRATION DETECTION IN COMPOSITE-MATERIALS BY USING INTERMODAL INTERFERENCE IN MULTIMODE OPTICAL FIBERS

An optical fiber sensor based on the intermodal interference principle is integrated in a composite material to detect impacts and vibration s. Six fibers are integrated at the top of a carbon/epoxy composite pa nel so as to form a grid into the structure. Spectral and temporal res ponses to impacts and acoustic vibrations of the sensor are compared w ith a piezoelectric accelerometer. The tests proved the facility of in tegration and the high sensitivity of the device. The location of impa cts is performed with this arrangement by measuring the arrival times of the front waves to the fibers. (C) 1996 Optical Society of America