The mechanical behavior of optical fiber sensor embedded within the composite laminate

Mechanical behavior, such as tensile and fatigue strength, of the optical f iber sensor embedded within the composite laminate was investigated. Tensil e and fatigue tests were performed to evaluate the static and fatigue chara cteristics of optical fibers embedded within three types of laminated compo site specimens, [0(6)/OF/0(6)](T), [0(2)/90(4)/OF/90(4)/0(2)](T) and [0(3)/ 90(3)/OF/90(3)/0(3)](T). The initiation of damage and fracture of the optic al fiber were detected by observation of the intensity drop-off of laser si gnal transmitted through the optical fiber during test. Experimental result s showed that the fatigue strength of optical fiber embedded within the cro ss-ply laminate is much lower than the fatigue strength of optical fiber wi thin the unidirectional ply laminate. It was also found that the optical fi ber embedded within unidirectional ply laminate fractured due to the fatigu e damage accumulation of internal defects of optical fiber itself. However the optical fiber embedded within the cross-ply laminate fractured due to t he growth of transverse matrix crack of host composite laminate. (C) 1999 K luwer Academic Publishers.