Abstract

This study illustrates the applicability of attached and embedded fiber-optic sensors in fracture-mechanics problems. Fracture studies of metals and nonmetals in the laboratory are important in predicting and preventing failures of machines and structures. Within the elastic domain, crack propagation in a material is governed by the stress-intensity factor, which completely defines the stress field near the crack tip. The experimental results for the mode I stress-intensity factor, obtained with single-edge notched specimens fabricated from aluminum, compare well with theoretical predictions. This indicates that the mode I stress-intensity factor can be accurately determined by choosing the proper orientation and size of the single-mode fiber-optic sensor. The advantage of this technique is that it can be effectively used to measure subsurface strains in thick cracked bodies, because the fiber can be easily embedded during the fabrication process.

© 1990 Optical Society of America