STRAIN SENSOR UTILIZING OPTICAL FIBER AND DEFORMATION- MONITORING SYSTEM USING THE STRAIN SENSOR

摘要

PROBLEM TO BE SOLVED: To detect deformation and collapse of inclined faces of mountainous regions, cliffs or the like, deformation and collapse of structures, etc., by detecting strains of strain detection points with the utilization of the fact that a quantity of penetrating light increases or decreases because of a change in radius of curvature of a curved part of an optical fiber set to the strain detection point by the strain. ;SOLUTION: A strain sensor 1 is constituted of an optical fiber 2 arranged in a strain state, a housing 4 having a curved part 3 of the optical fiber 2 inside, a leaf spring 5 elastically supporting the curved part 3 formed in the housing 4, and the like. The optical fiber 2 balances with the leaf spring 5 and is arranged in the strain state while being pulled with a constant tension to prevent a radius of curvature from changing at the other time than when a strain is brought about to a strain detection point. A light source 2a is connected to one end of the optical fiber 2, and a light receiving element 2b is connected to the other end of the optical fiber. The light receiving element 2b detects an increase/decrease of a quantity of penetrating light of light from the light source 2a, detects the change in radius of curvature of the curved part 3 of the optical fiber 2 where the strain is generated, thereby detecting the presence/absence of generation of the strain and a direction of the strain.;COPYRIGHT: (C)2000,JPO