STRUCTURE STRAIN MONITORING METHOD AND ITS MONITORING DEVICE

摘要

PROBLEM TO BE SOLVED: To make correctable the light loss caused by the change of the environmental temperature or the bending of a optical fiber sensor cable by installing multiple optical strain sensors on a structure, and calculating the strain quantity with a calibration curve table indicating the relation between the light loss of the optical fiber strain sensor and strain, prepared in advance. ;SOLUTION: When a pipeline is to be measured by an optical fiber strain sensor 2 as a structure 1, multiple optical fiber strain sensors 2 are installed axially symmetrically in the peripheral direction at prescribed intervals. The transmission paths of multiple optical fiber strain sensors 2 are switched by an optical coupler 8 and/or a light switch 9, and the transmitted light passing through each optical fiber strain sensor 2 is measured. The measured light of each optical fiber sensor 2 is referred to a calibration curve table storing the relation between the light loss of each optical fiber strain sensor 2 and strain obtained in advance to determine the strain quantity of the structure 1, and the strain of the structure 1 is monitored.;COPYRIGHT: (C)1999,JPO