Title:
STRAIN DETECTING SENSOR
Document Type and Number:
Japanese Patent JPH04138307
Kind Code:
A
Abstract:
PURPOSE:To improve measuring accuracy by fixing an optical fiber at a constant interval, and providing the freedom of lateral movement for the optical fiber between the fixing points. CONSTITUTION:Under the state wherein a spacer 2 is made to elongate into the specified length in an elastic region, and optical fiber 1 is inserted in a groove 3. After the fiber is fixed with bonding agent 4 at a constant pitch, the tension of the spacer 2 is released. Then, required compression strain is applied on the optical fiber 1 with the elastic restoring force of the spacer 2. Strain sensors 10 and 10' are attached to the upper and lower sides of a pipe 11 which is provided on the ground or mebedded in the ground. The deflections of the pipe 11 in the upper and lower directions are detected. Namely, when the pipe 11 is deflected from the linear state, the (a) part of the sensor 10 and the (b) part of the sensor 10' undergo the compression strains in the respective axial directions. Therefore, the spacer 2 is deflected at, e.t. the (a) part. The optical fiber is displaced in the direction where the freedom in the lateral movement is present and curved. The radius of curvature of the optical fiber between the fixing points at this time is always constant when the amount of strain is equal. Therefore, the amount of strain of the pipe can be accurately detected based on the amount of optical transmission loss whose relation to the amount of strain is constant.
Inventors:
MURATA YOSHIKAZU
YAMAGUCHI MASAYOSHI
YAMAMOTO JUN
FUSHIDA TAKASHI
YAMAGUCHI MASAYOSHI
YAMAMOTO JUN
FUSHIDA TAKASHI
Application Number:
JP26275390A
Publication Date:
May 12, 1992
Filing Date:
September 28, 1990
Export Citation:
Assignee:
SUMITOMO ELECTRIC INDUSTRIES
NIPPON STEEL CORP
NIPPON STEEL CORP
International Classes:
G01L1/00; G01B11/16; G02B6/00; (IPC1-7): G01B11/16; G01L1/00; G02B6/00
Attorney, Agent or Firm:
Bunji Kamata (2 outside)