US 11,867,576 B2
Optical cable
Kinzo Kishida, Kobe (JP); Ahmad Riza Ghazali, Kajang (MY); and Mohamad Faizal Bin Abd Rahim, Kajang (MY)
Assigned to PETROLIAM NASIONAL BERHAD (PETRONAS), Kuala Lumpur (MY)
Appl. No. 17/642,618
Filed by PETROLIAM NASIONAL BERHAD (PETRONAS), Kuala Lumpur (MY)
PCT Filed Sep. 11, 2020, PCT No. PCT/MY2020/050084
§ 371(c)(1), (2) Date Mar. 11, 2022,
PCT Pub. No. WO2021/049929, PCT Pub. Date Mar. 18, 2021.
Claims priority of application No. PI 2019005315 (MY), filed on Sep. 13, 2019.
Prior Publication US 2022/0341798 A1, Oct. 27, 2022
Int. Cl. G01L 1/24 (2006.01); G01D 5/26 (2006.01); G01H 9/00 (2006.01)
CPC G01L 1/242 (2013.01) [G01D 5/268 (2013.01); G01H 9/006 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An optical cable for measuring a stress wave generated by vibration of a measurement target, the optical cable comprising:
a stress wave detection optical cable including an optical fiber provided at an axial part, a plurality of first steel wires helically wound so as to surround the optical fiber, and a flexible material surrounding the optical fiber and the plurality of first steel wires; and
second steel wires different from the first steel wires, wherein
the stress wave detection optical cable and the second steel wires are helically wound to form one annular body as a whole, and
a winding angle (α) of the stress wave detection optical cable with respect to an axis of the optical cable is a function of a strain ratio parameter (A), wherein the strain ratio parameter (A) is a function of two Lamé constants (λ, μ),
each of said Lamé constants (λ, μ) being a function of an elastic moduli (E) and a Poisson's ratio (ν) of the flexible material and a cable surrounding body surrounding the optical cable at a location where the optical cable is placed;
wherein:

OG Complex Work Unit Math