Triangular Optical Cable for Precise Structural Deformation Measurement

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Solution Overview

Problem

Existing optical cables for measuring structure deformation and temperature require angular orientation adjustments, which complicates the measurement process and precision.

Innovation Solution

An optical cable with a triangular arrangement of optical elements, held in contact by a sheath, ensuring constant orientation and precise positioning, allowing for accurate deformation and temperature measurement by emitting test signals and analyzing frequency spectra.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical fibers are distributed around the periphery of a cylindrical armature, then measurement of curvatures is enabled independently of torsion or axial traction, but angular orientation (Ψ) of the fibers must be taken into account, complicating the measurement process

Engineering Contradiction:
Improvemeasurement independence from torsion and axial tractionVSAvoidangular orientation accounting requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from a symmetric cylindrical armature arrangement to an asymmetric triangular arrangement of optical elements. The triangular configuration with optical elements at vertices and midpoints of sides creates inherent angular orientation markers that eliminate the need for complex angular orientation accounting while maintaining measurement reliability independent of torsion and axial traction.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent adds angular orientation information to the measurement dimension by positioning optical elements at specific angular locations (vertices and midpoints of triangular sides). This dimensional addition of angular markers allows the system to maintain simplicity in measurement processing while preserving the reliability benefit of being independent from torsion and axial traction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If optical elements are arranged to form a triangular cross section, then constant orientation throughout the cable is achieved, but manufacturing precision of element positioning becomes critical

Engineering Contradiction:
Improveconstant orientation of optical elementsVSAvoidpositioning precision of optical elements
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The triangular arrangement of optical elements with specific positioning at vertices and midpoints of sides creates a self-aligning structure. The geometric configuration inherently maintains constant orientation throughout the cable, and the positioning can be achieved through standardized manufacturing processes without requiring extremely tight tolerances, as the triangular geometry itself provides the orientation stability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies different positioning requirements to different locations in the triangular arrangement. Optical elements at vertices and midpoints of sides are positioned to create the triangular configuration, with the understanding that standard manufacturing tolerances are sufficient for this geometric arrangement. The local positioning precision required is moderate rather than extreme, as the overall triangular geometry provides the constant orientation function.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If optical elements are held in contact by the sheath, then precise relative positioning is achieved, but the sheath material must be transparent to ambient light for proper optical function

Engineering Contradiction:
Improverelative positioning precision of optical elementsVSAvoidsheath material transparency requirement
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The sheath material is designed with different properties in different regions: it is transparent to ambient light in the regions where optical elements are positioned and held in contact, while potentially having different optical properties in other regions. This localized quality assignment allows the sheath to fulfill both the positioning function and the optical transmission function without requiring the entire sheath to be uniformly transparent.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sheath acts as an intermediary structure that simultaneously provides mechanical support for precise positioning of optical elements and allows optical signals to pass through. The transparency of the sheath material to ambient light serves as a mediator property that enables both the positioning function and the optical function to coexist without interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The cable provides precise and consistent orientation along its length, enabling accurate deformation and temperature measurements by maintaining optical elements in contact, enhancing measurement precision and ease of installation.

Implementation Method 1

Each fiber is provided with photo-inscribed Bragg gratings distributed along the fiber at regular intervals

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 2

Each fiber is provided with photo-inscribed Bragg gratings distributed along the fiber at regular intervals

Methodology Applied
Scientific EffectBragg grating reflection: Bragg Diffraction

Data Source

PatentEP2795386B1Optical cable adapted for measuring a deformation or a temperature
Publication Date: 2017.07.26 ACOME SOC COOP & PARTICIPATIVE SOCIE
  • EP2795386B1 patent drawingFigure 1~2
  • EP2795386B1 patent drawingFigure 3
  • EP2795386B1 patent drawingFigure 4~5

AI summary

The invention relates to an optical cable (10) comprising an optical core (20) and a sheath (30) surrounding the optical core (20), in which the optical core (20) is constituted by a number N of optical elements (21-23), N being defined by (I), where n >= 2, optical elements (21-23) being arranged with respect to one another in such a way as to confer upon the optical core (20) a transverse section of general triangular shape, the optical elements being held in contact with one another by the sheath, and in which the sheath (30) exhibits an external surface having three plane longitudinal portions (31-33) each extending along a side of the triangle. The optical cable is particularly adapted to be positioned against a structure so as to measure a deformation or a temperature of the structure.