FIBRE BRAGG SENSORS COMPARED WITH ELECTRICAL STRAIN GAUGES FOR USE IN FORCE MEASUREMENT - PROSPECTS AND POTENTIALS

Thomas Kleckers
Abstract:
This article deals with the technical properties of fiber Bragg gratings with regard to their use as the strain-sensitive element in force transducers.
Electrical strain gages are widely used in modern, precise force transducers. The electrical strain gage provides both outstanding technical properties and cost-effectiveness.
Besides the electrical strain gage, the measurement principle of fiber Bragg-based sensors has recently become established. First applications in experimental mechanics have shown that this technology offers a lot of potential.
Optical strain gauges are available on the marked since one year and are proofed in many applications.
These sensors are mainly based on so-called fiber Bragg gratings. Such a Bragg grating uses a great many reflection points at regular spacing. At each of these points, part of the radiated light is reflected. The reflected light interferes (constructive interference) and generates a reflection peak. This peak shows a characteristic wavelength which is dependent on the spacing of the reflection points.
The following sketch shows a Bragg grating in a fibre and its influence on the spectrum of the transmitted and reflected light.
This article presents the properties relevant to use in the manufacture of transducers such as:
- Creep
- Temperature behaviour
- Drift
- Electromagnetic compatibility
and others and compares them with the properties of electrical strain gages.
Keywords:
optical strain measurement, Fibre-Bragg gratings, optical force measurement
Download:
IMEKO-WC-2009-TC3-144.pdf
DOI:
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Event details
Event name:
XIX IMEKO World Congress
Title:

Fundamental and Applied Metrology

Place:
Lisbon, PORTUGAL
Time:
06 September 2009 - 11 September 2009