Related Experiment Video
Updated: Jul 6, 2026
06:17
Production of a Strain-Measuring Device with an Improved 3D Printer
Published on: January 30, 2020
Intracore fiber bragg gratings for strain measurement in embedded composite structures
Applied Optics
|March 22, 2008
Summary
Fiber Bragg grating (FBG) sensors measure strain in composite materials by detecting changes in reflected light wavelength. These sensors are valuable for self-monitoring composite structures under load and varying temperatures.
Area of Science:
- Materials Science
- Optical Engineering
- Structural Health Monitoring
Background:
- Fiber Bragg gratings (FBGs) are inscribed on photosensitive fiber cores.
- FBGs are sensitive to strain and temperature changes, which affect the Bragg-reflected wavelength.
- FBG sensors offer immunity to source intensity variations and losses.
Purpose of the Study:
- To investigate the use of FBG sensors for strain measurement in composite specimens under load.
- To analyze the effects of temperature on FBG sensors used in composite structures.
- To explore the application of embedded FBGs as self-monitoring nondestructive testing devices.
Main Methods:
- Utilizing an intracore Bragg grating on a photosensitive fiber core for strain measurement.
- Correlating strain information with absolute changes in the Bragg-reflected wavelength.
- Discussing the application and temperature effects of FBG sensors in composite structures.
Main Results:
- Strain information is directly linked to the absolute shift in Bragg-reflected wavelength.
- FBG sensors are sensitive to both load-induced strain and temperature fluctuations.
- The potential for FBG sensors as self-monitoring nondestructive testing devices in composites is detailed.
Conclusions:
- FBG sensors are effective for monitoring strain in composite materials.
- Temperature compensation is crucial for accurate load-induced strain measurements.
- Embedded FBG sensors can serve as integral components for nondestructive testing and structural health monitoring.
Related Concept Videos
01:27Measurements of Strain
Strain quantifies the deformation of a material under force, typically measured as normal strain, which represents the change in length when compared with the original length. Electrical strain gauges are used for enhanced accuracy. These devices consist of a conductive wire mounted on a paper backing that adheres to the material's surface. These gauges operate on the piezoresistive effect, where the wire's electrical resistance changes in response to mechanical deformation. The strain gauge...
01:15Design Example: Strain Gauge Bridge or Wheatstone Bridge
The utilization of strain gauges as transducers for converting mechanical strain into electrical signals is a common practice in various engineering applications. These strain gauges are frequently integrated into Wheatstone bridge circuits to accurately measure parameters such as force or pressure. Within this context, each element within the circuit exhibits a resistance that undergoes subtle variations when subjected to mechanical strain. The primary objective is to convert minuscule...
01:15Strain and Elastic Modulus
The quantity that describes the deformation of a body under stress is known as strain. Strain is given as a fractional change in either length, volume, or geometry under tensile, volume (also known as bulk), or shear stress, respectively, and is a dimensionless quantity. The strain experienced by a body under tensile or compressive stress is called tensile or compressive strain, respectively. In contrast, the strain experienced under bulk stress and shear stress is known as volume and shear...
01:22Fiber Reinforced Concrete
Fiber-reinforced concrete significantly enhances the structural and nonstructural properties of traditional concrete by incorporating fibers like steel, glass, and polymers. These fibers, varying from natural ones such as sisal and cellulose to manufactured ones like polypropylene and Kevlar, are mixed into hydraulic cement with aggregates. Steel fibers, often preferred for their robustness, contribute to improved ductility, toughness, and post-cracking performance. The concrete is classified...
01:20Elastic Strain Energy for Shearing Stresses
As discussed in previous lessons, strain energy in a material is the energy stored when it is elastically deformed, a concept crucial in materials science and mechanical engineering. This energy results from the internal work done against the cohesive forces within the material. When a material undergoes shearing stress and corresponding shearing strain, the strain energy density, which is the energy stored per unit volume, is calculated. Within the elastic limit, where the stress is...
01:20Shearing Strain
The shearing strain represents a cubic element's angular change when subjected to shearing stress. This type of stress can transform a cube into an oblique parallelepiped without influencing normal strains. The cubic element experiences a significant transformation when exposed solely to shearing stress. Its shape alters from a perfect cube into a rhomboid, clearly demonstrating the effect of shearing strain. The degree of this strain is considered positive if it reduces the angle between the...