Microstructured optical fiber sensors embedded in a laminate composite for smart material applications

Area of Science:

• Materials Science
• Optical Engineering
• Structural Health Monitoring

Background:

• Composite materials are increasingly used in demanding applications.
• Effective structural integrity monitoring is essential for safety and longevity.
• Existing monitoring techniques often lack the required sensitivity or robustness.

Purpose of the Study:

• To investigate the use of specialized Fiber Bragg gratings in microstructured optical fibers for strain sensing.
• To evaluate the performance of these sensors when embedded in composite materials.
• To demonstrate a significant improvement in transversal strain sensitivity for structural monitoring.

Main Methods:

• Fabrication of Fiber Bragg gratings in highly birefringent microstructured optical fibers.
• Embedding these gratings into a fiber-reinforced polymer composite.
• Controlled application of axial and transversal strain, and thermal cycling.
• Measurement of Bragg peak wavelength shifts to determine strain response.

Main Results:

• The embedded Fiber Bragg gratings effectively measured strain within the composite.
• A remarkable sensitivity to transversal strain was achieved, exceeding previous literature values by an order of magnitude.
• The sensors demonstrated reliable performance during thermal cycling.

Conclusions:

• Microstructured optical fibers offer a highly sensitive platform for strain sensing.
• The developed sensor system is well-suited for structural integrity monitoring of composite structures.
• This technology promises enhanced safety and performance monitoring for advanced materials.