Inductive Frequency-Coded Sensor for Non-Destructive Structural Strain Monitoring of Composite Materials

Area of Science:

• Materials Science
• Electrical Engineering
• Mechanical Engineering

Background:

• Structural composite materials offer customizable mechanical properties for diverse applications like aerospace and wind energy.
• Effective non-invasive structural health monitoring (SHM) is crucial for ensuring the integrity of these advanced materials.
• Existing SHM methods often face limitations in sensitivity, cost, or integration complexity.

Purpose of the Study:

• To introduce a novel, frequency-coded sensor for non-destructive structural strain monitoring in composite materials.
• To develop an analytical and numerical model for the proposed sensor design.
• To validate the sensor's performance through electromagnetic simulations and experimental measurements.

Main Methods:

• A novel sensor design featuring three spiral resonators optimized for distinct frequencies, excited by a strip line.
• Analytical modeling using a circuital approach and numerical simulations within the 100-400 MHz frequency range.
• Experimental validation using printed circuit board (PCB) prototypes embedded in fiberglass composite samples.

Main Results:

• Electromagnetic full-wave simulations demonstrated promising results, which were subsequently confirmed by experimental measurements.
• The sensor exhibits exceptional sensitivity, cost-effectiveness, and ease of integration due to its minimal cabling and small profile.
• The frequency-coded configuration allows for accurate detection and differentiation of structural deformations based on severity and location.

Conclusions:

• The developed frequency-coded sensor is a highly effective and practical solution for non-destructive structural health monitoring of composite materials.
• The sensor's design offers a balance between penetration depth and system sensitivity, suitable for various composite applications.
• This technology holds significant potential for enhancing the safety and reliability of composite structures in critical industries.