Printed Crack Detection Sensors for SHM Based on Direct Ink Write Additive Manufacturing.

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Structural health monitoring (SHM) is crucial for assessing component integrity.
• Existing SHM technologies face limitations in sensitivity and precision for fatigue crack detection.
• Additive manufacturing offers potential for novel sensor fabrication.

Purpose of the Study:

• To present an innovative structural crack detection technique using printed adaptive sensors.
• To evaluate the fabrication repeatability, output stability, and crack detection capabilities of these sensors.
• To assess the suitability of the sensors as an alternative SHM technology.

Main Methods:

• Direct Ink Write (DIW) additive manufacturing was employed to fabricate sensors using conductive ink (silver microparticles) and polymer insulators.
• The sensors' output characteristics, fabrication tolerance, and stability were measured.
• A fatigue crack growth test was conducted to evaluate damage size estimation and sensor performance over 1.5 million cycles.

Main Results:

• Batch production of sensors demonstrated a tolerance within 5%.
• The crack gauge achieved high precision, estimating damage size with less than 1 mm error over 30 mm crack length.
• Sensors remained fully functional throughout 1.5 million cycles, showing no signal pattern changes related to failure.

Conclusions:

• The developed printed adaptive sensors exhibit high reliability for fatigue crack detection and propagation monitoring.
• The technique offers a promising and precise alternative to existing SHM technologies.
• Direct Ink Write manufacturing enables the creation of sensitive and stable crack detection sensors.