Preload Monitoring in Bolted Connection Using Piezoelectric-Based Smart Interface

Area of Science:

• Structural Engineering
• Materials Science
• Smart Structures

Background:

• Bolted connections are critical in girder structures, and monitoring their preload is essential for structural integrity.
• Existing methods for preload monitoring can be complex or invasive.
• Piezoelectric-based smart interfaces offer a promising non-destructive approach for structural health monitoring.

Purpose of the Study:

• To present a novel preload monitoring method for bolted girder connections.
• To investigate the relationship between bolt preload and electro-mechanical (EM) impedance signatures.
• To validate the proposed method through numerical modeling and experimental testing.

Main Methods:

• Formulation of a simplified electro-mechanical (EM) impedance model for a bolted connection with a piezoelectric smart interface.
• Finite element modeling (FEM) to simulate the bolted connection and identify sensitive frequency bands for impedance signatures.
• Experimental impedance measurements on a lab-scaled bolted girder connection to verify the method.

Main Results:

• The study successfully established a correlation between bolt preload and changes in EM impedance signatures.
• Finite element analysis identified a sensitive frequency band crucial for accurate preload monitoring.
• Experimental validation confirmed the method's ability to detect preload variations in bolted girder connections.

Conclusions:

• The presented piezoelectric-based smart interface method is effective for monitoring bolt preload in girder connections.
• The developed EM impedance model provides a mechanistic understanding of preload effects on signatures.
• This technique offers a viable non-destructive approach for assessing the health of bolted structures.