Piezoelectric Transducers for Structural Health Monitoring of Joint Structures in Cylinders: A Wave-Based Design...

Area of Science:

• Mechanical Engineering
• Materials Science
• Acoustics

Background:

• Joints are critical in mechanical systems, but damage can cause complex wave scattering.
• Quantifying joint status relies on understanding wave mode conversion, posing a challenge for selective excitation and sensing.
• Existing methods struggle to isolate specific wave modes for accurate damage assessment.

Purpose of the Study:

• To investigate the relationship between local stiffness changes in flange joints and wave mode conversion.
• To design and validate wave-mode piezoelectric transducers for selective sensing of torsional, longitudinal, and flexural waves.
• To apply these transducers for monitoring the connection status of flange joints.

Main Methods:

• Wave Finite Element Method (WFEM) was used to calculate transmitted wave amplitudes and analyze stiffness change effects.
• Design of piezoelectric transducers utilizing material distribution to cancel non-target wave contributions.
• Numerical simulations to demonstrate selective coupling and voltage differences for target vs. non-target waves.
• Experimental validation of wave scattering simulations and WFEM results.

Main Results:

• A quantitative relationship between local stiffness changes and wave mode conversion was established.
• Designed piezoelectric transducers exhibited selective coupling, showing orders of magnitude voltage differences for target wave modes.
• Simulations and WFEM results for wave scattering were in good agreement.
• Four transducers were successfully applied to monitor flange connection status.

Conclusions:

• The study demonstrates a novel approach for selective wave mode sensing in mechanical joints.
• The developed piezoelectric transducers offer a promising tool for accurate structural health monitoring of flange connections.
• WFEM and numerical simulations are effective for analyzing wave propagation and scattering in jointed structures.