Multiple reflections of Lamb waves at a delamination.

Area of Science:

• Solid Mechanics
• Materials Science
• Non-Destructive Testing

Background:

• Laminated plates are susceptible to internal defects like delaminations.
• Understanding wave propagation is crucial for structural health monitoring.
• Lamb waves are sensitive probes for detecting these defects.

Purpose of the Study:

• To investigate the behavior of fundamental Lamb modes interacting with delaminations in laminated plates.
• To analyze wave splitting, reflection, and transmission phenomena at delamination interfaces.
• To establish a relationship between wave reflections and delamination characteristics.

Main Methods:

• Utilized the semi-analytical finite element method for wave propagation analysis.
• Performed detailed numerical simulations to visualize wave interactions.
• Analyzed phase and arrival time differences of propagating waves.

Main Results:

• Lamb waves propagate towards delaminations and split into two independent waves at the entrance.
• Significant reflections are minimal at the delamination entrance.
• The two waves exit with different phases and arrival times, exciting reflected and transmitted waves.
• Multiple reflections occur at regular intervals, correlating with delamination size.

Conclusions:

• Delaminations cause unique wave splitting and multi-reflection patterns.
• These patterns provide a basis for quantifying delamination size through wave analysis.
• The semi-analytical finite element method is effective for studying such complex wave phenomena.