Laser ultrasonics in a multilayer structure: Semi-analytic model and simulated examples.

Area of Science:

• Physics
• Materials Science
• Acoustics

Background:

• Laser-generated elastic waves involve complex electromagnetic, thermal, and elastic field couplings.
• Semi-analytic approaches offer fast and accurate solutions for multiphysical problems where analytical solutions exist.
• Nondestructive evaluation (NDE) of complex structures, like bonded assemblies, requires advanced simulation methods.

Purpose of the Study:

• To develop and present a semi-analytic multilayer model for simulating laser-generated ultrasound.
• To account for optical penetration, thermal conduction/convection, and coupled physical fields.
• To provide a computational tool for NDE applications in complex materials.

Main Methods:

• A multilayer model is proposed to solve electromagnetic, thermal, and elastodynamic problems sequentially.
• The model incorporates optical penetration from a laser line source.
• Thermal conduction and convection are included, along with optical, thermal, and mechanical coupling conditions between layers.

Main Results:

• The developed model successfully simulates laser-generated ultrasound in multilayer structures.
• The semi-analytic approach provides accurate and efficient results for opto-acoustic generation.
• The simulation is validated for its relevance in NDE of complex assemblies.

Conclusions:

• The proposed semi-analytic multilayer model is effective for simulating laser-generated ultrasound.
• This method is valuable for advancing NDE techniques for intricate structures.
• The study provides an open-source Python code for broader research accessibility.