Dr. Pavel I. Galich
18/12/2025
David Wang Auditorium, 3rd Floor, Dalia Maydan Bldg.
13:30
Magneto-active polymers (MAPs) enable remote, reversible tuning of mechanical properties through applied magnetic fields. In this seminar, I will start with recent theoretical and experimental advances on elastic wave propagation in isotropic MAPs. Using an enriched magnetoelastic framework that includes all relevant magneto-mechanical energy invariants, we derive explicit expressions for longitudinal (pressure) and transverse (shear) wave velocities as functions of magnetic field, deformation, and coupling parameters. The analysis predicts that, in undeformed isotropic MAPs, only the in-plane S-wave — polarized along the magnetic field — is magnetically tunable, while P-wave and out-of-plane S-wave (polarized perpendicular to the magnetic field) remain unaffected. Pulse-echo ultrasonic measurements on 3D-printed Iron-PLA composites confirm this selective tunability, revealing a measurable increase in in-plane S-wave speed with increasing magnetic field intensity.
Then, I will extend the discussion to soft magneto-active periodic bi-laminates composed of alternating incompressible hyperelastic magnetoelastic phases. For these bi-laminates, we obtain closed-form relations for field-induced deformation and the velocities of long S-waves, revealing their dependence on magnetic intensity, induced stretch, and propagation direction. From the long-wave analysis, we further derive explicit criteria for the critical magnetic field corresponding to the onset of macroscopic instability.
Together, these results provide a unified continuum framework linking magnetoelastic coupling, deformation, and elastic-wave propagation. They establish fundamental design principles for magnetically tunable metamaterials and smart structures enabling adaptive control of vibration.