Moein Abdi recently completed his Ph.D. in mechanical engineering at the University of Auckland, where his research focused on the free and forced vibration analysis of waveguides with nonlinear boundaries using a wave approach. He has worked on various topics in both linear and nonlinear vibration domains, encompassing the linear vibration of microcantilevers in Atomic Force Microscopy (AFM), nonlinear vibrations of continuous structures through wave propagation and reflection, and vibrations of metamaterial beams with grading piezoelectric elements. He is now working as a teaching technician at the University of Auckland and supporting multidisciplinary teaching spaces and overseeing laboratories for mechanical, civil, and structural engineering courses.
His PhD project concerned the free and forced vibrations of waveguides with nonlinear boundaries analytically, numerically and experimentally. The study investigates the reflection of time-harmonic waves in a waveguide featuring a nonlinear boundary stiffness, focusing on applications to rods and beams. Numerical examples illustrate energy leakage into higher harmonics, determining the minimum magnitudes of reflection coefficients for axial and flexural waves at the fundamental frequency. An experimental method for the measurement of reflection coefficients featuring a nonlinear boundary is studied and a nonlinear boundary configuration introduced characterized by cubic stiffness, representing essential nonlinearity. The results show that with multiple incident waves and for flexural vibration in the presence of nearfield waves the maximum energy that can leak into higher harmonics increases.
