Influence of Uniaxial Loads on Local Resonances

Abstract

Accurate and reliable nondestructive evaluation (NDE) for stress measurement is essential for assessing structural performance and preventive maintenance. Local resonances offer an efficient NDE method due to their "amplified and localized" vibration amplitude. This allows for mounting or wiring near the structural edge without affecting the vibration modes. In this paper, we investigate the influence of stress level on the local resonances in a rectangular aluminum bar structure. In the first step, we utilize the electromechanical impedance method (EMI) to extract local resonances and verified them as Zero-Group-Velocity (ZGV) mode and cutoff frequency modes by performing two-dimensional fast Fourier transform (2D-FFT) on the wavefield. Furthermore, we investigate the influence of uniaxial tensile stress on the local resonance frequencies. It is observed that both the ZGV mode and cutoff frequency mode demonstrate a measurable sensitivity to the applied axial load.