Cross-axis Coupling and Phase Angle Effects due to Multiaxial Vibration

The response of structures under combined biaxial harmonic base excitation is investigated experimentally. The effect of cross-axis coupling, especially as a function of the relative phase angle between two vibration actuators is demonstrated. The experiments are performed using a unique multiaxial electrodynamic shaker with high degree of controllability. Increasing the phase angle between the rotational and translational excitation from 0o-135o increases the dynamic response of the structure and its nonlinear stiffness. The results are compared to both uniaxial rotational and translational vibration. The paper provides qualitative and quantitative differences between uniaxial and multiaxial nonlinear harmonic excitation with varying phase and fatigue build up.