<p>Vibration characteristics are widely utilized as key indicators for assessing bearing condition. To analyze the complex vibration mechanisms resulting from single and compound defects in bearings, this paper introduces a five-degree-of-freedom dynamic model for deep groove rolling element bearings. The model, formulated based on Hertzian contact mechanics and validated through comprehensive experiments, incorporates key factors such as single and compound defects, dynamic coupling excitations among the rotating shaft, bearing housing, and bearing, as well as time-varying displacement excitations. Using the proposed model, we investigated the impact of defect locations and defect sizes on dynamic vibration responses of bearing system. Our findings reveal that for single defects, the amplitudes of characteristic frequencies are significantly larger than those of their harmonics. In the case of compound defects, the vibration response is not merely a linear superposition of individual defect responses, but rather involves complex interactions that amplify or modulate the resulting dynamics. Notably, as defect length increases, the vibration amplitude of the outer raceway characteristic frequency decreases, while the inner raceway and rolling elements exhibit increasing vibration amplitudes. These insights reveal the underlying dynamic mechanical properties of rolling bearings and contribute to the development of new diagnostic methods, potentially enhancing the accuracy of bearing defect diagnosis and predictive maintenance strategies.</p>