Purpose <p>The evolution mechanisms of multi-position rub-impact failure in aero-engines are not clear, which poses challenges for the early and timely elimination of risks. This study aims to investigate the multi-position rub-impact fault in a dual-rotor system and analyze its dynamic characteristics and energy transfer behavior.</p> Methods <p>A dynamic model of an aero-engine dual-rotor system is established to simulatemulti-position rub-impact fault. The concept of time-averaged rub-impact power flow is proposed, which not only reflects the severity of rub-impact faults, but also can be used to analyze the energy changes of the dual-rotor system. Then, the evolution mechanism and energy migration characteristics of a dual-rotor system from single-position rub-impact to multi-position rub-impact under different rubbing stiffness are revealed. Finally, a dual-rotor rub-impact test bench is built, high pressure (HP) and low pressure (LP) rub-impact experiments are carried out to verify the rich energy migration phenomenon.</p> Results <p>The results show that the rubbing stiffness is the primary parameter affecting the rub-impact behavior of the dual-rotor system and that local rub-impact is accompanied by a strong rebound collision effect when the value of rubbing stiffness is large. Complex energy migration occurs during the rubbing process, especially at the initial rubbing speed.</p> Conclusion <p>This study provides a new theoretical and experimental support for the energy domain diagnoses, early warnings and structural anti-rubbing optimization of the rub-impact fault of aero-engine dual-rotor systems. Its results are valuable for improving the operational reliability of aero-engines.</p>