Abstract: Novel method of resonant fatigue testing achieved by two-dimension (abbr. 2D) high rotational valve controlled hydraulic cylinder is studied. Resonant fatigue testing scheme of 2D high rotational valve controlled asymmetrical hydraulic cylinder is proposed. Vibration frequency and amplitude of the fatigue test rig are controlled respectively by rotation and linear motion of the spool of 2D high rotational valve. The change of resonant frequency to the high frequency fatigue test rig is achieved by changing the initial position of the piston in the asymmetric cylinder. Mathematical models of 2D high rotational valve, asymmetrical hydraulic cylinder and the hydraulic system consisting of 2D high rotational valve controlled asymmetrical hydraulic cylinder are established. Nonlinear simulation model based on Simulink is used to study the impact of the damper on amplitude-frequency characteristics of the output load force, phase-frequency characteristics of the output load force and the flow rate, when the initial volume of the non-rod chamber of the asymmetric hydraulic cylinder is constant. And the waveform distortion of the output load force and the control method of the output load force amplitude are studied in the resonant working condition. Experimental results verify the feasibility of the novel method of electro-hydraulic resonant fatigue testing. The adoption of the scheme of 2D high rotational valve controlled asymmetric hydraulic cylinder can effectively increase the resonant frequency of electro-hydraulic fatigue testing and extend the application scope of resonant electro-hydraulic fatigue test rig.

Key words: electro-hydraulic, fatigue testing, resonance