Electro-hydraulic High Frequency Fatigue Test System

The working frequency of the electrohydraulic vibration exciters in conventional fatigue test system is limited to fairly narrow range by the frequency response capability of the servo valve.A novel system of electrohydraulic vibration exciter using a 2D valve(two-dimensional control valve) to control a hydraulic actuator is therefore proposed to enhance frequency response capability,including 2D valve,cylinder and bias control servo valve.In the 2D valve,the rotary and sliding motions are independently exploited to control the frequency and the magnitude of the vibration respectively.The frequency of the 2D valve controlled vibration exciter is determined by the rotary speed.By adjusting this factor in the 2D valve design,the proposed scheme of vibration exciter is apt to realize high-frequency vibration and to increase the working frequency of fatigue test system.The theoretical analysis and experimental verification are carried out in this paper.The results show that the simulation waveforms basically coincide with the experimental results,the tested object can be excited synchronously within the frequency 5~200Hz,and the frequency and amplitude can be controlled continuously.The system has been applied in practice.