电液四轴高频疲劳强度试验系统研究

Electro-hydraulic High Frequency Fatigue Test System

传统的结构疲劳强度试验系统中,电液激振器受电液伺服阀频响特性的限制,激振频率在一定程度上难以提高,为此设计了一种新型的试验系统。采用2D阀控液压缸组成电液激振器的方案来提高激振频率,包括2D高频激振阀、液压缸和偏置控制伺服阀。在2D阀中,阀芯的旋转运动和轴向滑动对激振频率和幅值实现独立控制,激振频率主要由阀芯的转速决定,易于通过提高阀芯转速来实现高频激振,进而提高疲劳强度试验系统的激振频率。文章对上述方案进行了理论分析和实验验证。结果表明：仿真曲线与实验结果基本吻合,系统能在5~200 Hz范围内对试验对象进行同步加载试验,其频率、幅值连续可控。该系统已在实际中得到应用。

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 - 200 Hz, and the frequency and amplitude can be controlled continuously. The system has been applied in practice.